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

af_key: fix buffer overread in verify_address_len()

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: af_key-fix-buffer-overread-in-verify_address_len.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 stable@vger.kernel.org know about it.

From 06b335cb51af018d5feeff5dd4fd53847ddb675a Mon Sep 17 00:00:00 2001

From: Eric Biggers ebiggers@google.com Date: Fri, 29 Dec 2017 18:13:05 -0600 Subject: af_key: fix buffer overread in verify_address_len()

From: Eric Biggers ebiggers@google.com

commit 06b335cb51af018d5feeff5dd4fd53847ddb675a upstream.

If a message sent to a PF_KEY socket ended with one of the extensions that takes a 'struct sadb_address' but there were not enough bytes remaining in the message for the ->sa_family member of the 'struct sockaddr' which is supposed to follow, then verify_address_len() read past the end of the message, into uninitialized memory. Fix it by returning -EINVAL in this case.

This bug was found using syzkaller with KMSAN.

Reproducer:

#include <linux/pfkeyv2.h> #include <sys/socket.h> #include <unistd.h>

int main() { int sock = socket(PF_KEY, SOCK_RAW, PF_KEY_V2); char buf[24] = { 0 }; struct sadb_msg *msg = (void *)buf; struct sadb_address *addr = (void *)(msg + 1);

msg->sadb_msg_version = PF_KEY_V2; msg->sadb_msg_type = SADB_DELETE; msg->sadb_msg_len = 3; addr->sadb_address_len = 1; addr->sadb_address_exttype = SADB_EXT_ADDRESS_SRC;

write(sock, buf, 24); }

Reported-by: Alexander Potapenko glider@google.com Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/key/af_key.c | 5 +++++ 1 file changed, 5 insertions(+)

--- a/net/key/af_key.c +++ b/net/key/af_key.c @@ -401,6 +401,11 @@ static int verify_address_len(const void #endif int len;

+ if (sp->sadb_address_len < + DIV_ROUND_UP(sizeof(*sp) + offsetofend(typeof(*addr), sa_family), + sizeof(uint64_t))) + return -EINVAL; + switch (addr->sa_family) { case AF_INET: len = DIV_ROUND_UP(sizeof(*sp) + sizeof(*sin), sizeof(uint64_t));

Patches currently in stable-queue which might be from ebiggers@google.com are

queue-4.4/af_key-fix-buffer-overread-in-parse_exthdrs.patch queue-4.4/af_key-fix-buffer-overread-in-verify_address_len.patch