From 6cf4b652443b20d2da44a1620a09ab8892a954f1 Mon Sep 17 00:00:00 2001 From: Yunfei Wang Date: Thu, 4 Nov 2021 19:10:12 +0800 Subject: [PATCH] FROMGIT: dma-buf: acquire name lock before read/write dma_buf.name MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Because dma-buf.name can be freed in func: "dma_buf_set_name", so, we need to acquire lock first before we read/write dma_buf.name to prevent Use After Free(UAF) issue. Signed-off-by: Guangming Cao Reviewed-by: Christian König Signed-off-by: Christian König Link: https://lore.kernel.org/lkml/20211029021541.101157-1-guangming.cao@mediatek.com/T/ Bug: 205102180 (cherry picked from commit 8c0fd126263730c35927cc8445727afb79219a19 https://cgit.freedesktop.org/drm/drm-misc) Change-Id: I4ba911137ad9dae7682230245d2fa2a19f7c209f Signed-off-by: Yunfei Wang --- drivers/dma-buf/dma-buf.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 0ee38382ba17..e4fdefbfe107 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1425,6 +1425,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) if (ret) goto error_unlock; + spin_lock(&buf_obj->name_lock); seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n", buf_obj->size, buf_obj->file->f_flags, buf_obj->file->f_mode, @@ -1432,6 +1433,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) buf_obj->exp_name, file_inode(buf_obj->file)->i_ino, buf_obj->name ?: ""); + spin_unlock(&buf_obj->name_lock); robj = buf_obj->resv; while (true) {