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From: Sasha Levin <sasha.levin@oracle.com>
To: davem@davemloft.net
Cc: a.ryabinin@samsung.com, pablo@netfilter.org, mschmidt@redhat.com,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, Sasha Levin <sasha.levin@oracle.com>
Subject: [PATCH] netlink: don't copy over empty attribute data
Date: Tue, 21 Oct 2014 16:51:09 -0400	[thread overview]
Message-ID: <1413924669-26732-1-git-send-email-sasha.levin@oracle.com> (raw)

netlink uses empty data to seperate different levels. However, we still
try to copy that data from a NULL ptr using memcpy, which is an undefined
behaviour.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
 lib/nlattr.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/nlattr.c b/lib/nlattr.c
index 9c3e85f..6512b43 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -430,7 +430,8 @@ void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 	struct nlattr *nla;
 
 	nla = __nla_reserve(skb, attrtype, attrlen);
-	memcpy(nla_data(nla), data, attrlen);
+	if (data)
+		memcpy(nla_data(nla), data, attrlen);
 }
 EXPORT_SYMBOL(__nla_put);
 
-- 
1.7.10.4

             reply	other threads:[~2014-10-21 20:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-21 20:51 Sasha Levin [this message]
2014-10-22  1:39 ` [PATCH] netlink: don't copy over empty attribute data David Miller
2014-10-22  2:19   ` Sasha Levin
2014-10-22  6:15     ` David Miller
2014-10-26 23:32       ` Sasha Levin
2014-10-27  2:03         ` David Miller
2014-10-27 14:42           ` Sasha Levin
2014-10-27 16:46             ` Andrey Ryabinin
2014-10-22  8:55 ` David Laight

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