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From: Alexander Potapenko <glider@google.com>
To: dvyukov@google.com, kcc@google.com, davem@davemloft.net,
	akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] sysctl: don't read uninit memory in deprecated_sysctl_warning()
Date: Wed, 28 Jun 2017 17:00:37 +0200	[thread overview]
Message-ID: <20170628150037.3809-1-glider@google.com> (raw)

Don't attempt to read the first two elements of name[] unless they
were actually copied from the userspace.

This bug has been detected by KMSAN.

Signed-off-by: Alexander Potapenko <glider@google.com>
---
 kernel/sysctl_binary.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index ece4b177052b..38d6ba22a209 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1346,7 +1346,7 @@ static void deprecated_sysctl_warning(const int *name, int nlen)
 	 * CTL_KERN/KERN_VERSION is used by older glibc and cannot
 	 * ever go away.
 	 */
-	if (name[0] == CTL_KERN && name[1] == KERN_VERSION)
+	if (nlen >= 2 && name[0] == CTL_KERN && name[1] == KERN_VERSION)
 		return;
 
 	if (printk_ratelimit()) {
-- 
2.13.2.725.g09c95d1e9-goog

             reply	other threads:[~2017-06-28 15:00 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-28 15:00 Alexander Potapenko [this message]
2017-06-29 22:32 ` [PATCH] sysctl: don't read uninit memory in deprecated_sysctl_warning() Andrew Morton

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