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lib/buildid: don't limit .note.gnu.build-id to the first page in ELF

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With freader we don't need to restrict ourselves to a single page, so
let's allow ELF notes to be at any valid position with the file.

We also merge parse_build_id() and parse_build_id_buf() as now the only
difference between them is note offset overflow, which makes sense to
check in all situations.

Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-8-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko
2024-08-29 10:42:29 -07:00
committed by Alexei Starovoitov
parent ad41251c29
commit cdbb44f9a7
1 changed files with 5 additions and 21 deletions
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lib/buildid.c
+5 -21
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@@ -155,9 +155,8 @@ static void freader_cleanup(struct freader *r)
* 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
* identical. * identical.
*/ */
static int parse_build_id_buf(struct freader *r, static int parse_build_id(struct freader *r, unsigned char *build_id, __u32 *size,
unsigned char *build_id, __u32 *size, loff_t note_off, Elf32_Word note_size)
loff_t note_off, Elf32_Word note_size)
{ {
const char note_name[] = "GNU"; const char note_name[] = "GNU";
const size_t note_name_sz = sizeof(note_name); const size_t note_name_sz = sizeof(note_name);
@@ -165,7 +164,9 @@ static int parse_build_id_buf(struct freader *r,
const Elf32_Nhdr *nhdr; const Elf32_Nhdr *nhdr;
const char *data; const char *data;
note_end = note_off + note_size; if (check_add_overflow(note_off, note_size, &note_end))
return -EINVAL;
while (note_end - note_off > sizeof(Elf32_Nhdr) + note_name_sz) { while (note_end - note_off > sizeof(Elf32_Nhdr) + note_name_sz) {
nhdr = freader_fetch(r, note_off, sizeof(Elf32_Nhdr) + note_name_sz); nhdr = freader_fetch(r, note_off, sizeof(Elf32_Nhdr) + note_name_sz);
if (!nhdr) if (!nhdr)
@@ -204,23 +205,6 @@ static int parse_build_id_buf(struct freader *r,
return -EINVAL; return -EINVAL;
} }
static inline int parse_build_id(struct freader *r,
unsigned char *build_id,
__u32 *size,
loff_t note_start_off,
Elf32_Word note_size)
{
/* check for overflow */
if (note_start_off + note_size < note_start_off)
return -EINVAL;
/* only supports note that fits in the first page */
if (note_start_off + note_size > PAGE_SIZE)
return -EINVAL;
return parse_build_id_buf(r, build_id, size, note_start_off, note_size);
}
/* Parse build ID from 32-bit ELF */ /* Parse build ID from 32-bit ELF */
static int get_build_id_32(struct freader *r, unsigned char *build_id, __u32 *size) static int get_build_id_32(struct freader *r, unsigned char *build_id, __u32 *size)
{ {