mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-07-22 02:17:36 -04:00
Code Issues Packages Projects Releases Wiki Activity

perf symbols: Bounds-check descsz in sysfs__read_build_id() GNU fallback

Browse Source 
When sysfs__read_build_id() matches NT_GNU_BUILD_ID with the right
namesz but the name content is not "GNU", it falls back to reading
descsz bytes into the stack buffer bf[BUFSIZ]:

    } else if (read(fd, bf, descsz) != (ssize_t)descsz)

Unlike the else branch which validates namesz + descsz against
sizeof(bf), this path passes descsz directly to read() without any
bounds check.  A crafted sysfs file with a large n_descsz overflows
the 8192-byte stack buffer.

Add a descsz > sizeof(bf) check before the read, breaking out of
the loop on oversized values.

Fixes: e5a1845fc0 ("perf symbols: Split out util/symbol-elf.c")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo
2026-06-07 22:40:20 -03:00
parent e1a2c9d70b
commit 1b4e9fbdea
1 changed files with 7 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
tools/perf/util/symbol-elf.c
View File

@@ -961,8 +961,13 @@ int sysfs__read_build_id(const char *filename, struct build_id *bid)
err = 0;
break;
}
} else if (read(fd, bf, descsz) != (ssize_t)descsz)
break;
} else {
/* descsz from untrusted file — clamp to buffer */
if (descsz > sizeof(bf))
break;
if (read(fd, bf, descsz) != (ssize_t)descsz)
break;
}
} else {
size_t n;