[PATCH AUTOSEL for 4.15 032/189] perf record: Fix failed memory allocation for get_cpuid_str

[Sasha Levin]

From: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 81fccd6ca507d3b2012eaf1edeb9b1dbf4bd22db ]

In x86 architecture dependend part function get_cpuid_str() mallocs a
128 byte buffer, but does not check if the memory allocation succeeded
or not.

When the memory allocation fails, function __get_cpuid() is called with
first parameter being a NULL pointer.  However this function references
its first parameter and operates on a NULL pointer which might cause
core dumps.

Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180117131611.34319-1-tmricht@xxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 tools/perf/arch/x86/util/header.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/arch/x86/util/header.c b/tools/perf/arch/x86/util/header.c
index 33027c5e6f92..c6b5204e0280 100644
--- a/tools/perf/arch/x86/util/header.c
+++ b/tools/perf/arch/x86/util/header.c
@@ -70,7 +70,7 @@ get_cpuid_str(void)
 {
 	char *buf = malloc(128);
 
-	if (__get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
+	if (buf && __get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
 		free(buf);
 		return NULL;
 	}
-- 
2.15.1