perf header: Validate build_id filename length to prevent buffer overflow

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>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 9142a8ba401957c618ca15cf88c235dd10ac4971..9ffc0f4ca6d132daba499745b1b23062f7b83d2c 100644 (file)
--- 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 %zd\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 %zd\n", len);
+                       goto out;
+               }
+
                if (readn(input, filename, len) != len)
                        goto out;
                /*