Patch "af_unix: Add sockaddr length checks before accessing sa_family in bind and connect handlers" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

af_unix: Add sockaddr length checks before accessing sa_family in bind and connect handlers

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
af_unix-add-sockaddr-length-checks-before-accessing-sa_family-in-bind-and-connect-handlers.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Mateusz Jurczyk <[email protected]>
Date: Thu, 8 Jun 2017 11:13:36 +0200
Subject: af_unix: Add sockaddr length checks before accessing sa_family in bind and connect handlers

From: Mateusz Jurczyk <[email protected]>

[ Upstream commit defbcf2decc903a28d8398aa477b6881e711e3ea ]

Verify that the caller-provided sockaddr structure is large enough to contain the sa_family field, before accessing it in bind() and connect() handlers of the AF_UNIX socket. Since neither syscall enforces a minimum size of the corresponding memory region, very short sockaddrs (zero or one byte long) result in operating on uninitialized memory while referencing .sa_family.

---
 net/unix/af_unix.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

@@ -998,7 +998,8 @@ static int unix_bind(struct socket *sock
 	struct path path = { NULL, NULL };
 
 	err = -EINVAL;
-	if (sunaddr->sun_family != AF_UNIX)
+	if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
+	    sunaddr->sun_family != AF_UNIX)
 		goto out;
 
 	if (addr_len == sizeof(short)) {

@@ -1109,6 +1110,10 @@ static int unix_dgram_connect(struct soc
 	unsigned int hash;
 	int err;
 
+	err = -EINVAL;
+	if (alen < offsetofend(struct sockaddr, sa_family))
+		goto out;
+
 	if (addr->sa_family != AF_UNSPEC) {
 		err = unix_mkname(sunaddr, alen, &hash);
 		if (err < 0)

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/decnet-dn_rtmsg-improve-input-length-sanitization-in-dnrmg_receive_user_skb.patch queue-4.9/af_unix-add-sockaddr-length-checks-before-accessing-sa_family-in-bind-and-connect-handlers.patch