[PATCH v4] tools/perf/util: null-terminate version char array upon error

[Donald Yandt]

If fgets fails due to any other error besides end-of-file, the version char array may not even be null-terminated.

Changes from v1-3:
 * close file, then return NULL instead of null-terminating version char array

Fixes: a1645ce12adb ("perf: 'perf kvm' tool for monitoring guest performance from host")
Signed-off-by: Donald Yandt <donald.yandt@xxxxxxxxx>
---
 tools/perf/util/machine.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 3c520baa1..6fd877220 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1234,9 +1234,10 @@ static char *get_kernel_version(const char *root_dir)
 	if (!file)
 		return NULL;

-	version[0] = '\0';
 	tmp = fgets(version, sizeof(version), file);
 	fclose(file);
+	if (!tmp)
+		return NULL;

 	name = strstr(version, prefix);
 	if (!name)
--
2.20.1