From: Tung Nguyen <tung.q.nguyen@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx>
Signed-off-by: Tung Nguyen <tung.q.nguyen@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230214012606.5804-1-tung.q.nguyen@xxxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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:
