From: Tung Nguyen tung.q.nguyen@dektech.com.au
commit 11a4d6f67cf55883dc78e31c247d1903ed7feccc upstream.
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] <TASK> [ 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 jmaloy@redhat.com Signed-off-by: Tung Nguyen tung.q.nguyen@dektech.com.au Link: https://lore.kernel.org/r/20230214012606.5804-1-tung.q.nguyen@dektech.com.au Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/tipc/socket.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -2614,6 +2614,7 @@ static int tipc_connect(struct socket *s /* 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 *so __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: