From 8b10fe68985278de4926daa56ad6af701839e40a Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 10 Aug 2020 10:21:39 -0400 Subject: [PATCH 01/19] fscrypt: drop unused inode argument from fscrypt_fname_alloc_buffer Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/20200810142139.487631-1-jlayton@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fname.c | 5 +---- fs/crypto/hooks.c | 2 +- fs/ext4/dir.c | 2 +- fs/ext4/namei.c | 7 +++---- fs/f2fs/dir.c | 2 +- fs/ubifs/dir.c | 2 +- include/linux/fscrypt.h | 5 ++--- 7 files changed, 10 insertions(+), 15 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 011830f84d8d..47bcfddb278b 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -260,8 +260,6 @@ bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, /** * fscrypt_fname_alloc_buffer() - allocate a buffer for presented filenames - * @inode: inode of the parent directory (for regular filenames) - * or of the symlink (for symlink targets) * @max_encrypted_len: maximum length of encrypted filenames the buffer will be * used to present * @crypto_str: (output) buffer to allocate @@ -271,8 +269,7 @@ bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, * * Return: 0 on success, -errno on failure */ -int fscrypt_fname_alloc_buffer(const struct inode *inode, - u32 max_encrypted_len, +int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, struct fscrypt_str *crypto_str) { const u32 max_encoded_len = BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX); diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 09fb8aa0f2e9..491b252843eb 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -319,7 +319,7 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, if (cstr.len + sizeof(*sd) - 1 > max_size) return ERR_PTR(-EUCLEAN); - err = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr); + err = fscrypt_fname_alloc_buffer(cstr.len, &pstr); if (err) return ERR_PTR(err); diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index 1d82336b1cd4..efe77cffc322 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -148,7 +148,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx) } if (IS_ENCRYPTED(inode)) { - err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr); + err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, &fstr); if (err < 0) return err; } diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 153a9fbe1dd0..0d74615fcce3 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -663,8 +663,7 @@ static struct stats dx_show_leaf(struct inode *dir, /* Directory is encrypted */ res = fscrypt_fname_alloc_buffer( - dir, len, - &fname_crypto_str); + len, &fname_crypto_str); if (res) printk(KERN_WARNING "Error " "allocating crypto " @@ -1016,8 +1015,8 @@ static int htree_dirblock_to_tree(struct file *dir_file, brelse(bh); return err; } - err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN, - &fname_crypto_str); + err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, + &fname_crypto_str); if (err < 0) { brelse(bh); return err; diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 069f498af1e3..b2530b9507bd 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -1032,7 +1032,7 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx) if (err) goto out; - err = fscrypt_fname_alloc_buffer(inode, F2FS_NAME_LEN, &fstr); + err = fscrypt_fname_alloc_buffer(F2FS_NAME_LEN, &fstr); if (err < 0) goto out; } diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 9d042942d8b2..a9c1f5a9c9bd 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -515,7 +515,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx) if (err) return err; - err = fscrypt_fname_alloc_buffer(dir, UBIFS_MAX_NLEN, &fstr); + err = fscrypt_fname_alloc_buffer(UBIFS_MAX_NLEN, &fstr); if (err) return err; diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 991ff8575d0e..eaf16eb55788 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -197,7 +197,7 @@ static inline void fscrypt_free_filename(struct fscrypt_name *fname) kfree(fname->crypto_buf.name); } -int fscrypt_fname_alloc_buffer(const struct inode *inode, u32 max_encrypted_len, +int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, struct fscrypt_str *crypto_str); void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str); int fscrypt_fname_disk_to_usr(const struct inode *inode, @@ -428,8 +428,7 @@ static inline void fscrypt_free_filename(struct fscrypt_name *fname) return; } -static inline int fscrypt_fname_alloc_buffer(const struct inode *inode, - u32 max_encrypted_len, +static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, struct fscrypt_str *crypto_str) { return -EOPNOTSUPP; From 5e895bd4d5233cb054447d0491d4e63c8496d419 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 24 Aug 2020 13:38:41 -0700 Subject: [PATCH 02/19] fscrypt: restrict IV_INO_LBLK_32 to ino_bits <= 32 When an encryption policy has the IV_INO_LBLK_32 flag set, the IV generation method involves hashing the inode number. This is different from fscrypt's other IV generation methods, where the inode number is either not used at all or is included directly in the IVs. Therefore, in principle IV_INO_LBLK_32 can work with any length inode number. However, currently fscrypt gets the inode number from inode::i_ino, which is 'unsigned long'. So currently the implementation limit is actually 32 bits (like IV_INO_LBLK_64), since longer inode numbers will have been truncated by the VFS on 32-bit platforms. Fix fscrypt_supported_v2_policy() to enforce the correct limit. This doesn't actually matter currently, since only ext4 and f2fs support IV_INO_LBLK_32, and they both only support 32-bit inode numbers. But we might as well fix it in case it matters in the future. Ideally inode::i_ino would instead be made 64-bit, but for now it's not needed. (Note, this limit does *not* prevent filesystems with 64-bit inode numbers from adding fscrypt support, since IV_INO_LBLK_* support is optional and is useful only on certain hardware.) Fixes: e3b1078bedd3 ("fscrypt: add support for IV_INO_LBLK_32 policies") Reported-by: Jeff Layton Link: https://lore.kernel.org/r/20200824203841.1707847-1-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/policy.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 2d73fd39ad96..b92f34523178 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -192,10 +192,15 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, 32, 32)) return false; + /* + * IV_INO_LBLK_32 hashes the inode number, so in principle it can + * support any ino_bits. However, currently the inode number is gotten + * from inode::i_ino which is 'unsigned long'. So for now the + * implementation limit is 32 bits. + */ if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) && - /* This uses hashed inode numbers, so ino_bits doesn't matter. */ !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32", - INT_MAX, 32)) + 32, 32)) return false; if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) { From a992b20cd4ee360dbbe6f69339cb07146e4304d6 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:24 -0700 Subject: [PATCH 03/19] fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context() fscrypt_get_encryption_info() is intended to be GFP_NOFS-safe. But actually it isn't, since it uses functions like crypto_alloc_skcipher() which aren't GFP_NOFS-safe, even when called under memalloc_nofs_save(). Therefore it can deadlock when called from a context that needs GFP_NOFS, e.g. during an ext4 transaction or between f2fs_lock_op() and f2fs_unlock_op(). This happens when creating a new encrypted file. We can't fix this by just not setting up the key for new inodes right away, since new symlinks need their key to encrypt the symlink target. So we need to set up the new inode's key before starting the transaction. But just calling fscrypt_get_encryption_info() earlier doesn't work, since it assumes the encryption context is already set, and the encryption context can't be set until the transaction. The recently proposed fscrypt support for the ceph filesystem (https://lkml.kernel.org/linux-fscrypt/20200821182813.52570-1-jlayton@kernel.org/T/#u) will have this same ordering problem too, since ceph will need to encrypt new symlinks before setting their encryption context. Finally, f2fs can deadlock when the filesystem is mounted with '-o test_dummy_encryption' and a new file is created in an existing unencrypted directory. Similarly, this is caused by holding too many locks when calling fscrypt_get_encryption_info(). To solve all these problems, add new helper functions: - fscrypt_prepare_new_inode() sets up a new inode's encryption key (fscrypt_info), using the parent directory's encryption policy and a new random nonce. It neither reads nor writes the encryption context. - fscrypt_set_context() persists the encryption context of a new inode, using the information from the fscrypt_info already in memory. This replaces fscrypt_inherit_context(). Temporarily keep fscrypt_inherit_context() around until all filesystems have been converted to use fscrypt_set_context(). Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-2-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fscrypt_private.h | 3 + fs/crypto/keysetup.c | 197 +++++++++++++++++++++++++++--------- fs/crypto/policy.c | 62 ++++++++++-- include/linux/fscrypt.h | 17 ++++ 4 files changed, 224 insertions(+), 55 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 8117a61b6f55..355f6d937751 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -572,6 +572,9 @@ int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key); int fscrypt_derive_dirhash_key(struct fscrypt_info *ci, const struct fscrypt_master_key *mk); +void fscrypt_hash_inode_number(struct fscrypt_info *ci, + const struct fscrypt_master_key *mk); + /* keysetup_v1.c */ void fscrypt_put_direct_key(struct fscrypt_direct_key *dk); diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index fea6226afc2b..615916897214 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -10,6 +10,7 @@ #include #include +#include #include "fscrypt_private.h" @@ -222,6 +223,16 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci, return 0; } +void fscrypt_hash_inode_number(struct fscrypt_info *ci, + const struct fscrypt_master_key *mk) +{ + WARN_ON(ci->ci_inode->i_ino == 0); + WARN_ON(!mk->mk_ino_hash_key_initialized); + + ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino, + &mk->mk_ino_hash_key); +} + static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci, struct fscrypt_master_key *mk) { @@ -254,13 +265,20 @@ unlock: return err; } - ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino, - &mk->mk_ino_hash_key); + /* + * New inodes may not have an inode number assigned yet. + * Hashing their inode number is delayed until later. + */ + if (ci->ci_inode->i_ino == 0) + WARN_ON(!(ci->ci_inode->i_state & I_CREATING)); + else + fscrypt_hash_inode_number(ci, mk); return 0; } static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, - struct fscrypt_master_key *mk) + struct fscrypt_master_key *mk, + bool need_dirhash_key) { int err; @@ -306,7 +324,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, return err; /* Derive a secret dirhash key for directories that need it. */ - if (S_ISDIR(ci->ci_inode->i_mode) && IS_CASEFOLDED(ci->ci_inode)) { + if (need_dirhash_key) { err = fscrypt_derive_dirhash_key(ci, mk); if (err) return err; @@ -326,6 +344,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * key being removed with a new inode starting to use it. */ static int setup_file_encryption_key(struct fscrypt_info *ci, + bool need_dirhash_key, struct key **master_key_ret) { struct key *key; @@ -400,7 +419,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw); break; case FSCRYPT_POLICY_V2: - err = fscrypt_setup_v2_file_key(ci, mk); + err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key); break; default: WARN_ON(1); @@ -454,57 +473,28 @@ static void put_crypt_info(struct fscrypt_info *ci) kmem_cache_free(fscrypt_info_cachep, ci); } -int fscrypt_get_encryption_info(struct inode *inode) +static int +fscrypt_setup_encryption_info(struct inode *inode, + const union fscrypt_policy *policy, + const u8 nonce[FSCRYPT_FILE_NONCE_SIZE], + bool need_dirhash_key) { struct fscrypt_info *crypt_info; - union fscrypt_context ctx; struct fscrypt_mode *mode; struct key *master_key = NULL; int res; - if (fscrypt_has_encryption_key(inode)) - return 0; - res = fscrypt_initialize(inode->i_sb->s_cop->flags); if (res) return res; - res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); - if (res < 0) { - const union fscrypt_context *dummy_ctx = - fscrypt_get_dummy_context(inode->i_sb); - - if (IS_ENCRYPTED(inode) || !dummy_ctx) { - fscrypt_warn(inode, - "Error %d getting encryption context", - res); - return res; - } - /* Fake up a context for an unencrypted directory */ - res = fscrypt_context_size(dummy_ctx); - memcpy(&ctx, dummy_ctx, res); - } - crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS); if (!crypt_info) return -ENOMEM; crypt_info->ci_inode = inode; - - res = fscrypt_policy_from_context(&crypt_info->ci_policy, &ctx, res); - if (res) { - fscrypt_warn(inode, - "Unrecognized or corrupt encryption context"); - goto out; - } - - memcpy(crypt_info->ci_nonce, fscrypt_context_nonce(&ctx), - FSCRYPT_FILE_NONCE_SIZE); - - if (!fscrypt_supported_policy(&crypt_info->ci_policy, inode)) { - res = -EINVAL; - goto out; - } + crypt_info->ci_policy = *policy; + memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE); mode = select_encryption_mode(&crypt_info->ci_policy, inode); if (IS_ERR(mode)) { @@ -514,13 +504,14 @@ int fscrypt_get_encryption_info(struct inode *inode) WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE); crypt_info->ci_mode = mode; - res = setup_file_encryption_key(crypt_info, &master_key); + res = setup_file_encryption_key(crypt_info, need_dirhash_key, + &master_key); if (res) goto out; /* - * Multiple tasks may race to set ->i_crypt_info, so use - * cmpxchg_release(). This pairs with the smp_load_acquire() in + * For existing inodes, multiple tasks may race to set ->i_crypt_info. + * So use cmpxchg_release(). This pairs with the smp_load_acquire() in * fscrypt_get_info(). I.e., here we publish ->i_crypt_info with a * RELEASE barrier so that other tasks can ACQUIRE it. */ @@ -550,13 +541,127 @@ out: up_read(&mk->mk_secret_sem); key_put(master_key); } - if (res == -ENOKEY) - res = 0; put_crypt_info(crypt_info); return res; } + +/** + * fscrypt_get_encryption_info() - set up an inode's encryption key + * @inode: the inode to set up the key for + * + * Set up ->i_crypt_info, if it hasn't already been done. + * + * Note: unless ->i_crypt_info is already set, this isn't %GFP_NOFS-safe. So + * generally this shouldn't be called from within a filesystem transaction. + * + * Return: 0 if ->i_crypt_info was set or was already set, *or* if the + * encryption key is unavailable. (Use fscrypt_has_encryption_key() to + * distinguish these cases.) Also can return another -errno code. + */ +int fscrypt_get_encryption_info(struct inode *inode) +{ + int res; + union fscrypt_context ctx; + union fscrypt_policy policy; + + if (fscrypt_has_encryption_key(inode)) + return 0; + + res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); + if (res < 0) { + const union fscrypt_context *dummy_ctx = + fscrypt_get_dummy_context(inode->i_sb); + + if (IS_ENCRYPTED(inode) || !dummy_ctx) { + fscrypt_warn(inode, + "Error %d getting encryption context", + res); + return res; + } + /* Fake up a context for an unencrypted directory */ + res = fscrypt_context_size(dummy_ctx); + memcpy(&ctx, dummy_ctx, res); + } + + res = fscrypt_policy_from_context(&policy, &ctx, res); + if (res) { + fscrypt_warn(inode, + "Unrecognized or corrupt encryption context"); + return res; + } + + if (!fscrypt_supported_policy(&policy, inode)) + return -EINVAL; + + res = fscrypt_setup_encryption_info(inode, &policy, + fscrypt_context_nonce(&ctx), + IS_CASEFOLDED(inode) && + S_ISDIR(inode->i_mode)); + if (res == -ENOKEY) + res = 0; + return res; +} EXPORT_SYMBOL(fscrypt_get_encryption_info); +/** + * fscrypt_prepare_new_inode() - prepare to create a new inode in a directory + * @dir: a possibly-encrypted directory + * @inode: the new inode. ->i_mode must be set already. + * ->i_ino doesn't need to be set yet. + * @encrypt_ret: (output) set to %true if the new inode will be encrypted + * + * If the directory is encrypted, set up its ->i_crypt_info in preparation for + * encrypting the name of the new file. Also, if the new inode will be + * encrypted, set up its ->i_crypt_info and set *encrypt_ret=true. + * + * This isn't %GFP_NOFS-safe, and therefore it should be called before starting + * any filesystem transaction to create the inode. For this reason, ->i_ino + * isn't required to be set yet, as the filesystem may not have set it yet. + * + * This doesn't persist the new inode's encryption context. That still needs to + * be done later by calling fscrypt_set_context(). + * + * Return: 0 on success, -ENOKEY if the encryption key is missing, or another + * -errno code + */ +int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, + bool *encrypt_ret) +{ + int err; + u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; + + if (!IS_ENCRYPTED(dir) && fscrypt_get_dummy_context(dir->i_sb) == NULL) + return 0; + + err = fscrypt_get_encryption_info(dir); + if (err) + return err; + if (!fscrypt_has_encryption_key(dir)) + return -ENOKEY; + + if (WARN_ON_ONCE(inode->i_mode == 0)) + return -EINVAL; + + /* + * Only regular files, directories, and symlinks are encrypted. + * Special files like device nodes and named pipes aren't. + */ + if (!S_ISREG(inode->i_mode) && + !S_ISDIR(inode->i_mode) && + !S_ISLNK(inode->i_mode)) + return 0; + + *encrypt_ret = true; + + get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE); + return fscrypt_setup_encryption_info(inode, + &dir->i_crypt_info->ci_policy, + nonce, + IS_CASEFOLDED(dir) && + S_ISDIR(inode->i_mode)); +} +EXPORT_SYMBOL_GPL(fscrypt_prepare_new_inode); + /** * fscrypt_put_encryption_info() - free most of an inode's fscrypt data * @inode: an inode being evicted diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index b92f34523178..7e96953d385e 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -236,18 +236,19 @@ bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, } /** - * fscrypt_new_context_from_policy() - create a new fscrypt_context from - * an fscrypt_policy + * fscrypt_new_context() - create a new fscrypt_context * @ctx_u: output context * @policy_u: input policy + * @nonce: nonce to use * * Create an fscrypt_context for an inode that is being assigned the given - * encryption policy. A new nonce is randomly generated. + * encryption policy. @nonce must be a new random nonce. * * Return: the size of the new context in bytes. */ -static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u, - const union fscrypt_policy *policy_u) +static int fscrypt_new_context(union fscrypt_context *ctx_u, + const union fscrypt_policy *policy_u, + const u8 nonce[FSCRYPT_FILE_NONCE_SIZE]) { memset(ctx_u, 0, sizeof(*ctx_u)); @@ -265,7 +266,7 @@ static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u, memcpy(ctx->master_key_descriptor, policy->master_key_descriptor, sizeof(ctx->master_key_descriptor)); - get_random_bytes(ctx->nonce, sizeof(ctx->nonce)); + memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE); return sizeof(*ctx); } case FSCRYPT_POLICY_V2: { @@ -281,7 +282,7 @@ static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u, memcpy(ctx->master_key_identifier, policy->master_key_identifier, sizeof(ctx->master_key_identifier)); - get_random_bytes(ctx->nonce, sizeof(ctx->nonce)); + memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE); return sizeof(*ctx); } } @@ -377,6 +378,7 @@ static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy) static int set_encryption_policy(struct inode *inode, const union fscrypt_policy *policy) { + u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; union fscrypt_context ctx; int ctxsize; int err; @@ -414,7 +416,8 @@ static int set_encryption_policy(struct inode *inode, return -EINVAL; } - ctxsize = fscrypt_new_context_from_policy(&ctx, policy); + get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE); + ctxsize = fscrypt_new_context(&ctx, policy, nonce); return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, NULL); } @@ -637,6 +640,7 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context); int fscrypt_inherit_context(struct inode *parent, struct inode *child, void *fs_data, bool preload) { + u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; union fscrypt_context ctx; int ctxsize; struct fscrypt_info *ci; @@ -650,7 +654,8 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child, if (ci == NULL) return -ENOKEY; - ctxsize = fscrypt_new_context_from_policy(&ctx, &ci->ci_policy); + get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE); + ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, nonce); BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE); res = parent->i_sb->s_cop->set_context(child, &ctx, ctxsize, fs_data); @@ -660,6 +665,45 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child, } EXPORT_SYMBOL(fscrypt_inherit_context); +/** + * fscrypt_set_context() - Set the fscrypt context of a new inode + * @inode: a new inode + * @fs_data: private data given by FS and passed to ->set_context() + * + * This should be called after fscrypt_prepare_new_inode(), generally during a + * filesystem transaction. Everything here must be %GFP_NOFS-safe. + * + * Return: 0 on success, -errno on failure + */ +int fscrypt_set_context(struct inode *inode, void *fs_data) +{ + struct fscrypt_info *ci = inode->i_crypt_info; + union fscrypt_context ctx; + int ctxsize; + + /* fscrypt_prepare_new_inode() should have set up the key already. */ + if (WARN_ON_ONCE(!ci)) + return -ENOKEY; + + BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE); + ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, ci->ci_nonce); + + /* + * This may be the first time the inode number is available, so do any + * delayed key setup that requires the inode number. + */ + if (ci->ci_policy.version == FSCRYPT_POLICY_V2 && + (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) { + const struct fscrypt_master_key *mk = + ci->ci_master_key->payload.data[0]; + + fscrypt_hash_inode_number(ci, mk); + } + + return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data); +} +EXPORT_SYMBOL_GPL(fscrypt_set_context); + /** * fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption' * @sb: the filesystem on which test_dummy_encryption is being specified diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index eaf16eb55788..9cf7ca90f3ab 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -158,6 +158,7 @@ int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg); int fscrypt_has_permitted_context(struct inode *parent, struct inode *child); int fscrypt_inherit_context(struct inode *parent, struct inode *child, void *fs_data, bool preload); +int fscrypt_set_context(struct inode *inode, void *fs_data); struct fscrypt_dummy_context { const union fscrypt_context *ctx; @@ -184,6 +185,8 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg); /* keysetup.c */ int fscrypt_get_encryption_info(struct inode *inode); +int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, + bool *encrypt_ret); void fscrypt_put_encryption_info(struct inode *inode); void fscrypt_free_inode(struct inode *inode); int fscrypt_drop_inode(struct inode *inode); @@ -347,6 +350,11 @@ static inline int fscrypt_inherit_context(struct inode *parent, return -EOPNOTSUPP; } +static inline int fscrypt_set_context(struct inode *inode, void *fs_data) +{ + return -EOPNOTSUPP; +} + struct fscrypt_dummy_context { }; @@ -394,6 +402,15 @@ static inline int fscrypt_get_encryption_info(struct inode *inode) return -EOPNOTSUPP; } +static inline int fscrypt_prepare_new_inode(struct inode *dir, + struct inode *inode, + bool *encrypt_ret) +{ + if (IS_ENCRYPTED(dir)) + return -EOPNOTSUPP; + return 0; +} + static inline void fscrypt_put_encryption_info(struct inode *inode) { return; From 177cc0e71008b7a0737bf55c88538d0b9e6e9191 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:25 -0700 Subject: [PATCH 04/19] ext4: factor out ext4_xattr_credits_for_new_inode() To compute a new inode's xattr credits, we need to know whether the inode will be encrypted or not. When we switch to use the new helper function fscrypt_prepare_new_inode(), we won't find out whether the inode will be encrypted until slightly later than is currently the case. That will require moving the code block that computes the xattr credits. To make this easier and reduce the length of __ext4_new_inode(), move this code block into a new function ext4_xattr_credits_for_new_inode(). Link: https://lore.kernel.org/r/20200917041136.178600-3-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/ext4/ialloc.c | 90 +++++++++++++++++++++++++++--------------------- 1 file changed, 51 insertions(+), 39 deletions(-) diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index df25d38d6539..0cc576005a92 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -742,6 +742,53 @@ not_found: return 1; } +static int ext4_xattr_credits_for_new_inode(struct inode *dir, mode_t mode, + bool encrypt) +{ + struct super_block *sb = dir->i_sb; + int nblocks = 0; +#ifdef CONFIG_EXT4_FS_POSIX_ACL + struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT); + + if (IS_ERR(p)) + return PTR_ERR(p); + if (p) { + int acl_size = p->a_count * sizeof(ext4_acl_entry); + + nblocks += (S_ISDIR(mode) ? 2 : 1) * + __ext4_xattr_set_credits(sb, NULL /* inode */, + NULL /* block_bh */, acl_size, + true /* is_create */); + posix_acl_release(p); + } +#endif + +#ifdef CONFIG_SECURITY + { + int num_security_xattrs = 1; + +#ifdef CONFIG_INTEGRITY + num_security_xattrs++; +#endif + /* + * We assume that security xattrs are never more than 1k. + * In practice they are under 128 bytes. + */ + nblocks += num_security_xattrs * + __ext4_xattr_set_credits(sb, NULL /* inode */, + NULL /* block_bh */, 1024, + true /* is_create */); + } +#endif + if (encrypt) + nblocks += __ext4_xattr_set_credits(sb, + NULL /* inode */, + NULL /* block_bh */, + FSCRYPT_SET_CONTEXT_MAX_SIZE, + true /* is_create */); + return nblocks; +} + /* * There are two policies for allocating an inode. If the new inode is * a directory, then a forward search is made for a block group with both @@ -796,45 +843,10 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir, } if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) { -#ifdef CONFIG_EXT4_FS_POSIX_ACL - struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT); - - if (IS_ERR(p)) - return ERR_CAST(p); - if (p) { - int acl_size = p->a_count * sizeof(ext4_acl_entry); - - nblocks += (S_ISDIR(mode) ? 2 : 1) * - __ext4_xattr_set_credits(sb, NULL /* inode */, - NULL /* block_bh */, acl_size, - true /* is_create */); - posix_acl_release(p); - } -#endif - -#ifdef CONFIG_SECURITY - { - int num_security_xattrs = 1; - -#ifdef CONFIG_INTEGRITY - num_security_xattrs++; -#endif - /* - * We assume that security xattrs are never - * more than 1k. In practice they are under - * 128 bytes. - */ - nblocks += num_security_xattrs * - __ext4_xattr_set_credits(sb, NULL /* inode */, - NULL /* block_bh */, 1024, - true /* is_create */); - } -#endif - if (encrypt) - nblocks += __ext4_xattr_set_credits(sb, - NULL /* inode */, NULL /* block_bh */, - FSCRYPT_SET_CONTEXT_MAX_SIZE, - true /* is_create */); + ret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt); + if (ret2 < 0) + return ERR_PTR(ret2); + nblocks += ret2; } ngroups = ext4_get_groups_count(sb); From 02ce5316afc86274c55c7b07a81ad6411d28f077 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:26 -0700 Subject: [PATCH 05/19] ext4: use fscrypt_prepare_new_inode() and fscrypt_set_context() Convert ext4 to use the new functions fscrypt_prepare_new_inode() and fscrypt_set_context(). This avoids calling fscrypt_get_encryption_info() from within a transaction, which can deadlock because fscrypt_get_encryption_info() isn't GFP_NOFS-safe. For more details about this problem, see the earlier patch "fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()". Link: https://lore.kernel.org/r/20200917041136.178600-4-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/ext4/ialloc.c | 37 +++++++++++++++++-------------------- 1 file changed, 17 insertions(+), 20 deletions(-) diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 0cc576005a92..698ca4a4db5f 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -819,7 +819,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir, ext4_group_t i; ext4_group_t flex_group; struct ext4_group_info *grp; - int encrypt = 0; + bool encrypt = false; /* Cannot create files in a deleted directory */ if (!dir || !dir->i_nlink) @@ -831,24 +831,6 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir, if (unlikely(ext4_forced_shutdown(sbi))) return ERR_PTR(-EIO); - if ((IS_ENCRYPTED(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) && - (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) && - !(i_flags & EXT4_EA_INODE_FL)) { - err = fscrypt_get_encryption_info(dir); - if (err) - return ERR_PTR(err); - if (!fscrypt_has_encryption_key(dir)) - return ERR_PTR(-ENOKEY); - encrypt = 1; - } - - if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) { - ret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt); - if (ret2 < 0) - return ERR_PTR(ret2); - nblocks += ret2; - } - ngroups = ext4_get_groups_count(sb); trace_ext4_request_inode(dir, mode); inode = new_inode(sb); @@ -878,10 +860,25 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir, else ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID); + if (!(i_flags & EXT4_EA_INODE_FL)) { + err = fscrypt_prepare_new_inode(dir, inode, &encrypt); + if (err) + goto out; + } + err = dquot_initialize(inode); if (err) goto out; + if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) { + ret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt); + if (ret2 < 0) { + err = ret2; + goto out; + } + nblocks += ret2; + } + if (!goal) goal = sbi->s_inode_goal; @@ -1174,7 +1171,7 @@ got: * prevent its deduplication. */ if (encrypt) { - err = fscrypt_inherit_context(dir, inode, handle, true); + err = fscrypt_set_context(inode, handle); if (err) goto fail_free_drop; } From e075b6901047cd4c70b93cfcbe5f67dbc5741fb6 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:27 -0700 Subject: [PATCH 06/19] f2fs: use fscrypt_prepare_new_inode() and fscrypt_set_context() Convert f2fs to use the new functions fscrypt_prepare_new_inode() and fscrypt_set_context(). This avoids calling fscrypt_get_encryption_info() from under f2fs_lock_op(), which can deadlock because fscrypt_get_encryption_info() isn't GFP_NOFS-safe. For more details about this problem, see the earlier patch "fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()". This also fixes a f2fs-specific deadlock when the filesystem is mounted with '-o test_dummy_encryption' and a file is created in an unencrypted directory other than the root directory: INFO: task touch:207 blocked for more than 30 seconds. Not tainted 5.9.0-rc4-00099-g729e3d0919844 #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:touch state:D stack: 0 pid: 207 ppid: 167 flags:0x00000000 Call Trace: [...] lock_page include/linux/pagemap.h:548 [inline] pagecache_get_page+0x25e/0x310 mm/filemap.c:1682 find_or_create_page include/linux/pagemap.h:348 [inline] grab_cache_page include/linux/pagemap.h:424 [inline] f2fs_grab_cache_page fs/f2fs/f2fs.h:2395 [inline] f2fs_grab_cache_page fs/f2fs/f2fs.h:2373 [inline] __get_node_page.part.0+0x39/0x2d0 fs/f2fs/node.c:1350 __get_node_page fs/f2fs/node.c:35 [inline] f2fs_get_node_page+0x2e/0x60 fs/f2fs/node.c:1399 read_inline_xattr+0x88/0x140 fs/f2fs/xattr.c:288 lookup_all_xattrs+0x1f9/0x2c0 fs/f2fs/xattr.c:344 f2fs_getxattr+0x9b/0x160 fs/f2fs/xattr.c:532 f2fs_get_context+0x1e/0x20 fs/f2fs/super.c:2460 fscrypt_get_encryption_info+0x9b/0x450 fs/crypto/keysetup.c:472 fscrypt_inherit_context+0x2f/0xb0 fs/crypto/policy.c:640 f2fs_init_inode_metadata+0xab/0x340 fs/f2fs/dir.c:540 f2fs_add_inline_entry+0x145/0x390 fs/f2fs/inline.c:621 f2fs_add_dentry+0x31/0x80 fs/f2fs/dir.c:757 f2fs_do_add_link+0xcd/0x130 fs/f2fs/dir.c:798 f2fs_add_link fs/f2fs/f2fs.h:3234 [inline] f2fs_create+0x104/0x290 fs/f2fs/namei.c:344 lookup_open.isra.0+0x2de/0x500 fs/namei.c:3103 open_last_lookups+0xa9/0x340 fs/namei.c:3177 path_openat+0x8f/0x1b0 fs/namei.c:3365 do_filp_open+0x87/0x130 fs/namei.c:3395 do_sys_openat2+0x96/0x150 fs/open.c:1168 [...] That happened because f2fs_add_inline_entry() locks the directory inode's page in order to add the dentry, then f2fs_get_context() tries to lock it recursively in order to read the encryption xattr. This problem is specific to "test_dummy_encryption" because normally the directory's fscrypt_info would be set up prior to f2fs_add_inline_entry() in order to encrypt the new filename. Regardless, the new design fixes this test_dummy_encryption deadlock as well as potential deadlocks with fs reclaim, by setting up any needed fscrypt_info structs prior to taking so many locks. The test_dummy_encryption deadlock was reported by Daniel Rosenberg. Reported-by: Daniel Rosenberg Acked-by: Jaegeuk Kim Link: https://lore.kernel.org/r/20200917041136.178600-5-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/f2fs/dir.c | 2 +- fs/f2fs/f2fs.h | 23 ----------------------- fs/f2fs/namei.c | 7 ++++++- 3 files changed, 7 insertions(+), 25 deletions(-) diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index b2530b9507bd..414bc94fbd54 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -537,7 +537,7 @@ struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir, goto put_error; if (IS_ENCRYPTED(inode)) { - err = fscrypt_inherit_context(dir, inode, page, false); + err = fscrypt_set_context(inode, page); if (err) goto put_error; } diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index d9e52a7f3702..0503371f88ed 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1315,13 +1315,6 @@ enum fsync_mode { #define IS_IO_TRACED_PAGE(page) (0) #endif -#ifdef CONFIG_FS_ENCRYPTION -#define DUMMY_ENCRYPTION_ENABLED(sbi) \ - (unlikely(F2FS_OPTION(sbi).dummy_enc_ctx.ctx != NULL)) -#else -#define DUMMY_ENCRYPTION_ENABLED(sbi) (0) -#endif - /* For compression */ enum compress_algorithm_type { COMPRESS_LZO, @@ -4022,22 +4015,6 @@ static inline bool f2fs_lfs_mode(struct f2fs_sb_info *sbi) return F2FS_OPTION(sbi).fs_mode == FS_MODE_LFS; } -static inline bool f2fs_may_encrypt(struct inode *dir, struct inode *inode) -{ -#ifdef CONFIG_FS_ENCRYPTION - struct f2fs_sb_info *sbi = F2FS_I_SB(dir); - umode_t mode = inode->i_mode; - - /* - * If the directory encrypted or dummy encryption enabled, - * then we should encrypt the inode. - */ - if (IS_ENCRYPTED(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) - return (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)); -#endif - return false; -} - static inline bool f2fs_may_compress(struct inode *inode) { if (IS_SWAPFILE(inode) || f2fs_is_pinned_file(inode) || diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c index 84e4bbc1a64d..45f324511a19 100644 --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -28,6 +28,7 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode) nid_t ino; struct inode *inode; bool nid_free = false; + bool encrypt = false; int xattr_size = 0; int err; @@ -69,13 +70,17 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode) F2FS_I(inode)->i_projid = make_kprojid(&init_user_ns, F2FS_DEF_PROJID); + err = fscrypt_prepare_new_inode(dir, inode, &encrypt); + if (err) + goto fail_drop; + err = dquot_initialize(inode); if (err) goto fail_drop; set_inode_flag(inode, FI_NEW_INODE); - if (f2fs_may_encrypt(dir, inode)) + if (encrypt) f2fs_set_encrypted_inode(inode); if (f2fs_sb_has_extra_attr(sbi)) { From 4c030fa8870e9f0c53bcb91c607476ce7a4d6f2a Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:28 -0700 Subject: [PATCH 07/19] ubifs: use fscrypt_prepare_new_inode() and fscrypt_set_context() Convert ubifs to use the new functions fscrypt_prepare_new_inode() and fscrypt_set_context(). Unlike ext4 and f2fs, this doesn't appear to fix any deadlock bug. But it does shorten the code slightly and get all filesystems using the same helper functions, so that fscrypt_inherit_context() can be removed. It also fixes an incorrect error code where ubifs returned EPERM instead of the expected ENOKEY. Link: https://lore.kernel.org/r/20200917041136.178600-6-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/ubifs/dir.c | 38 ++++++++++++++++---------------------- 1 file changed, 16 insertions(+), 22 deletions(-) diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index a9c1f5a9c9bd..155521e51ac5 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -81,19 +81,6 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir, struct ubifs_inode *ui; bool encrypted = false; - if (IS_ENCRYPTED(dir)) { - err = fscrypt_get_encryption_info(dir); - if (err) { - ubifs_err(c, "fscrypt_get_encryption_info failed: %i", err); - return ERR_PTR(err); - } - - if (!fscrypt_has_encryption_key(dir)) - return ERR_PTR(-EPERM); - - encrypted = true; - } - inode = new_inode(c->vfs_sb); ui = ubifs_inode(inode); if (!inode) @@ -112,6 +99,12 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir, current_time(inode); inode->i_mapping->nrpages = 0; + err = fscrypt_prepare_new_inode(dir, inode, &encrypted); + if (err) { + ubifs_err(c, "fscrypt_prepare_new_inode failed: %i", err); + goto out_iput; + } + switch (mode & S_IFMT) { case S_IFREG: inode->i_mapping->a_ops = &ubifs_file_address_operations; @@ -131,7 +124,6 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir, case S_IFBLK: case S_IFCHR: inode->i_op = &ubifs_file_inode_operations; - encrypted = false; break; default: BUG(); @@ -151,9 +143,8 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir, if (c->highest_inum >= INUM_WATERMARK) { spin_unlock(&c->cnt_lock); ubifs_err(c, "out of inode numbers"); - make_bad_inode(inode); - iput(inode); - return ERR_PTR(-EINVAL); + err = -EINVAL; + goto out_iput; } ubifs_warn(c, "running out of inode numbers (current %lu, max %u)", (unsigned long)c->highest_inum, INUM_WATERMARK); @@ -171,16 +162,19 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir, spin_unlock(&c->cnt_lock); if (encrypted) { - err = fscrypt_inherit_context(dir, inode, &encrypted, true); + err = fscrypt_set_context(inode, NULL); if (err) { - ubifs_err(c, "fscrypt_inherit_context failed: %i", err); - make_bad_inode(inode); - iput(inode); - return ERR_PTR(err); + ubifs_err(c, "fscrypt_set_context failed: %i", err); + goto out_iput; } } return inode; + +out_iput: + make_bad_inode(inode); + iput(inode); + return ERR_PTR(err); } static int dbg_check_name(const struct ubifs_info *c, From ae9ff8ad81b13f2acb27c52f1d402f4d0d10d7d1 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:29 -0700 Subject: [PATCH 08/19] fscrypt: adjust logging for in-creation inodes Now that a fscrypt_info may be set up for inodes that are currently being created and haven't yet had an inode number assigned, avoid logging confusing messages about "inode 0". Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-7-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/crypto.c | 4 +++- fs/crypto/keyring.c | 9 +++++++-- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 9212325763b0..4ef3f714046a 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -343,9 +343,11 @@ void fscrypt_msg(const struct inode *inode, const char *level, va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; - if (inode) + if (inode && inode->i_ino) printk("%sfscrypt (%s, inode %lu): %pV\n", level, inode->i_sb->s_id, inode->i_ino, &vaf); + else if (inode) + printk("%sfscrypt (%s): %pV\n", level, inode->i_sb->s_id, &vaf); else printk("%sfscrypt: %pV\n", level, &vaf); va_end(args); diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index e74f239c4428..53cc552a7b8f 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -817,6 +817,7 @@ static int check_for_busy_inodes(struct super_block *sb, struct list_head *pos; size_t busy_count = 0; unsigned long ino; + char ino_str[50] = ""; spin_lock(&mk->mk_decrypted_inodes_lock); @@ -838,11 +839,15 @@ static int check_for_busy_inodes(struct super_block *sb, } spin_unlock(&mk->mk_decrypted_inodes_lock); + /* If the inode is currently being created, ino may still be 0. */ + if (ino) + snprintf(ino_str, sizeof(ino_str), ", including ino %lu", ino); + fscrypt_warn(NULL, - "%s: %zu inode(s) still busy after removing key with %s %*phN, including ino %lu", + "%s: %zu inode(s) still busy after removing key with %s %*phN%s", sb->s_id, busy_count, master_key_spec_type(&mk->mk_spec), master_key_spec_len(&mk->mk_spec), (u8 *)&mk->mk_spec.u, - ino); + ino_str); return -EBUSY; } From e9d5e31d2fe39825b0fc276b14f2a322faf3c77b Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:30 -0700 Subject: [PATCH 09/19] fscrypt: remove fscrypt_inherit_context() Now that all filesystems have been converted to use fscrypt_prepare_new_inode() and fscrypt_set_context(), fscrypt_inherit_context() is no longer used. Remove it. Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-8-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/policy.c | 37 ------------------------------------- include/linux/fscrypt.h | 9 --------- 2 files changed, 46 deletions(-) diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 7e96953d385e..4ff893f7b030 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -628,43 +628,6 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) } EXPORT_SYMBOL(fscrypt_has_permitted_context); -/** - * fscrypt_inherit_context() - Sets a child context from its parent - * @parent: Parent inode from which the context is inherited. - * @child: Child inode that inherits the context from @parent. - * @fs_data: private data given by FS. - * @preload: preload child i_crypt_info if true - * - * Return: 0 on success, -errno on failure - */ -int fscrypt_inherit_context(struct inode *parent, struct inode *child, - void *fs_data, bool preload) -{ - u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; - union fscrypt_context ctx; - int ctxsize; - struct fscrypt_info *ci; - int res; - - res = fscrypt_get_encryption_info(parent); - if (res < 0) - return res; - - ci = fscrypt_get_info(parent); - if (ci == NULL) - return -ENOKEY; - - get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE); - ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, nonce); - - BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE); - res = parent->i_sb->s_cop->set_context(child, &ctx, ctxsize, fs_data); - if (res) - return res; - return preload ? fscrypt_get_encryption_info(child): 0; -} -EXPORT_SYMBOL(fscrypt_inherit_context); - /** * fscrypt_set_context() - Set the fscrypt context of a new inode * @inode: a new inode diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 9cf7ca90f3ab..81d6ded24328 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -156,8 +156,6 @@ int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg); int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg); int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg); int fscrypt_has_permitted_context(struct inode *parent, struct inode *child); -int fscrypt_inherit_context(struct inode *parent, struct inode *child, - void *fs_data, bool preload); int fscrypt_set_context(struct inode *inode, void *fs_data); struct fscrypt_dummy_context { @@ -343,13 +341,6 @@ static inline int fscrypt_has_permitted_context(struct inode *parent, return 0; } -static inline int fscrypt_inherit_context(struct inode *parent, - struct inode *child, - void *fs_data, bool preload) -{ - return -EOPNOTSUPP; -} - static inline int fscrypt_set_context(struct inode *inode, void *fs_data) { return -EOPNOTSUPP; From 4cc1a3e7e8520226c62019553b18f1c12388a99d Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:31 -0700 Subject: [PATCH 10/19] fscrypt: require that fscrypt_encrypt_symlink() already has key Now that all filesystems have been converted to use fscrypt_prepare_new_inode(), the encryption key for new symlink inodes is now already set up whenever we try to encrypt the symlink target. Enforce this rather than try to set up the key again when it may be too late to do so safely. Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-9-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/hooks.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 491b252843eb..7748db509240 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -217,9 +217,13 @@ int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, struct fscrypt_symlink_data *sd; unsigned int ciphertext_len; - err = fscrypt_require_key(inode); - if (err) - return err; + /* + * fscrypt_prepare_new_inode() should have already set up the new + * symlink inode's encryption key. We don't wait until now to do it, + * since we may be in a filesystem transaction now. + */ + if (WARN_ON_ONCE(!fscrypt_has_encryption_key(inode))) + return -ENOKEY; if (disk_link->name) { /* filesystem-provided buffer */ From 9dad5feb49a5c3b99838b102555cdbedf244320a Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:32 -0700 Subject: [PATCH 11/19] fscrypt: stop pretending that key setup is nofs-safe fscrypt_get_encryption_info() has never actually been safe to call in a context that needs GFP_NOFS, since it calls crypto_alloc_skcipher(). crypto_alloc_skcipher() isn't GFP_NOFS-safe, even if called under memalloc_nofs_save(). This is because it may load kernel modules, and also because it internally takes crypto_alg_sem. Other tasks can do GFP_KERNEL allocations while holding crypto_alg_sem for write. The use of fscrypt_init_mutex isn't GFP_NOFS-safe either. So, stop pretending that fscrypt_get_encryption_info() is nofs-safe. I.e., when it allocates memory, just use GFP_KERNEL instead of GFP_NOFS. Note, another reason to do this is that GFP_NOFS is deprecated in favor of using memalloc_nofs_save() in the proper places. Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-10-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/inline_crypt.c | 7 ++----- fs/crypto/keysetup.c | 2 +- fs/crypto/keysetup_v1.c | 8 ++++---- 3 files changed, 7 insertions(+), 10 deletions(-) diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index faa25541ccb6..89bffa82ed74 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -106,7 +106,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_info *ci) crypto_cfg.data_unit_size = sb->s_blocksize; crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci); num_devs = fscrypt_get_num_devices(sb); - devs = kmalloc_array(num_devs, sizeof(*devs), GFP_NOFS); + devs = kmalloc_array(num_devs, sizeof(*devs), GFP_KERNEL); if (!devs) return -ENOMEM; fscrypt_get_devices(sb, num_devs, devs); @@ -135,9 +135,8 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, struct fscrypt_blk_crypto_key *blk_key; int err; int i; - unsigned int flags; - blk_key = kzalloc(struct_size(blk_key, devs, num_devs), GFP_NOFS); + blk_key = kzalloc(struct_size(blk_key, devs, num_devs), GFP_KERNEL); if (!blk_key) return -ENOMEM; @@ -166,10 +165,8 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, } queue_refs++; - flags = memalloc_nofs_save(); err = blk_crypto_start_using_key(&blk_key->base, blk_key->devs[i]); - memalloc_nofs_restore(flags); if (err) { fscrypt_err(inode, "error %d starting to use blk-crypto", err); diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 615916897214..47f19061ba10 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -488,7 +488,7 @@ fscrypt_setup_encryption_info(struct inode *inode, if (res) return res; - crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS); + crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_KERNEL); if (!crypt_info) return -ENOMEM; diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index a3cb52572b05..2762c5350432 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -60,7 +60,7 @@ static int derive_key_aes(const u8 *master_key, goto out; } crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); - req = skcipher_request_alloc(tfm, GFP_NOFS); + req = skcipher_request_alloc(tfm, GFP_KERNEL); if (!req) { res = -ENOMEM; goto out; @@ -99,7 +99,7 @@ find_and_lock_process_key(const char *prefix, const struct user_key_payload *ukp; const struct fscrypt_key *payload; - description = kasprintf(GFP_NOFS, "%s%*phN", prefix, + description = kasprintf(GFP_KERNEL, "%s%*phN", prefix, FSCRYPT_KEY_DESCRIPTOR_SIZE, descriptor); if (!description) return ERR_PTR(-ENOMEM); @@ -228,7 +228,7 @@ fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key) return dk; /* Nope, allocate one. */ - dk = kzalloc(sizeof(*dk), GFP_NOFS); + dk = kzalloc(sizeof(*dk), GFP_KERNEL); if (!dk) return ERR_PTR(-ENOMEM); refcount_set(&dk->dk_refcount, 1); @@ -272,7 +272,7 @@ static int setup_v1_file_key_derived(struct fscrypt_info *ci, * This cannot be a stack buffer because it will be passed to the * scatterlist crypto API during derive_key_aes(). */ - derived_key = kmalloc(ci->ci_mode->keysize, GFP_NOFS); + derived_key = kmalloc(ci->ci_mode->keysize, GFP_KERNEL); if (!derived_key) return -ENOMEM; From c7f0207b613033c56b1217032d2f6326d0c69217 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:33 -0700 Subject: [PATCH 12/19] fscrypt: make "#define fscrypt_policy" user-only The fscrypt UAPI header defines fscrypt_policy to fscrypt_policy_v1, for source compatibility with old userspace programs. Internally, the kernel doesn't want that compatibility definition. Instead, fscrypt_private.h #undefs it and re-defines it to a union. That works for now. However, in order to add fscrypt_operations::get_dummy_policy(), we'll need to forward declare 'union fscrypt_policy' in include/linux/fscrypt.h. That would cause build errors because "fscrypt_policy" is used in ioctl numbers. To avoid this, modify the UAPI header to make the fscrypt_policy compatibility definition conditional on !__KERNEL__, and make the ioctls use fscrypt_policy_v1 instead of fscrypt_policy. Note that this doesn't change the actual ioctl numbers. Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-11-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fscrypt_private.h | 1 - include/uapi/linux/fscrypt.h | 6 +++--- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 355f6d937751..ac3352086ee4 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -97,7 +97,6 @@ static inline const u8 *fscrypt_context_nonce(const union fscrypt_context *ctx) return NULL; } -#undef fscrypt_policy union fscrypt_policy { u8 version; struct fscrypt_policy_v1 v1; diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index 7875709ccfeb..e5de60336938 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -45,7 +45,6 @@ struct fscrypt_policy_v1 { __u8 flags; __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; }; -#define fscrypt_policy fscrypt_policy_v1 /* * Process-subscribed "logon" key description prefix and payload format. @@ -156,9 +155,9 @@ struct fscrypt_get_key_status_arg { __u32 __out_reserved[13]; }; -#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy) +#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy_v1) #define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16]) -#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy) +#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy_v1) #define FS_IOC_GET_ENCRYPTION_POLICY_EX _IOWR('f', 22, __u8[9]) /* size + version */ #define FS_IOC_ADD_ENCRYPTION_KEY _IOWR('f', 23, struct fscrypt_add_key_arg) #define FS_IOC_REMOVE_ENCRYPTION_KEY _IOWR('f', 24, struct fscrypt_remove_key_arg) @@ -170,6 +169,7 @@ struct fscrypt_get_key_status_arg { /* old names; don't add anything new here! */ #ifndef __KERNEL__ +#define fscrypt_policy fscrypt_policy_v1 #define FS_KEY_DESCRIPTOR_SIZE FSCRYPT_KEY_DESCRIPTOR_SIZE #define FS_POLICY_FLAGS_PAD_4 FSCRYPT_POLICY_FLAGS_PAD_4 #define FS_POLICY_FLAGS_PAD_8 FSCRYPT_POLICY_FLAGS_PAD_8 From 31114726b69364f3bf8dd945c600ceed4c430f4f Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:34 -0700 Subject: [PATCH 13/19] fscrypt: move fscrypt_prepare_symlink() out-of-line In preparation for moving the logic for "get the encryption policy inherited by new files in this directory" to a single place, make fscrypt_prepare_symlink() a regular function rather than an inline function that wraps __fscrypt_prepare_symlink(). This way, the new function fscrypt_policy_to_inherit() won't need to be exported to filesystems. Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-12-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/hooks.c | 39 ++++++++++++++++++++++--- include/linux/fscrypt.h | 63 ++++++++++------------------------------- 2 files changed, 50 insertions(+), 52 deletions(-) diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 7748db509240..a399c54947f2 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -166,12 +166,43 @@ int fscrypt_prepare_setflags(struct inode *inode, return 0; } -int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len, - unsigned int max_len, - struct fscrypt_str *disk_link) +/** + * fscrypt_prepare_symlink() - prepare to create a possibly-encrypted symlink + * @dir: directory in which the symlink is being created + * @target: plaintext symlink target + * @len: length of @target excluding null terminator + * @max_len: space the filesystem has available to store the symlink target + * @disk_link: (out) the on-disk symlink target being prepared + * + * This function computes the size the symlink target will require on-disk, + * stores it in @disk_link->len, and validates it against @max_len. An + * encrypted symlink may be longer than the original. + * + * Additionally, @disk_link->name is set to @target if the symlink will be + * unencrypted, but left NULL if the symlink will be encrypted. For encrypted + * symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the + * on-disk target later. (The reason for the two-step process is that some + * filesystems need to know the size of the symlink target before creating the + * inode, e.g. to determine whether it will be a "fast" or "slow" symlink.) + * + * Return: 0 on success, -ENAMETOOLONG if the symlink target is too long, + * -ENOKEY if the encryption key is missing, or another -errno code if a problem + * occurred while setting up the encryption key. + */ +int fscrypt_prepare_symlink(struct inode *dir, const char *target, + unsigned int len, unsigned int max_len, + struct fscrypt_str *disk_link) { int err; + if (!IS_ENCRYPTED(dir) && !fscrypt_get_dummy_context(dir->i_sb)) { + disk_link->name = (unsigned char *)target; + disk_link->len = len + 1; + if (disk_link->len > max_len) + return -ENAMETOOLONG; + return 0; + } + /* * To calculate the size of the encrypted symlink target we need to know * the amount of NUL padding, which is determined by the flags set in @@ -207,7 +238,7 @@ int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len, disk_link->name = NULL; return 0; } -EXPORT_SYMBOL_GPL(__fscrypt_prepare_symlink); +EXPORT_SYMBOL_GPL(fscrypt_prepare_symlink); int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, unsigned int len, struct fscrypt_str *disk_link) diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 81d6ded24328..39e7397a3f10 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -225,9 +225,9 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, struct fscrypt_name *fname); int fscrypt_prepare_setflags(struct inode *inode, unsigned int oldflags, unsigned int flags); -int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len, - unsigned int max_len, - struct fscrypt_str *disk_link); +int fscrypt_prepare_symlink(struct inode *dir, const char *target, + unsigned int len, unsigned int max_len, + struct fscrypt_str *disk_link); int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, unsigned int len, struct fscrypt_str *disk_link); const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, @@ -520,15 +520,21 @@ static inline int fscrypt_prepare_setflags(struct inode *inode, return 0; } -static inline int __fscrypt_prepare_symlink(struct inode *dir, - unsigned int len, - unsigned int max_len, - struct fscrypt_str *disk_link) +static inline int fscrypt_prepare_symlink(struct inode *dir, + const char *target, + unsigned int len, + unsigned int max_len, + struct fscrypt_str *disk_link) { - return -EOPNOTSUPP; + if (IS_ENCRYPTED(dir)) + return -EOPNOTSUPP; + disk_link->name = (unsigned char *)target; + disk_link->len = len + 1; + if (disk_link->len > max_len) + return -ENAMETOOLONG; + return 0; } - static inline int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, unsigned int len, @@ -793,45 +799,6 @@ static inline int fscrypt_prepare_setattr(struct dentry *dentry, return 0; } -/** - * fscrypt_prepare_symlink() - prepare to create a possibly-encrypted symlink - * @dir: directory in which the symlink is being created - * @target: plaintext symlink target - * @len: length of @target excluding null terminator - * @max_len: space the filesystem has available to store the symlink target - * @disk_link: (out) the on-disk symlink target being prepared - * - * This function computes the size the symlink target will require on-disk, - * stores it in @disk_link->len, and validates it against @max_len. An - * encrypted symlink may be longer than the original. - * - * Additionally, @disk_link->name is set to @target if the symlink will be - * unencrypted, but left NULL if the symlink will be encrypted. For encrypted - * symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the - * on-disk target later. (The reason for the two-step process is that some - * filesystems need to know the size of the symlink target before creating the - * inode, e.g. to determine whether it will be a "fast" or "slow" symlink.) - * - * Return: 0 on success, -ENAMETOOLONG if the symlink target is too long, - * -ENOKEY if the encryption key is missing, or another -errno code if a problem - * occurred while setting up the encryption key. - */ -static inline int fscrypt_prepare_symlink(struct inode *dir, - const char *target, - unsigned int len, - unsigned int max_len, - struct fscrypt_str *disk_link) -{ - if (IS_ENCRYPTED(dir) || fscrypt_get_dummy_context(dir->i_sb) != NULL) - return __fscrypt_prepare_symlink(dir, len, max_len, disk_link); - - disk_link->name = (unsigned char *)target; - disk_link->len = len + 1; - if (disk_link->len > max_len) - return -ENAMETOOLONG; - return 0; -} - /** * fscrypt_encrypt_symlink() - encrypt the symlink target if needed * @inode: symlink inode From ac4acb1f4b2b6b7e8d913537cccec8789903e164 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:35 -0700 Subject: [PATCH 14/19] fscrypt: handle test_dummy_encryption in more logical way The behavior of the test_dummy_encryption mount option is that when a new file (or directory or symlink) is created in an unencrypted directory, it's automatically encrypted using a dummy encryption policy. That's it; in particular, the encryption (or lack thereof) of existing files (or directories or symlinks) doesn't change. Unfortunately the implementation of test_dummy_encryption is a bit weird and confusing. When test_dummy_encryption is enabled and a file is being created in an unencrypted directory, we set up an encryption key (->i_crypt_info) for the directory. This isn't actually used to do any encryption, however, since the directory is still unencrypted! Instead, ->i_crypt_info is only used for inheriting the encryption policy. One consequence of this is that the filesystem ends up providing a "dummy context" (policy + nonce) instead of a "dummy policy". In commit ed318a6cc0b6 ("fscrypt: support test_dummy_encryption=v2"), I mistakenly thought this was required. However, actually the nonce only ends up being used to derive a key that is never used. Another consequence of this implementation is that it allows for 'inode->i_crypt_info != NULL && !IS_ENCRYPTED(inode)', which is an edge case that can be forgotten about. For example, currently FS_IOC_GET_ENCRYPTION_POLICY on an unencrypted directory may return the dummy encryption policy when the filesystem is mounted with test_dummy_encryption. That seems like the wrong thing to do, since again, the directory itself is not actually encrypted. Therefore, switch to a more logical and maintainable implementation where the dummy encryption policy inheritance is done without setting up keys for unencrypted directories. This involves: - Adding a function fscrypt_policy_to_inherit() which returns the encryption policy to inherit from a directory. This can be a real policy, a dummy policy, or no policy. - Replacing struct fscrypt_dummy_context, ->get_dummy_context(), etc. with struct fscrypt_dummy_policy, ->get_dummy_policy(), etc. - Making fscrypt_fname_encrypted_size() take an fscrypt_policy instead of an inode. Acked-by: Jaegeuk Kim Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-13-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fname.c | 11 ++-- fs/crypto/fscrypt_private.h | 6 +- fs/crypto/hooks.c | 30 ++++------ fs/crypto/keysetup.c | 33 +++-------- fs/crypto/policy.c | 113 ++++++++++++++++++++++-------------- fs/ext4/ext4.h | 6 +- fs/ext4/super.c | 16 ++--- fs/f2fs/f2fs.h | 2 +- fs/f2fs/super.c | 15 +++-- include/linux/fscrypt.h | 40 +++++-------- 10 files changed, 132 insertions(+), 140 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 47bcfddb278b..eb13408b50a7 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -242,11 +242,11 @@ static int base64_decode(const char *src, int len, u8 *dst) return cp - dst; } -bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, - u32 max_len, u32 *encrypted_len_ret) +bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, + u32 orig_len, u32 max_len, + u32 *encrypted_len_ret) { - const struct fscrypt_info *ci = inode->i_crypt_info; - int padding = 4 << (fscrypt_policy_flags(&ci->ci_policy) & + int padding = 4 << (fscrypt_policy_flags(policy) & FSCRYPT_POLICY_FLAGS_PAD_MASK); u32 encrypted_len; @@ -418,7 +418,8 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, return ret; if (fscrypt_has_encryption_key(dir)) { - if (!fscrypt_fname_encrypted_size(dir, iname->len, + if (!fscrypt_fname_encrypted_size(&dir->i_crypt_info->ci_policy, + iname->len, dir->i_sb->s_cop->max_namelen, &fname->crypto_buf.len)) return -ENAMETOOLONG; diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index ac3352086ee4..4f5806a3b73d 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -291,8 +291,9 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, /* fname.c */ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, u8 *out, unsigned int olen); -bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, - u32 max_len, u32 *encrypted_len_ret); +bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, + u32 orig_len, u32 max_len, + u32 *encrypted_len_ret); extern const struct dentry_operations fscrypt_d_ops; /* hkdf.c */ @@ -592,5 +593,6 @@ bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, int fscrypt_policy_from_context(union fscrypt_policy *policy_u, const union fscrypt_context *ctx_u, int ctx_size); +const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir); #endif /* _FSCRYPT_PRIVATE_H */ diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index a399c54947f2..42f5ee9f592d 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -193,30 +193,24 @@ int fscrypt_prepare_symlink(struct inode *dir, const char *target, unsigned int len, unsigned int max_len, struct fscrypt_str *disk_link) { - int err; + const union fscrypt_policy *policy; - if (!IS_ENCRYPTED(dir) && !fscrypt_get_dummy_context(dir->i_sb)) { + /* + * To calculate the size of the encrypted symlink target we need to know + * the amount of NUL padding, which is determined by the flags set in + * the encryption policy which will be inherited