[V2,12/19] selftests/resctrl: Enable gcc checks to detect buffer overflows
diff mbox series

Message ID a53033f871303fae931f9f170ec225dd07b639f6.1589835155.git.sai.praneeth.prakhya@intel.com
State New
Headers show
Series
  • Miscellaneous fixes for resctrl selftests
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Commit Message

Prakhya, Sai Praneeth May 18, 2020, 10:08 p.m. UTC
Feature Test Macros man page says the below about _FORTIFY_SOURCE

"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."

Enable this gcc check to catch buffer overflow bugs like the one in CMT
test.

Fixes: 78941183d1b1 ("selftests/resctrl: Add Cache QoS Monitoring (CQM) selftest")
Reported-by: David Binderman <dcb314@hotmail.com>
Suggested-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
---
 tools/testing/selftests/resctrl/Makefile   | 2 +-
 tools/testing/selftests/resctrl/cmt_test.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Patch
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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/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
index 6ffb56c6a1e2..282ba7fcf17c 100644
--- a/tools/testing/selftests/resctrl/cmt_test.c
+++ b/tools/testing/selftests/resctrl/cmt_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;