[PATCH v2] perf header: Validate build_id filename length to prevent buffer overflow

SeungJu Cheon
2026-04-01T21:53:36Z

The build_id parsing functions calculate a filename length from the
event header size and read directly into a stack buffer of PATH_MAX
bytes without bounds checking. A malformed perf.data file with a
crafted header.size can cause the length to be negative or exceed
PATH_MAX, resulting in a stack buffer overflow.

Add bounds checking for the filename length in both
perf_header__read_build_ids() and the ABI quirk variant. Print a
warning message when invalid length is detected.

Signed-off-by: SeungJu Cheon <suunj1331@gmail.com>
---
v2:
- Add warning message when invalid filename length detected
---
tools/perf/util/header.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 9142a8ba4019..132d360d716a 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2545,6 +2545,11 @@ static int perf_header__read_build_ids_abi_quirk(struct perf_header *header,
perf_event_header__bswap(&old_bev.header);

len = old_bev.header.size - sizeof(old_bev);
+ if (len < 0 || len >= PATH_MAX) {
+ pr_warning("invalid build_id filename length %d\n", len);
+ return -1;
+ }
+
if (readn(input, filename, len) != len)
return -1;

@@ -2587,6 +2592,11 @@ static int perf_header__read_build_ids(struct perf_header *header,
perf_event_header__bswap(&bev.header);

len = bev.header.size - sizeof(bev);
+ if (len < 0 || len >= PATH_MAX) {
+ pr_warning("invalid build_id filename length %d\n", len);
+ goto out;
+ }
+
if (readn(input, filename, len) != len)
goto out;
/*
--
2.52.0