from the directory. + */ + policy = fscrypt_policy_to_inherit(dir); + if (policy == NULL) { + /* Not encrypted */ disk_link->name = (unsigned char *)target; disk_link->len = len + 1; if (disk_link->len > max_len) return -ENAMETOOLONG; return 0; } - - /* - * To calculate the size of the encrypted symlink target we need to know - * the amount of NUL padding, which is determined by the flags set in - * the encryption policy which will be inherited from the directory. - * The easiest way to get access to this is to just load the directory's - * fscrypt_info, since we'll need it to create the dir_entry anyway. - * - * Note: in test_dummy_encryption mode, @dir may be unencrypted. - */ - err = fscrypt_get_encryption_info(dir); - if (err) - return err; - if (!fscrypt_has_encryption_key(dir)) - return -ENOKEY; + if (IS_ERR(policy)) + return PTR_ERR(policy); /* * Calculate the size of the encrypted symlink and verify it won't @@ -229,7 +223,7 @@ int fscrypt_prepare_symlink(struct inode *dir, const char *target, * counting it (even though it is meaningless for ciphertext) is simpler * for now since filesystems will assume it is there and subtract it. */ - if (!fscrypt_fname_encrypted_size(dir, len, + if (!fscrypt_fname_encrypted_size(policy, len, max_len - sizeof(struct fscrypt_symlink_data), &disk_link->len)) return -ENAMETOOLONG; diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 47f19061ba10..d3c3e5d9b41f 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -547,7 +547,7 @@ out: /** * fscrypt_get_encryption_info() - set up an inode's encryption key - * @inode: the inode to set up the key for + * @inode: the inode to set up the key for. Must be encrypted. * * Set up ->i_crypt_info, if it hasn't already been done. * @@ -569,18 +569,8 @@ int fscrypt_get_encryption_info(struct inode *inode) res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); if (res < 0) { - const union fscrypt_context *dummy_ctx = - fscrypt_get_dummy_context(inode->i_sb); - - if (IS_ENCRYPTED(inode) || !dummy_ctx) { - fscrypt_warn(inode, - "Error %d getting encryption context", - res); - return res; - } - /* Fake up a context for an unencrypted directory */ - res = fscrypt_context_size(dummy_ctx); - memcpy(&ctx, dummy_ctx, res); + fscrypt_warn(inode, "Error %d getting encryption context", res); + return res; } res = fscrypt_policy_from_context(&policy, &ctx, res); @@ -627,17 +617,14 @@ EXPORT_SYMBOL(fscrypt_get_encryption_info); int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, bool *encrypt_ret) { - int err; + const union fscrypt_policy *policy; u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; - if (!IS_ENCRYPTED(dir) && fscrypt_get_dummy_context(dir->i_sb) == NULL) + policy = fscrypt_policy_to_inherit(dir); + if (policy == NULL) return 0; - - err = fscrypt_get_encryption_info(dir); - if (err) - return err; - if (!fscrypt_has_encryption_key(dir)) - return -ENOKEY; + if (IS_ERR(policy)) + return PTR_ERR(policy); if (WARN_ON_ONCE(inode->i_mode == 0)) return -EINVAL; @@ -654,9 +641,7 @@ int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, *encrypt_ret = true; get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE); - return fscrypt_setup_encryption_info(inode, - &dir->i_crypt_info->ci_policy, - nonce, + return fscrypt_setup_encryption_info(inode, policy, nonce, IS_CASEFOLDED(dir) && S_ISDIR(inode->i_mode)); } diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 4ff893f7b030..97cf07543651 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -32,6 +32,14 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1, return !memcmp(policy1, policy2, fscrypt_policy_size(policy1)); } +static const union fscrypt_policy * +fscrypt_get_dummy_policy(struct super_block *sb) +{ + if (!sb->s_cop->get_dummy_policy) + return NULL; + return sb->s_cop->get_dummy_policy(sb); +} + static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode) { if (contents_mode == FSCRYPT_MODE_AES_256_XTS && @@ -628,6 +636,25 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) } EXPORT_SYMBOL(fscrypt_has_permitted_context); +/* + * Return the encryption policy that new files in the directory will inherit, or + * NULL if none, or an ERR_PTR() on error. If the directory is encrypted, also + * ensure that its key is set up, so that the new filename can be encrypted. + */ +const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir) +{ + int err; + + if (IS_ENCRYPTED(dir)) { + err = fscrypt_require_key(dir); + if (err) + return ERR_PTR(err); + return &dir->i_crypt_info->ci_policy; + } + + return fscrypt_get_dummy_policy(dir->i_sb); +} + /** * fscrypt_set_context() - Set the fscrypt context of a new inode * @inode: a new inode @@ -672,31 +699,28 @@ EXPORT_SYMBOL_GPL(fscrypt_set_context); * @sb: the filesystem on which test_dummy_encryption is being specified * @arg: the argument to the test_dummy_encryption option. * If no argument was specified, then @arg->from == NULL. - * @dummy_ctx: the filesystem's current dummy context (input/output, see below) + * @dummy_policy: the filesystem's current dummy policy (input/output, see + * below) * * Handle the test_dummy_encryption mount option by creating a dummy encryption - * context, saving it in @dummy_ctx, and adding the corresponding dummy - * encryption key to the filesystem. If the @dummy_ctx is already set, then + * policy, saving it in @dummy_policy, and adding the corresponding dummy + * encryption key to the filesystem. If the @dummy_policy is already set, then * instead validate that it matches @arg. Don't support changing it via * remount, as that is difficult to do safely. * - * The reason we use an fscrypt_context rather than an fscrypt_policy is because - * we mustn't generate a new nonce each time we access a dummy-encrypted - * directory, as that would change the way filenames are encrypted. - * - * Return: 0 on success (dummy context set, or the same context is already set); - * -EEXIST if a different dummy context is already set; + * Return: 0 on success (dummy policy set, or the same policy is already set); + * -EEXIST if a different dummy policy is already set; * or another -errno value. */ int fscrypt_set_test_dummy_encryption(struct super_block *sb, const substring_t *arg, - struct fscrypt_dummy_context *dummy_ctx) + struct fscrypt_dummy_policy *dummy_policy) { const char *argstr = "v2"; const char *argstr_to_free = NULL; struct fscrypt_key_specifier key_spec = { 0 }; int version; - union fscrypt_context *ctx = NULL; + union fscrypt_policy *policy = NULL; int err; if (arg->from) { @@ -706,12 +730,12 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb, } if (!strcmp(argstr, "v1")) { - version = FSCRYPT_CONTEXT_V1; + version = FSCRYPT_POLICY_V1; key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR; memset(key_spec.u.descriptor, 0x42, FSCRYPT_KEY_DESCRIPTOR_SIZE); } else if (!strcmp(argstr, "v2")) { - version = FSCRYPT_CONTEXT_V2; + version = FSCRYPT_POLICY_V2; key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER; /* key_spec.u.identifier gets filled in when adding the key */ } else { @@ -719,21 +743,8 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb, goto out; } - if (dummy_ctx->ctx) { - /* - * Note: if we ever make test_dummy_encryption support - * specifying other encryption settings, such as the encryption - * modes, we'll need to compare those settings here. - */ - if (dummy_ctx->ctx->version == version) - err = 0; - else - err = -EEXIST; - goto out; - } - - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); - if (!ctx) { + policy = kzalloc(sizeof(*policy), GFP_KERNEL); + if (!policy) { err = -ENOMEM; goto out; } @@ -742,18 +753,18 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb, if (err) goto out; - ctx->version = version; - switch (ctx->version) { - case FSCRYPT_CONTEXT_V1: - ctx->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS; - ctx->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS; - memcpy(ctx->v1.master_key_descriptor, key_spec.u.descriptor, + policy->version = version; + switch (policy->version) { + case FSCRYPT_POLICY_V1: + policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS; + policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS; + memcpy(policy->v1.master_key_descriptor, key_spec.u.descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE); break; - case FSCRYPT_CONTEXT_V2: - ctx->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS; - ctx->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS; - memcpy(ctx->v2.master_key_identifier, key_spec.u.identifier, + case FSCRYPT_POLICY_V2: + policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS; + policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS; + memcpy(policy->v2.master_key_identifier, key_spec.u.identifier, FSCRYPT_KEY_IDENTIFIER_SIZE); break; default: @@ -761,11 +772,19 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb, err = -EINVAL; goto out; } - dummy_ctx->ctx = ctx; - ctx = NULL; + + if (dummy_policy->policy) { + if (fscrypt_policies_equal(policy, dummy_policy->policy)) + err = 0; + else + err = -EEXIST; + goto out; + } + dummy_policy->policy = policy; + policy = NULL; err = 0; out: - kfree(ctx); + kfree(policy); kfree(argstr_to_free); return err; } @@ -783,10 +802,16 @@ EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption); void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, struct super_block *sb) { - const union fscrypt_context *ctx = fscrypt_get_dummy_context(sb); + const union fscrypt_policy *policy = fscrypt_get_dummy_policy(sb); + int vers; - if (!ctx) + if (!policy) return; - seq_printf(seq, "%ctest_dummy_encryption=v%d", sep, ctx->version); + + vers = policy->version; + if (vers == FSCRYPT_POLICY_V1) /* Handle numbering quirk */ + vers = 1; + + seq_printf(seq, "%ctest_dummy_encryption=v%d", sep, vers); } EXPORT_SYMBOL_GPL(fscrypt_show_test_dummy_encryption); diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 523e00d7b392..f9a692c0a66c 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1401,7 +1401,7 @@ struct ext4_super_block { #define EXT4_MF_FS_ABORTED 0x0002 /* Fatal error detected */ #ifdef CONFIG_FS_ENCRYPTION -#define DUMMY_ENCRYPTION_ENABLED(sbi) ((sbi)->s_dummy_enc_ctx.ctx != NULL) +#define DUMMY_ENCRYPTION_ENABLED(sbi) ((sbi)->s_dummy_enc_policy.policy != NULL) #else #define DUMMY_ENCRYPTION_ENABLED(sbi) (0) #endif @@ -1596,8 +1596,8 @@ struct ext4_sb_info { atomic_t s_warning_count; atomic_t s_msg_count; - /* Encryption context for '-o test_dummy_encryption' */ - struct fscrypt_dummy_context s_dummy_enc_ctx; + /* Encryption policy for '-o test_dummy_encryption' */ + struct fscrypt_dummy_policy s_dummy_enc_policy; /* * Barrier between writepages ops and changing any inode's JOURNAL_DATA diff --git a/fs/ext4/super.c b/fs/ext4/super.c index ea425b49b345..aa6f64badf58 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1104,7 +1104,7 @@ static void ext4_put_super(struct super_block *sb) crypto_free_shash(sbi->s_chksum_driver); kfree(sbi->s_blockgroup_lock); fs_put_dax(sbi->s_daxdev); - fscrypt_free_dummy_context(&sbi->s_dummy_enc_ctx); + fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy); #ifdef CONFIG_UNICODE utf8_unload(sbi->s_encoding); #endif @@ -1392,10 +1392,9 @@ retry: return res; } -static const union fscrypt_context * -ext4_get_dummy_context(struct super_block *sb) +static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb) { - return EXT4_SB(sb)->s_dummy_enc_ctx.ctx; + return EXT4_SB(sb)->s_dummy_enc_policy.policy; } static bool ext4_has_stable_inodes(struct super_block *sb) @@ -1414,7 +1413,7 @@ static const struct fscrypt_operations ext4_cryptops = { .key_prefix = "ext4:", .get_context = ext4_get_context, .set_context = ext4_set_context, - .get_dummy_context = ext4_get_dummy_context, + .get_dummy_policy = ext4_get_dummy_policy, .empty_dir = ext4_empty_dir, .max_namelen = EXT4_NAME_LEN, .has_stable_inodes = ext4_has_stable_inodes, @@ -1888,12 +1887,13 @@ static int ext4_set_test_dummy_encryption(struct super_block *sb, * needed to allow it to be set or changed during remount. We do allow * it to be specified during remount, but only if there is no change. */ - if (is_remount && !sbi->s_dummy_enc_ctx.ctx) { + if (is_remount && !sbi->s_dummy_enc_policy.policy) { ext4_msg(sb, KERN_WARNING, "Can't set test_dummy_encryption on remount"); return -1; } - err = fscrypt_set_test_dummy_encryption(sb, arg, &sbi->s_dummy_enc_ctx); + err = fscrypt_set_test_dummy_encryption(sb, arg, + &sbi->s_dummy_enc_policy); if (err) { if (err == -EEXIST) ext4_msg(sb, KERN_WARNING, @@ -4935,7 +4935,7 @@ failed_mount: for (i = 0; i < EXT4_MAXQUOTAS; i++) kfree(get_qf_name(sb, sbi, i)); #endif - fscrypt_free_dummy_context(&sbi->s_dummy_enc_ctx); + fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy); ext4_blkdev_remove(sbi); brelse(bh); out_fail: diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 0503371f88ed..7c089ff7ff94 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -138,7 +138,7 @@ struct f2fs_mount_info { int fsync_mode; /* fsync policy */ int fs_mode; /* fs mode: LFS or ADAPTIVE */ int bggc_mode; /* bggc mode: off, on or sync */ - struct fscrypt_dummy_context dummy_enc_ctx; /* test dummy encryption */ + struct fscrypt_dummy_policy dummy_enc_policy; /* test dummy encryption */ block_t unusable_cap_perc; /* percentage for cap */ block_t unusable_cap; /* Amount of space allowed to be * unusable when disabling checkpoint diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index dfa072fa8081..f05ee33f5f26 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -433,12 +433,12 @@ static int f2fs_set_test_dummy_encryption(struct super_block *sb, * needed to allow it to be set or changed during remount. We do allow * it to be specified during remount, but only if there is no change. */ - if (is_remount && !F2FS_OPTION(sbi).dummy_enc_ctx.ctx) { + if (is_remount && !F2FS_OPTION(sbi).dummy_enc_policy.policy) { f2fs_warn(sbi, "Can't set test_dummy_encryption on remount"); return -EINVAL; } err = fscrypt_set_test_dummy_encryption( - sb, arg, &F2FS_OPTION(sbi).dummy_enc_ctx); + sb, arg, &F2FS_OPTION(sbi).dummy_enc_policy); if (err) { if (err == -EEXIST) f2fs_warn(sbi, @@ -1275,7 +1275,7 @@ static void f2fs_put_super(struct super_block *sb) for (i = 0; i < MAXQUOTAS; i++) kfree(F2FS_OPTION(sbi).s_qf_names[i]); #endif - fscrypt_free_dummy_context(&F2FS_OPTION(sbi).dummy_enc_ctx); + fscrypt_free_dummy_policy(&F2FS_OPTION(sbi).dummy_enc_policy); destroy_percpu_info(sbi); for (i = 0; i < NR_PAGE_TYPE; i++) kvfree(sbi->write_io[i]); @@ -2482,10 +2482,9 @@ static int f2fs_set_context(struct inode *inode, const void *ctx, size_t len, ctx, len, fs_data, XATTR_CREATE); } -static const union fscrypt_context * -f2fs_get_dummy_context(struct super_block *sb) +static const union fscrypt_policy *f2fs_get_dummy_policy(struct super_block *sb) { - return F2FS_OPTION(F2FS_SB(sb)).dummy_enc_ctx.ctx; + return F2FS_OPTION(F2FS_SB(sb)).dummy_enc_policy.policy; } static bool f2fs_has_stable_inodes(struct super_block *sb) @@ -2523,7 +2522,7 @@ static const struct fscrypt_operations f2fs_cryptops = { .key_prefix = "f2fs:", .get_context = f2fs_get_context, .set_context = f2fs_set_context, - .get_dummy_context = f2fs_get_dummy_context, + .get_dummy_policy = f2fs_get_dummy_policy, .empty_dir = f2fs_empty_dir, .max_namelen = F2FS_NAME_LEN, .has_stable_inodes = f2fs_has_stable_inodes, @@ -3864,7 +3863,7 @@ free_options: for (i = 0; i < MAXQUOTAS; i++) kfree(F2FS_OPTION(sbi).s_qf_names[i]); #endif - fscrypt_free_dummy_context(&F2FS_OPTION(sbi).dummy_enc_ctx); + fscrypt_free_dummy_policy(&F2FS_OPTION(sbi).dummy_enc_policy); kvfree(options); free_sb_buf: kfree(raw_super); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 39e7397a3f10..b3b0c5675c6b 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -21,7 +21,7 @@ #define FS_CRYPTO_BLOCK_SIZE 16 -union fscrypt_context; +union fscrypt_policy; struct fscrypt_info; struct seq_file; @@ -62,8 +62,7 @@ struct fscrypt_operations { int (*get_context)(struct inode *inode, void *ctx, size_t len); int (*set_context)(struct inode *inode, const void *ctx, size_t len, void *fs_data); - const union fscrypt_context *(*get_dummy_context)( - struct super_block *sb); + const union fscrypt_policy *(*get_dummy_policy)(struct super_block *sb); bool (*empty_dir)(struct inode *inode); unsigned int max_namelen; bool (*has_stable_inodes)(struct super_block *sb); @@ -101,14 +100,6 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode); } -static inline const union fscrypt_context * -fscrypt_get_dummy_context(struct super_block *sb) -{ - if (!sb->s_cop->get_dummy_context) - return NULL; - return sb->s_cop->get_dummy_context(sb); -} - /* * When d_splice_alias() moves a directory's encrypted alias to its decrypted * alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME @@ -158,20 +149,21 @@ int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg); int fscrypt_has_permitted_context(struct inode *parent, struct inode *child); int fscrypt_set_context(struct inode *inode, void *fs_data); -struct fscrypt_dummy_context { - const union fscrypt_context *ctx; +struct fscrypt_dummy_policy { + const union fscrypt_policy *policy; }; -int fscrypt_set_test_dummy_encryption(struct super_block *sb, - const substring_t *arg, - struct fscrypt_dummy_context *dummy_ctx); +int fscrypt_set_test_dummy_encryption( + struct super_block *sb, + const substring_t *arg, + struct fscrypt_dummy_policy *dummy_policy); void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, struct super_block *sb); static inline void -fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx) +fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) { - kfree(dummy_ctx->ctx); - dummy_ctx->ctx = NULL; + kfree(dummy_policy->policy); + dummy_policy->policy = NULL; } /* keyring.c */ @@ -250,12 +242,6 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) return false; } -static inline const union fscrypt_context * -fscrypt_get_dummy_context(struct super_block *sb) -{ - return NULL; -} - static inline void fscrypt_handle_d_move(struct dentry *dentry) { } @@ -346,7 +332,7 @@ static inline int fscrypt_set_context(struct inode *inode, void *fs_data) return -EOPNOTSUPP; } -struct fscrypt_dummy_context { +struct fscrypt_dummy_policy { }; static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq, @@ -356,7 +342,7 @@ static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq, } static inline void -fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx) +fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) { } From c8c868abc91ff23f6f5c4444c419de7c277d77e1 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:11:36 -0700 Subject: [PATCH 15/19] fscrypt: make fscrypt_set_test_dummy_encryption() take a 'const char *' fscrypt_set_test_dummy_encryption() requires that the optional argument to the test_dummy_encryption mount option be specified as a substring_t. That doesn't work well with filesystems that use the new mount API, since the new way of parsing mount options doesn't use substring_t. Make it take the argument as a 'const char *' instead. Instead of moving the match_strdup() into the callers in ext4 and f2fs, make them just use arg->from directly. Since the pattern is "test_dummy_encryption=%s", the argument will be null-terminated. Acked-by: Jeff Layton Link: https://lore.kernel.org/r/20200917041136.178600-14-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/policy.c | 20 ++++++-------------- fs/ext4/super.c | 2 +- fs/f2fs/super.c | 2 +- include/linux/fscrypt.h | 5 +---- 4 files changed, 9 insertions(+), 20 deletions(-) diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 97cf07543651..4441d9944b9e 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -697,8 +697,7 @@ EXPORT_SYMBOL_GPL(fscrypt_set_context); /** * fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption' * @sb: the filesystem on which test_dummy_encryption is being specified - * @arg: the argument to the test_dummy_encryption option. - * If no argument was specified, then @arg->from == NULL. + * @arg: the argument to the test_dummy_encryption option. May be NULL. * @dummy_policy: the filesystem's current dummy policy (input/output, see * below) * @@ -712,29 +711,23 @@ EXPORT_SYMBOL_GPL(fscrypt_set_context); * -EEXIST if a different dummy policy is already set; * or another -errno value. */ -int fscrypt_set_test_dummy_encryption(struct super_block *sb, - const substring_t *arg, +int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg, struct fscrypt_dummy_policy *dummy_policy) { - const char *argstr = "v2"; - const char *argstr_to_free = NULL; struct fscrypt_key_specifier key_spec = { 0 }; int version; union fscrypt_policy *policy = NULL; int err; - if (arg->from) { - argstr = argstr_to_free = match_strdup(arg); - if (!argstr) - return -ENOMEM; - } + if (!arg) + arg = "v2"; - if (!strcmp(argstr, "v1")) { + if (!strcmp(arg, "v1")) { version = FSCRYPT_POLICY_V1; key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR; memset(key_spec.u.descriptor, 0x42, FSCRYPT_KEY_DESCRIPTOR_SIZE); - } else if (!strcmp(argstr, "v2")) { + } else if (!strcmp(arg, "v2")) { version = FSCRYPT_POLICY_V2; key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER; /* key_spec.u.identifier gets filled in when adding the key */ @@ -785,7 +778,6 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb, err = 0; out: kfree(policy); - kfree(argstr_to_free); return err; } EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index aa6f64badf58..8b2736283481 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1892,7 +1892,7 @@ static int ext4_set_test_dummy_encryption(struct super_block *sb, "Can't set test_dummy_encryption on remount"); return -1; } - err = fscrypt_set_test_dummy_encryption(sb, arg, + err = fscrypt_set_test_dummy_encryption(sb, arg->from, &sbi->s_dummy_enc_policy); if (err) { if (err == -EEXIST) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index f05ee33f5f26..bef2be3fa3d0 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -438,7 +438,7 @@ static int f2fs_set_test_dummy_encryption(struct super_block *sb, return -EINVAL; } err = fscrypt_set_test_dummy_encryption( - sb, arg, &F2FS_OPTION(sbi).dummy_enc_policy); + sb, arg->from, &F2FS_OPTION(sbi).dummy_enc_policy); if (err) { if (err == -EEXIST) f2fs_warn(sbi, diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index b3b0c5675c6b..fc67c4cbaa96 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -15,7 +15,6 @@ #include #include -#include #include #include @@ -153,9 +152,7 @@ struct fscrypt_dummy_policy { const union fscrypt_policy *policy; }; -int fscrypt_set_test_dummy_encryption( - struct super_block *sb, - const substring_t *arg, +int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg, struct fscrypt_dummy_policy *dummy_policy); void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, struct super_block *sb); From 0c6a113b2446e7d4c6b8222fe63518dc2e01e8c1 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 16 Sep 2020 21:53:41 -0700 Subject: [PATCH 16/19] fscrypt: use sha256() instead of open coding Now that there's a library function that calculates the SHA-256 digest of a buffer in one step, use it instead of sha256_init() + sha256_update() + sha256_final(). Link: https://lore.kernel.org/r/20200917045341.324996-1-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fname.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index eb13408b50a7..f47b581d8a94 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -61,15 +61,6 @@ struct fscrypt_nokey_name { */ #define FSCRYPT_NOKEY_NAME_MAX offsetofend(struct fscrypt_nokey_name, sha256) -static void fscrypt_do_sha256(const u8 *data, unsigned int data_len, u8 *result) -{ - struct sha256_state sctx; - - sha256_init(&sctx); - sha256_update(&sctx, data, data_len); - sha256_final(&sctx, result); -} - static inline bool fscrypt_is_dot_dotdot(const struct qstr *str) { if (str->len == 1 && str->name[0] == '.') @@ -366,9 +357,9 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, } else { memcpy(nokey_name.bytes, iname->name, sizeof(nokey_name.bytes)); /* Compute strong hash of remaining part of name. */ - fscrypt_do_sha256(&iname->name[sizeof(nokey_name.bytes)], - iname->len - sizeof(nokey_name.bytes), - nokey_name.sha256); + sha256(&iname->name[sizeof(nokey_name.bytes)], + iname->len - sizeof(nokey_name.bytes), + nokey_name.sha256); size = FSCRYPT_NOKEY_NAME_MAX; } oname->len = base64_encode((const u8 *)&nokey_name, size, oname->name); @@ -497,7 +488,7 @@ bool fscrypt_match_name(const struct fscrypt_name *fname, { const struct fscrypt_nokey_name *nokey_name = (const void *)fname->crypto_buf.name; - u8 sha256[SHA256_DIGEST_SIZE]; + u8 digest[SHA256_DIGEST_SIZE]; if (likely(fname->disk_name.name)) { if (de_name_len != fname->disk_name.len) @@ -508,9 +499,9 @@ bool fscrypt_match_name(const struct fscrypt_name *fname, return false; if (memcmp(de_name, nokey_name->bytes, sizeof(nokey_name->bytes))) return false; - fscrypt_do_sha256(&de_name[sizeof(nokey_name->bytes)], - de_name_len - sizeof(nokey_name->bytes), sha256); - return !memcmp(sha256, nokey_name->sha256, sizeof(sha256)); + sha256(&de_name[sizeof(nokey_name->bytes)], + de_name_len - sizeof(nokey_name->bytes), digest); + return !memcmp(digest, nokey_name->sha256, sizeof(digest)); } EXPORT_SYMBOL_GPL(fscrypt_match_name); From 70fb2612aab62d47e03f82eaa7384a8d30ca175d Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 23 Sep 2020 21:26:23 -0700 Subject: [PATCH 17/19] fscrypt: don't call no-key names "ciphertext names" Currently we're using the term "ciphertext name" ambiguously