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

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Message-Id: <20190514205326.24287-1-donald.yandt@gmail.com>
Date:   Tue, 14 May 2019 16:53:26 -0400
From:   Donald Yandt <donald.yandt@...il.com>
To:     peterz@...radead.org
Cc:     mingo@...hat.com, acme@...nel.org,
        alexander.shishkin@...ux.intel.com, jolsa@...hat.com,
        yanmin_zhang@...ux.intel.com, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org, Donald Yandt <donald.yandt@...il.com>
Subject: [PATCH v4] tools/perf/util: null-terminate version char array upon error

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@...il.com>
---
 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