Patch "NFC: Add sockaddr length checks before accessing sa_family in bind handlers" has been added to the 4.4-stable tree

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

NFC: Add sockaddr length checks before accessing sa_family in bind handlers

to the 4.4-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:
nfc-add-sockaddr-length-checks-before-accessing-sa_family-in-bind-handlers.patch
and it can be found in the queue-4.4 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: Tue, 13 Jun 2017 18:44:28 +0200
Subject: NFC: Add sockaddr length checks before accessing sa_family in bind handlers

From: Mateusz Jurczyk <[email protected]>

commit f6a5885fc4d68e7f25ffb42b9d8d80aebb3bacbb upstream.

Verify that the caller-provided sockaddr structure is large enough to contain the sa_family field, before accessing it in bind() handlers of the AF_NFC socket. Since the syscall doesn't enforce 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/nfc/llcp_sock.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -76,7 +76,8 @@ static int llcp_sock_bind(struct socket
 	struct sockaddr_nfc_llcp llcp_addr;
 	int len, ret = 0;
 
-	if (!addr || addr->sa_family != AF_NFC)
+	if (!addr || alen < offsetofend(struct sockaddr, sa_family) ||
+	    addr->sa_family != AF_NFC)
 		return -EINVAL;
 
 	pr_debug("sk %p addr %p family %d\n", sk, addr, addr->sa_family);

@@ -150,7 +151,8 @@ static int llcp_raw_sock_bind(struct soc
 	struct sockaddr_nfc_llcp llcp_addr;
 	int len, ret = 0;
 
-	if (!addr || addr->sa_family != AF_NFC)
+	if (!addr || alen < offsetofend(struct sockaddr, sa_family) ||
+	    addr->sa_family != AF_NFC)
 		return -EINVAL;
 
 	pr_debug("sk %p addr %p family %d\n", sk, addr, addr->sa_family);

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

queue-4.4/nfc-add-sockaddr-length-checks-before-accessing-sa_family-in-bind-handlers.patch queue-4.4/nfc-ensure-presence-of-required-attributes-in-the-activate_target-handler.patch queue-4.4/nfc-fix-the-sockaddr-length-sanitization-in-llcp_sock_connect.patch