* [PATCH][next] perf tests: fix out of bounds access on array fd when cnt is 100
@ 2018-03-14 17:33 Colin King
2018-03-14 19:00 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 2+ messages in thread
From: Colin King @ 2018-03-14 17:33 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Alexander Shishkin, Jiri Olsa, Namhyung Kim
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Currently when cnt is 100 an array bounds overflow occurs on the assignment
of fd[cnt]. Fix this by performing the bounds check on cnt before writing
to fd.
Detected by cppcheck:
tools/perf/tests/bp_account.c:115: (warning) Either the condition
'cnt=100' is redundant or the array 'fd[100]' is accessed at index 100,
which is out of bounds.
Fixes: 032db28e5fa3 ("perf tests: Add breakpoint accounting/modify test")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
tools/perf/tests/bp_account.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/tools/perf/tests/bp_account.c b/tools/perf/tests/bp_account.c
index 2f75fa0c4fef..9e88d7608951 100644
--- a/tools/perf/tests/bp_account.c
+++ b/tools/perf/tests/bp_account.c
@@ -107,16 +107,14 @@ static int detect_cnt(bool is_x)
int fd[100], cnt = 0, i;
while (1) {
- fd[cnt] = __event(is_x, addr, &attr);
-
- if (fd[cnt] < 0)
- break;
-
if (cnt = 100) {
pr_debug("way too many debug registers, fix the test\n");
return 0;
}
+ fd[cnt] = __event(is_x, addr, &attr);
+ if (fd[cnt] < 0)
+ break;
cnt++;
}
--
2.15.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH][next] perf tests: fix out of bounds access on array fd when cnt is 100
2018-03-14 17:33 [PATCH][next] perf tests: fix out of bounds access on array fd when cnt is 100 Colin King
@ 2018-03-14 19:00 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 2+ messages in thread
From: Arnaldo Carvalho de Melo @ 2018-03-14 19:00 UTC (permalink / raw)
To: Colin King
Cc: Peter Zijlstra, Ingo Molnar, Alexander Shishkin, Jiri Olsa,
Namhyung Kim, kernel-janitors, linux-kernel
Em Wed, Mar 14, 2018 at 05:33:54PM +0000, Colin King escreveu:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently when cnt is 100 an array bounds overflow occurs on the assignment
> of fd[cnt]. Fix this by performing the bounds check on cnt before writing
> to fd.
>
> Detected by cppcheck:
> tools/perf/tests/bp_account.c:115: (warning) Either the condition
> 'cnt=100' is redundant or the array 'fd[100]' is accessed at index 100,
> which is out of bounds.
>
> Fixes: 032db28e5fa3 ("perf tests: Add breakpoint accounting/modify test")
Thanks, applied.
- Arnaldo
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