Messages in this thread Patch in this message | | | From | Colin Ian King <> | Subject | [PATCH][V2] selftests/resctrl: Fix null pointer dereference on open failed | Date | Tue, 26 Apr 2022 13:25:31 +0100 |
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Currently if opening /dev/null fails to open then file pointer fp is null and further access to fp via fprintf will cause a null pointer dereference. Fix this by returning a negative error value when a null fp is detected.
Detected using cppcheck static analysis: tools/testing/selftests/resctrl/fill_buf.c:124:6: note: Assuming that condition '!fp' is not redundant if (!fp) ^ tools/testing/selftests/resctrl/fill_buf.c:126:10: note: Null pointer dereference fprintf(fp, "Sum: %d ", ret);
Fixes: a2561b12fe39 ("selftests/resctrl: Add built in benchmark") Signed-off-by: Colin Ian King <colin.i.king@gmail.com> ---
V2: Add cppcheck analysis information
--- tools/testing/selftests/resctrl/fill_buf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c index 51e5cf22632f..56ccbeae0638 100644 --- a/tools/testing/selftests/resctrl/fill_buf.c +++ b/tools/testing/selftests/resctrl/fill_buf.c @@ -121,8 +121,10 @@ static int fill_cache_read(unsigned char *start_ptr, unsigned char *end_ptr, /* Consume read result so that reading memory is not optimized out. */ fp = fopen("/dev/null", "w"); - if (!fp) + if (!fp) { perror("Unable to write to /dev/null"); + return -1; + } fprintf(fp, "Sum: %d ", ret); fclose(fp); -- 2.35.1
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