netdev - [PATCH net-next] net/tls: Do not use async crypto for non-data records

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Date:   Mon, 11 Feb 2019 11:31:05 +0000
From:   Vakul Garg <vakul.garg@....com>
To:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     "borisp@...lanox.com" <borisp@...lanox.com>,
        "aviadye@...lanox.com" <aviadye@...lanox.com>,
        "davejwatson@...com" <davejwatson@...com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "doronrk@...com" <doronrk@...com>, Vakul Garg <vakul.garg@....com>
Subject: [PATCH net-next] net/tls: Do not use async crypto for non-data
 records

Addition of tls1.3 support broke tls1.2 handshake when async crypto
accelerator is used. This is because the record type for non-data
records is not propagated to user application. Also when async
decryption happens, the decryption does not stop when two different
types of records get dequeued and submitted for decryption. To address
it, we decrypt tls1.2 non-data records in synchronous way. We check
whether the record we just processed has same type as the previous one
before checking for async condition and jumping to dequeue next record.

Fixes: 130b392c6cd6b ("net: tls: Add tls 1.3 support")
Signed-off-by: Vakul Garg <vakul.garg@....com>
---
 net/tls/tls_sw.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index fe8c287cbaa1..ae4784734547 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1645,10 +1645,10 @@ int tls_sw_recvmsg(struct sock *sk,
 
 	do {
 		bool retain_skb = false;
-		bool async = false;
 		bool zc = false;
 		int to_decrypt;
 		int chunk = 0;
+		bool async;
 
 		skb = tls_wait_data(sk, psock, flags, timeo, &err);
 		if (!skb) {
@@ -1674,18 +1674,21 @@ int tls_sw_recvmsg(struct sock *sk,
 		    tls_ctx->crypto_recv.info.version != TLS_1_3_VERSION)
 			zc = true;
 
+		/* Do not use async mode if record is non-data */
+		if (ctx->control == TLS_RECORD_TYPE_DATA)
+			async = ctx->async_capable;
+		else
+			async = false;
+
 		err = decrypt_skb_update(sk, skb, &msg->msg_iter,
-					 &chunk, &zc, ctx->async_capable);
+					 &chunk, &zc, async);
 		if (err < 0 && err != -EINPROGRESS) {
 			tls_err_abort(sk, EBADMSG);
 			goto recv_end;
 		}
 
-		if (err == -EINPROGRESS) {
-			async = true;
+		if (err == -EINPROGRESS)
 			num_async++;
-			goto pick_next_record;
-		}
 
 		if (!cmsg) {
 			int cerr;
@@ -1704,6 +1707,9 @@ int tls_sw_recvmsg(struct sock *sk,
 			goto recv_end;
 		}
 
+		if (async)
+			goto pick_next_record;
+
 		if (!zc) {
 			if (rxm->full_len > len) {
 				retain_skb = true;
-- 
2.13.6