From 11a4d6f67cf55883dc78e31c247d1903ed7feccc Mon Sep 17 00:00:00 2001 From: Tung Nguyen Date: Tue, 14 Feb 2023 01:26:06 +0000 Subject: tipc: fix kernel warning when sending SYN message When sending a SYN message, this kernel stack trace is observed: ... [ 13.396352] RIP: 0010:_copy_from_iter+0xb4/0x550 ... [ 13.398494] Call Trace: [ 13.398630] [ 13.398630] ? __alloc_skb+0xed/0x1a0 [ 13.398630] tipc_msg_build+0x12c/0x670 [tipc] [ 13.398630] ? shmem_add_to_page_cache.isra.71+0x151/0x290 [ 13.398630] __tipc_sendmsg+0x2d1/0x710 [tipc] [ 13.398630] ? tipc_connect+0x1d9/0x230 [tipc] [ 13.398630] ? __local_bh_enable_ip+0x37/0x80 [ 13.398630] tipc_connect+0x1d9/0x230 [tipc] [ 13.398630] ? __sys_connect+0x9f/0xd0 [ 13.398630] __sys_connect+0x9f/0xd0 [ 13.398630] ? preempt_count_add+0x4d/0xa0 [ 13.398630] ? fpregs_assert_state_consistent+0x22/0x50 [ 13.398630] __x64_sys_connect+0x16/0x20 [ 13.398630] do_syscall_64+0x42/0x90 [ 13.398630] entry_SYSCALL_64_after_hwframe+0x63/0xcd It is because commit a41dad905e5a ("iov_iter: saner checks for attempt to copy to/from iterator") has introduced sanity check for copying from/to iov iterator. Lacking of copy direction from the iterator viewpoint would lead to kernel stack trace like above. This commit fixes this issue by initializing the iov iterator with the correct copy direction when sending SYN or ACK without data. Fixes: f25dcc7687d4 ("tipc: tipc ->sendmsg() conversion") Reported-by: syzbot+d43608d061e8847ec9f3@syzkaller.appspotmail.com Acked-by: Jon Maloy Signed-off-by: Tung Nguyen Link: https://lore.kernel.org/r/20230214012606.5804-1-tung.q.nguyen@dektech.com.au Signed-off-by: Jakub Kicinski --- net/tipc/socket.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/tipc') diff --git a/net/tipc/socket.c b/net/tipc/socket.c index b35c8701876a..a38733f2197a 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -2614,6 +2614,7 @@ static int tipc_connect(struct socket *sock, struct sockaddr *dest, /* Send a 'SYN-' to destination */ m.msg_name = dest; m.msg_namelen = destlen; + iov_iter_kvec(&m.msg_iter, ITER_SOURCE, NULL, 0, 0); /* If connect is in non-blocking case, set MSG_DONTWAIT to * indicate send_msg() is never blocked. @@ -2776,6 +2777,7 @@ static int tipc_accept(struct socket *sock, struct socket *new_sock, int flags, __skb_queue_head(&new_sk->sk_receive_queue, buf); skb_set_owner_r(buf, new_sk); } + iov_iter_kvec(&m.msg_iter, ITER_SOURCE, NULL, 0, 0); __tipc_sendstream(new_sock, &m, 0); release_sock(new_sk); exit: -- cgit