2020-07-25 18:19:08

by Gaurav Singh

Subject: [PATCH] [cgroup/testing] cg_read_strcmp: Fix null pointer dereference

Passing NULL in strcmp will cause a segmentation fault.
Fix this by returning -1 if expected is NULL pointer.

Signed-off-by: Gaurav Singh <[email protected]>
---
tools/testing/selftests/cgroup/cgroup_util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 8a637ca7d73a..05853b0b8831 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -106,7 +106,7 @@ int cg_read_strcmp(const char *cgroup, const char *control,

/* Handle the case of comparing against empty string */
if (!expected)
- size = 32;
+ return -1;
else
size = strlen(expected) + 1;

--
2.17.1

2020-07-25 20:25:58

by Chris Down

Subject: Re: [PATCH] [cgroup/testing] cg_read_strcmp: Fix null pointer dereference

Gaurav Singh writes:
>Passing NULL in strcmp will cause a segmentation fault.
>Fix this by returning -1 if expected is NULL pointer.

Did you actually encounter this while running the tests?

2020-07-26 01:42:19

by Gaurav Singh

Subject: [PATCH] [cgroup/testing] cg_read_strcmp: Fix null pointer dereference

Haven't reproduced this issue. This PR is does a minor code cleanup.

Signed-off-by: Gaurav Singh <[email protected]>
---
tools/testing/selftests/cgroup/cgroup_util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index 8a637ca7d73a..05853b0b8831 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -106,7 +106,7 @@ int cg_read_strcmp(const char *cgroup, const char *control,

/* Handle the case of comparing against empty string */
if (!expected)
- size = 32;
+ return -1;
else
size = strlen(expected) + 1;

--
2.17.1