From: Jakub Kicinski Date: Fri, 24 May 2019 17:34:32 +0000 (-0700) Subject: net/tls: fix no wakeup on partial reads X-Git-Tag: v5.2-rc3~26^2~25^2~1 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=04b25a5411f966c2e586909a8496553b71876fae;p=linux.git net/tls: fix no wakeup on partial reads When tls_sw_recvmsg() partially copies a record it pops that record from ctx->recv_pkt and places it on rx_list. Next iteration of tls_sw_recvmsg() reads from rx_list via process_rx_list() before it enters the decryption loop. If there is no more records to be read tls_wait_data() will put the process on the wait queue and got to sleep. This is incorrect, because some data was already copied in process_rx_list(). In case of RPC connections process may never get woken up, because peer also simply blocks in read(). I think this may also fix a similar issue when BPF is at play, because after __tcp_bpf_recvmsg() returns some data we subtract it from len and use continue to restart the loop, but len could have just reached 0, so again we'd sleep unnecessarily. That's added by: commit d3b18ad31f93 ("tls: add bpf support to sk_msg handling") Fixes: 692d7b5d1f91 ("tls: Fix recvmsg() to be able to peek across multiple records") Reported-by: David Beckett Signed-off-by: Jakub Kicinski Reviewed-by: Dirk van der Merwe Tested-by: David Beckett Signed-off-by: David S. Miller --- diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index fc13234db74a..960494f437ac 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1719,7 +1719,7 @@ int tls_sw_recvmsg(struct sock *sk, len = len - copied; timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); - do { + while (len && (decrypted + copied < target || ctx->recv_pkt)) { bool retain_skb = false; bool zc = false; int to_decrypt; @@ -1850,11 +1850,7 @@ int tls_sw_recvmsg(struct sock *sk, } else { break; } - - /* If we have a new message from strparser, continue now. */ - if (decrypted + copied >= target && !ctx->recv_pkt) - break; - } while (len); + } recv_end: if (num_async) {