[PATCH V3 09/15] perf tools: validate perf event header size

From: Adrian Hunter
Date: Fri Jun 28 2013 - 04:38:18 EST


'size' includes the header so must be at least
'sizeof(struct perf_event_header)'. Error out
immediately if that is not the case. Also
don't byte-swap the header until it is actually
"fetched" from the mmap region.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/util/session.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 19ea888..7a12886 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1094,8 +1094,10 @@ more:
perf_event_header__bswap(&event->header);

size = event->header.size;
- if (size == 0)
- size = 8;
+ if (size < sizeof(struct perf_event_header)) {
+ pr_err("bad event header size\n");
+ goto out_err;
+ }

if (size > cur_size) {
void *new = realloc(buf, size);
@@ -1164,8 +1166,12 @@ fetch_mmaped_event(struct perf_session *session,
if (session->header.needs_swap)
perf_event_header__bswap(&event->header);

- if (head + event->header.size > mmap_size)
+ if (head + event->header.size > mmap_size) {
+ /* We're not fetching the event so swap back again */
+ if (session->header.needs_swap)
+ perf_event_header__bswap(&event->header);
return NULL;
+ }

return event;
}
@@ -1245,7 +1251,7 @@ more:

size = event->header.size;

- if (size == 0 ||
+ if (size < sizeof(struct perf_event_header) ||
perf_session__process_event(session, event, tool, file_pos) < 0) {
pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
file_offset + head, event->header.size,
--
1.7.11.7

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