tools lib traceevent: Fix buffer overflow in arg_eval

Fix buffer overflow observed when running perf test.

The overflow is when trying to evaluate "1ULL << (64 - 1)" which is resulting in -9223372036854775808 which overflows the 20 character buffer.

If is possible this bug has been reported before but I still don't see any fix checked in:

See: https://www.spinics.net/lists/linux-perf-users/msg07714.html

Cc Arnaldo Carvalho de Melo <[email protected]>

Cc [email protected]

Cc Steven Rostedt <[email protected]>

Signed-off-by Tony Jones <[email protected]>

---
 tools/lib/traceevent/event-parse.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(quoted diff) +0 -0

b/tools/lib/traceevent/event-parse.c index abd4fa5d3088..87494c7c619d 100644 --- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c

tools/lib/traceevent/event-parse.c +1 -1

@@ -2457,7 +2457,7 @@ static int arg_num_eval(struct tep_print_arg
 *arg, long long *val) static char *arg_eval (struct tep_print_arg
 *arg) {
 	long long val;
-	static char buf[20];
+	static char buf[24];
 
 	switch (arg->type) {
 	case TEP_PRINT_ATOM:

Quoted 9 lines · On Wed, 27 Feb 2019 17:55:32 -0800 Tony Jones <[email protected]> wrote:

Fix buffer overflow observed when running perf test.

The overflow is when trying to evaluate "1ULL << (64 - 1)" which is resulting in -9223372036854775808 which overflows the 20 character buffer.

If is possible this bug has been reported before but I still don't see any fix checked in:

Quoted 6 lines

See: https://www.spinics.net/lists/linux-perf-users/msg07714.html

Cc Arnaldo Carvalho de Melo <[email protected]>

Cc [email protected]

Cc Steven Rostedt <[email protected]>

Signed-off-by Tony Jones <[email protected]>

Acked-by Steven Rostedt (VMware) <[email protected]>

I have to say I've let this slide and it is not the first time a patch went out with this fix. But this one has the correct fix because we should use a buffer with a multiple of 4. Anyway, Tony I believe was the first to report this anyway.

For reference we have:

I first heard about Tony's complaint on a post to linux-perf-users on Jan 18.

But then we had after that:

Michael Sartain reported it on 1/24 (and fixed by Tzvetomir)
https://lore.kernel.org/linux-trace-devel/[email protected]/

It was later fixed again by Mathias Krause
https://lore.kernel.org/linux-trace-devel/[email protected]/

But since Tony was first to report it, and we discussed that it should be 24 bytes, I would say this is the patch to take.

Again, sorry for not getting this acknowledged earlier and everyone doing the same thing multiple times. :-/

Arnaldo, please take this patch. But also add:

Reported-by Michael Sartain <[email protected]>

Reported-by Mathias Krause <[email protected]>

Em Wed, Feb 27, 2019 at 10:12:50PM -0500, Steven Rostedt escreveu:

Quoted 44 lines

Quoted 9 lines · On Wed, 27 Feb 2019 17:55:32 -0800 Tony Jones <[email protected]> wrote:

Fix buffer overflow observed when running perf test.

The overflow is when trying to evaluate "1ULL << (64 - 1)" which is resulting in -9223372036854775808 which overflows the 20 character buffer.

If is possible this bug has been reported before but I still don't see any fix checked in:

Quoted 6 lines

See: https://www.spinics.net/lists/linux-perf-users/msg07714.html

Cc Arnaldo Carvalho de Melo <[email protected]>

Cc [email protected]

Cc Steven Rostedt <[email protected]>

Signed-off-by Tony Jones <[email protected]>

Acked-by Steven Rostedt (VMware) <[email protected]>

I have to say I've let this slide and it is not the first time a patch went out with this fix. But this one has the correct fix because we should use a buffer with a multiple of 4. Anyway, Tony I believe was the first to report this anyway.

For reference we have:

I first heard about Tony's complaint on a post to linux-perf-users on Jan 18.

But then we had after that:

Michael Sartain reported it on 1/24 (and fixed by Tzvetomir)
https://lore.kernel.org/linux-trace-devel/[email protected]/

It was later fixed again by Mathias Krause
https://lore.kernel.org/linux-trace-devel/[email protected]/

But since Tony was first to report it, and we discussed that it should be 24 bytes, I would say this is the patch to take.

Again, sorry for not getting this acknowledged earlier and everyone doing the same thing multiple times. :-/

Quoted 4 lines

Arnaldo, please take this patch. But also add:

Reported-by Michael Sartain <[email protected]>

Reported-by Mathias Krause <[email protected]>

Will do.

Thanks for the credit research,