4.17-stable review patch. If anyone has any objections, please let me know.
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From: Dave Watson davejwatson@fb.com
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
--- net/tls/tls_sw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -440,7 +440,7 @@ 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;