tls: Stricter error checking in zerocopy sendmsg path

commit 32da12216e467dea70a09cd7094c30779ce0f9db upstream.

In the zerocopy sendmsg() path, there are error checks to revert
the zerocopy if we get any error code.  syzkaller has discovered
that tls_push_record can return -ECONNRESET, which is fatal, and
happens after the point at which it is safe to revert the iter,
as we've already passed the memory to do_tcp_sendpages.

Previously this code could return -ENOMEM and we would want to
revert the iter, but AFAIK this no longer returns ENOMEM after
a447da7d004 ("tls: fix waitall behavior in tls_sw_recvmsg"),
so we fail for all error codes.

Reported-by: syzbot+c226690f7b3126c5ee04@syzkaller.appspotmail.com
Reported-by: syzbot+709f2810a6a05f11d4d3@syzkaller.appspotmail.com
Signed-off-by: Dave Watson <davejwatson@fb.com>
Fixes: 3c4d7559159b ("tls: kernel TLS support")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dave Watson 2018-07-12 08:03:43 -07:00 committed by Greg Kroah-Hartman
parent d9bb71d76c
commit 30a7a7b04f

View File

@ -449,7 +449,7 @@ alloc_encrypted:
ret = tls_push_record(sk, msg->msg_flags, record_type);
if (!ret)
continue;
if (ret == -EAGAIN)
if (ret < 0)
goto send_end;
copied -= try_to_copy;