[PATCH 4/5] perf jitdump: Size code_move event allocation with idr_size

[Arnaldo Carvalho de Melo <acme@kernel.org>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

jit_repipe_code_move() allocated the mmap2 event with a hardcoded
+16, but computes event->mmap2.header.size as sizeof(event->mmap2)
minus unused filename bytes plus idr_size.  When idr_size is larger
than 16, header.size exceeds the allocation, so perf_data__write()
reads past the heap allocation, leaking adjacent heap memory into the
generated perf.data file.

Size the allocation with idr_size like jit_repipe_code_load() does.

Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Assisted-by: LLM
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/jitdump.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index efb40d93e33ae664..689aa0a8c60bcd8b 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -636,9 +636,10 @@ static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr)
 	idr_size = jd->machine->id_hdr_size;
 
 	/*
-	 * +16 to account for sample_id_all (hack)
+	 * Sample ID is written past the end of the mmap2 record; size
+	 * the allocation to account for it instead of a hardcoded +16.
 	 */
-	event = calloc(1, sizeof(*event) + 16);
+	event = calloc(1, sizeof(*event) + idr_size);
 	if (!event)
 		return -1;
 
-- 
2.55.0