because it can mean either the actual ciphertext filename, or the encoded filename that is shown when an encrypted directory is listed without its key. The latter we're now usually calling the "no-key name"; and while it's derived from the ciphertext name, it's not the same thing. To avoid this ambiguity, rename fscrypt_name::is_ciphertext_name to fscrypt_name::is_nokey_name, and update comments that say "ciphertext name" (or "encrypted name") to say "no-key name" instead when warranted. Link: https://lore.kernel.org/r/20200924042624.98439-2-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fname.c | 16 ++++++++-------- fs/crypto/hooks.c | 6 +++--- fs/f2fs/dir.c | 2 +- include/linux/fscrypt.h | 15 +++++++-------- 4 files changed, 19 insertions(+), 20 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index f47b581d8a94..391acea4bc96 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -382,9 +382,9 @@ EXPORT_SYMBOL(fscrypt_fname_disk_to_usr); * directory's encryption key, then @iname is the plaintext, so we encrypt it to * get the disk_name. * - * Else, for keyless @lookup operations, @iname is the presented ciphertext, so - * we decode it to get the fscrypt_nokey_name. Non-@lookup operations will be - * impossible in this case, so we fail them with ENOKEY. + * Else, for keyless @lookup operations, @iname should be a no-key name, so we + * decode it to get the struct fscrypt_nokey_name. Non-@lookup operations will + * be impossible in this case, so we fail them with ENOKEY. * * If successful, fscrypt_free_filename() must be called later to clean up. * @@ -429,7 +429,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, } if (!lookup) return -ENOKEY; - fname->is_ciphertext_name = true; + fname->is_nokey_name = true; /* * We don't have the key and we are doing a lookup; decode the @@ -538,17 +538,17 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) /* * Plaintext names are always valid, since fscrypt doesn't support - * reverting to ciphertext names without evicting the directory's inode + * reverting to no-key names without evicting the directory's inode * -- which implies eviction of the dentries in the directory. */ if (!(dentry->d_flags & DCACHE_ENCRYPTED_NAME)) return 1; /* - * Ciphertext name; valid if the directory's key is still unavailable. + * No-key name; valid if the directory's key is still unavailable. * - * Although fscrypt forbids rename() on ciphertext names, we still must - * use dget_parent() here rather than use ->d_parent directly. That's + * Although fscrypt forbids rename() on no-key names, we still must use + * dget_parent() here rather than use ->d_parent directly. That's * because a corrupted fs image may contain directory hard links, which * the VFS handles by moving the directory's dentry tree in the dcache * each time ->lookup() finds the directory and it already has a dentry diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 42f5ee9f592d..ca996e1c92d9 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -60,7 +60,7 @@ int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, if (err) return err; - /* ... in case we looked up ciphertext name before key was added */ + /* ... in case we looked up no-key name before key was added */ if (dentry->d_flags & DCACHE_ENCRYPTED_NAME) return -ENOKEY; @@ -85,7 +85,7 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, if (err) return err; - /* ... in case we looked up ciphertext name(s) before key was added */ + /* ... in case we looked up no-key name(s) before key was added */ if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_ENCRYPTED_NAME) return -ENOKEY; @@ -114,7 +114,7 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, if (err && err != -ENOENT) return err; - if (fname->is_ciphertext_name) { + if (fname->is_nokey_name) { spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_ENCRYPTED_NAME; spin_unlock(&dentry->d_lock); diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 414bc94fbd54..53fbc4dd6e48 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -111,7 +111,7 @@ static int __f2fs_setup_filename(const struct inode *dir, #ifdef CONFIG_FS_ENCRYPTION fname->crypto_buf = crypt_name->crypto_buf; #endif - if (crypt_name->is_ciphertext_name) { + if (crypt_name->is_nokey_name) { /* hash was decoded from the no-key name */ fname->hash = cpu_to_le32(crypt_name->hash); } else { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index fc67c4cbaa96..bc9ec727e993 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -35,7 +35,7 @@ struct fscrypt_name { u32 hash; u32 minor_hash; struct fscrypt_str crypto_buf; - bool is_ciphertext_name; + bool is_nokey_name; }; #define FSTR_INIT(n, l) { .name = n, .len = l } @@ -730,17 +730,16 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir, * @fname: (output) the name to use to search the on-disk directory * * Prepare for ->lookup() in a directory which may be encrypted by determining - * the name that will actually be used to search the directory on-disk. Lookups - * can be done with or without the directory's encryption key; without the key, - * filenames are presented in encrypted form. Therefore, we'll try to set up - * the directory's encryption key, but even without it the lookup can continue. + * the name that will actually be used to search the directory on-disk. If the + * directory's encryption key is available, then the lookup is assumed to be by + * plaintext name; otherwise, it is assumed to be by no-key name. * * This also installs a custom ->d_revalidate() method which will invalidate the * dentry if it was created without the key and the key is later added. * - * Return: 0 on success; -ENOENT if key is unavailable but the filename isn't a - * correctly formed encoded ciphertext name, so a negative dentry should be - * created; or another -errno code. + * Return: 0 on success; -ENOENT if the directory's key is unavailable but the + * filename isn't a valid no-key name, so a negative dentry should be created; + * or another -errno code. */ static inline int fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, From 501e43fbea468fa93c1dff0ee744e69303ef5a43 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 23 Sep 2020 21:26:24 -0700 Subject: [PATCH 18/19] fscrypt: rename DCACHE_ENCRYPTED_NAME to DCACHE_NOKEY_NAME Originally we used the term "encrypted name" or "ciphertext name" to mean the encoded filename that is shown when an encrypted directory is listed without its key. But these terms are ambiguous since they also mean the filename stored on-disk. "Encrypted name" is especially ambiguous since it could also be understood to mean "this filename is encrypted on-disk", similar to "encrypted file". So we've started calling these encoded names "no-key names" instead. Therefore, rename DCACHE_ENCRYPTED_NAME to DCACHE_NOKEY_NAME to avoid confusion about what this flag means. Link: https://lore.kernel.org/r/20200924042624.98439-3-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fname.c | 2 +- fs/crypto/hooks.c | 7 +++---- include/linux/dcache.h | 2 +- include/linux/fscrypt.h | 12 ++++++------ 4 files changed, 11 insertions(+), 12 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 391acea4bc96..c65979452844 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -541,7 +541,7 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) * reverting to no-key names without evicting the directory's inode * -- which implies eviction of the dentries in the directory. */ - if (!(dentry->d_flags & DCACHE_ENCRYPTED_NAME)) + if (!(dentry->d_flags & DCACHE_NOKEY_NAME)) return 1; /* diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index ca996e1c92d9..20b0df47fe6a 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -61,7 +61,7 @@ int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, return err; /* ... in case we looked up no-key name before key was added */ - if (dentry->d_flags & DCACHE_ENCRYPTED_NAME) + if (dentry->d_flags & DCACHE_NOKEY_NAME) return -ENOKEY; if (!fscrypt_has_permitted_context(dir, inode)) @@ -86,8 +86,7 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, return err; /* ... in case we looked up no-key name(s) before key was added */ - if ((old_dentry->d_flags | new_dentry->d_flags) & - DCACHE_ENCRYPTED_NAME) + if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME) return -ENOKEY; if (old_dir != new_dir) { @@ -116,7 +115,7 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, if (fname->is_nokey_name) { spin_lock(&dentry->d_lock); - dentry->d_flags |= DCACHE_ENCRYPTED_NAME; + dentry->d_flags |= DCACHE_NOKEY_NAME; spin_unlock(&dentry->d_lock); d_set_d_op(dentry, &fscrypt_d_ops); } diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 65d975bf9390..6f95c3300cbb 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -213,7 +213,7 @@ struct dentry_operations { #define DCACHE_MAY_FREE 0x00800000 #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ -#define DCACHE_ENCRYPTED_NAME 0x02000000 /* Encrypted name (dir key was unavailable) */ +#define DCACHE_NOKEY_NAME 0x02000000 /* Encrypted name encoded without key */ #define DCACHE_OP_REAL 0x04000000 #define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index bc9ec727e993..f1757e73162d 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -100,15 +100,15 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) } /* - * When d_splice_alias() moves a directory's encrypted alias to its decrypted - * alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME - * must be cleared. Note that we don't have to support arbitrary moves of this - * flag because fscrypt doesn't allow encrypted aliases to be the source or - * target of a rename(). + * When d_splice_alias() moves a directory's no-key alias to its plaintext alias + * as a result of the encryption key being added, DCACHE_NOKEY_NAME must be + * cleared. Note that we don't have to support arbitrary moves of this flag + * because fscrypt doesn't allow no-key names to be the source or target of a + * rename(). */ static inline void fscrypt_handle_d_move(struct dentry *dentry) { - dentry->d_flags &= ~DCACHE_ENCRYPTED_NAME; + dentry->d_flags &= ~DCACHE_NOKEY_NAME; } /* crypto.c */ From 5b2a828b98ec1872799b1b4d82113c76a12d594f Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 23 Sep 2020 22:47:21 -0700 Subject: [PATCH 19/19] fscrypt: export fscrypt_d_revalidate() Dentries that represent no-key names must have a dentry_operations that includes fscrypt_d_revalidate(). Currently, this is handled by fscrypt_prepare_lookup() installing fscrypt_d_ops. However, ceph support for encryption (https://lore.kernel.org/r/20200914191707.380444-1-jlayton@kernel.org) can't use fscrypt_d_ops, since ceph already has its own dentry_operations. Similarly, ext4 and f2fs support for directories that are both encrypted and casefolded (https://lore.kernel.org/r/20200923010151.69506-1-drosen@google.com) can't use fscrypt_d_ops either, since casefolding requires some dentry operations too. To satisfy both users, we need to move the responsibility of installing the dentry_operations to filesystems. In preparation for this, export fscrypt_d_revalidate() and give it a !CONFIG_FS_ENCRYPTION stub. Reviewed-by: Jeff Layton Link: https://lore.kernel.org/r/20200924054721.187797-1-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fname.c | 3 ++- include/linux/fscrypt.h | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index c65979452844..1fbe6c24d705 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -530,7 +530,7 @@ EXPORT_SYMBOL_GPL(fscrypt_fname_siphash); * Validate dentries in encrypted directories to make sure we aren't potentially * caching stale dentries after a key has been added. */ -static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) +int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) { struct dentry *dir; int err; @@ -569,6 +569,7 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) return valid; } +EXPORT_SYMBOL_GPL(fscrypt_d_revalidate); const struct dentry_operations fscrypt_d_ops = { .d_revalidate = fscrypt_d_revalidate, diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index f1757e73162d..a8f7a43f031b 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -197,6 +197,7 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, bool fscrypt_match_name(const struct fscrypt_name *fname, const u8 *de_name, u32 de_name_len); u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name); +int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags); /* bio.c */ void fscrypt_decrypt_bio(struct bio *bio); @@ -454,6 +455,12 @@ static inline u64 fscrypt_fname_siphash(const struct inode *dir, return 0; } +static inline int fscrypt_d_revalidate(struct dentry *dentry, + unsigned int flags) +{ + return 1; +} + /* bio.c */ static inline void fscrypt_decrypt_bio(struct bio *bio) {