[Quantal Precise CVE-2013-3076] crypto: algif - suppress sending source address information in recvmsg

[Luis Henriques]

From: Mathias Krause <minipli at googlemail.com>

CVE-2013-3076

BugLink: https://bugs.launchpad.net/bugs/1172363

The current code does not set the msg_namelen member to 0 and therefore
makes net/socket.c leak the local sockaddr_storage variable to userland
-- 128 bytes of kernel stack memory. Fix that.

Cc: <stable at vger.kernel.org> # 2.6.38
Signed-off-by: Mathias Krause <minipli at googlemail.com>
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
(cherry picked from commit 72a763d805a48ac8c0bf48fdb510e84c12de51fe)

Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 crypto/algif_hash.c     | 2 ++
 crypto/algif_skcipher.c | 1 +
 2 files changed, 3 insertions(+)

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index ef5356c..0262210 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -161,6 +161,8 @@ static int hash_recvmsg(struct kiocb *unused, struct socket *sock,
 	else if (len < ds)
 		msg->msg_flags |= MSG_TRUNC;
 
+	msg->msg_namelen = 0;
+
 	lock_sock(sk);
 	if (ctx->more) {
 		ctx->more = 0;
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 6a6dfc0..a1c4f0a 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -432,6 +432,7 @@ static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
 	long copied = 0;
 
 	lock_sock(sk);
+	msg->msg_namelen = 0;
 	for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;
 	     iovlen--, iov++) {
 		unsigned long seglen = iov->iov_len;
-- 
1.8.1.2