David reported a buffer overflow error in the check_results() function of the cmt unit test and he suggested enabling _FORTIFY_SOURCE gcc compiler option to automatically detect any such errors.
Feature Test Macros man page describes_FORTIFY_SOURCE as below
"Defining this macro causes some lightweight checks to be performed to detect some buffer overflow errors when employing various string and memory manipulation functions (for example, memcpy, memset, stpcpy, strcpy, strncpy, strcat, strncat, sprintf, snprintf, vsprintf, vsnprintf, gets, and wide character variants thereof). For some functions, argument consistency is checked; for example, a check is made that open has been supplied with a mode argument when the specified flags include O_CREAT. Not all problems are detected, just some common cases.
If _FORTIFY_SOURCE is set to 1, with compiler optimization level 1 (gcc -O1) and above, checks that shouldn't change the behavior of conforming programs are performed.
With _FORTIFY_SOURCE set to 2, some more checking is added, but some conforming programs might fail.
Some of the checks can be performed at compile time (via macros logic implemented in header files), and result in compiler warnings; other checks take place at run time, and result in a run-time error if the check fails.
Use of this macro requires compiler support, available with gcc since version 4.0."
Fix the buffer overflow error in the check_results() function of the cmt unit test and enable _FORTIFY_SOURCE gcc check to catch any future buffer overflow errors.
Reported-by: David Binderman dcb314@hotmail.com Suggested-by: David Binderman dcb314@hotmail.com Tested-by: Babu Moger babu.moger@amd.com Signed-off-by: Fenghua Yu fenghua.yu@intel.com --- Change Log: v5: - Move from v4's patch 11 to patch 1 so the fix patch should be first (Shuah).
tools/testing/selftests/resctrl/Makefile | 2 +- tools/testing/selftests/resctrl/cqm_test.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/resctrl/Makefile b/tools/testing/selftests/resctrl/Makefile index d585cc1948cc..6bcee2ec91a9 100644 --- a/tools/testing/selftests/resctrl/Makefile +++ b/tools/testing/selftests/resctrl/Makefile @@ -1,5 +1,5 @@ CC = $(CROSS_COMPILE)gcc -CFLAGS = -g -Wall +CFLAGS = -g -Wall -O2 -D_FORTIFY_SOURCE=2 SRCS=$(wildcard *.c) OBJS=$(SRCS:.c=.o)
diff --git a/tools/testing/selftests/resctrl/cqm_test.c b/tools/testing/selftests/resctrl/cqm_test.c index c8756152bd61..5e7308ac63be 100644 --- a/tools/testing/selftests/resctrl/cqm_test.c +++ b/tools/testing/selftests/resctrl/cqm_test.c @@ -86,7 +86,7 @@ static int check_results(struct resctrl_val_param *param, int no_of_bits) return errno; }
- while (fgets(temp, 1024, fp)) { + while (fgets(temp, sizeof(temp), fp)) { char *token = strtok(temp, ":\t"); int fields = 0;