From d29f1f53e5299e0bbb3e33ef8d35ed657fa633b6 Mon Sep 17 00:00:00 2001 From: Ani Sinha Date: Mon, 8 Sep 2014 14:49:59 -0700 Subject: net:socket: set msg_namelen to 0 if msg_name is passed as NULL in msghdr struct from userland. commit 6a2a2b3ae0759843b22c929881cc184b00cc63ff upstream. Linux manpage for recvmsg and sendmsg calls does not explicitly mention setting msg_namelen to 0 when msg_name passed set as NULL. When developers don't set msg_namelen member in msghdr, it might contain garbage value which will fail the validation check and sendmsg and recvmsg calls from kernel will return EINVAL. This will break old binaries and any code for which there is no access to source code. To fix this, we set msg_namelen to 0 when msg_name is passed as NULL from userland. Signed-off-by: Ani Sinha Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/socket.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/socket.c') diff --git a/net/socket.c b/net/socket.c index 3faa358..116cf9d 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1885,6 +1885,9 @@ static int copy_msghdr_from_user(struct msghdr *kmsg, if (copy_from_user(kmsg, umsg, sizeof(struct msghdr))) return -EFAULT; + if (kmsg->msg_name == NULL) + kmsg->msg_namelen = 0; + if (kmsg->msg_namelen < 0) return -EINVAL; -- cgit v1.1