Merge branch 'tls-splice_read-fixes'

Jakub Kicinski says:

====================
tls: splice_read fixes

As I work my way to unlocked and zero-copy TLS Rx the obvious bugs
in the splice_read implementation get harder and harder to ignore.
This is to say the fixes here are discovered by code inspection,
I'm not aware of anyone actually using splice_read.
====================

Link: https://lore.kernel.org/r/20211124232557.2039757-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 27 insertions, 13 deletions

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index d81564078557..d3e7ff90889e 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2005,6 +2005,7 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	struct sock *sk = sock->sk;
 	struct sk_buff *skb;
 	ssize_t copied = 0;
+	bool from_queue;
 	int err = 0;
 	long timeo;
 	int chunk;
@@ -2014,25 +2015,28 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 
 	timeo = sock_rcvtimeo(sk, flags & SPLICE_F_NONBLOCK);
 
-	skb = tls_wait_data(sk, NULL, flags & SPLICE_F_NONBLOCK, timeo, &err);
-	if (!skb)
-		goto splice_read_end;
-
-	if (!ctx->decrypted) {
-		err = decrypt_skb_update(sk, skb, NULL, &chunk, &zc, false);
-
-		/* splice does not support reading control messages */
-		if (ctx->control != TLS_RECORD_TYPE_DATA) {
-			err = -EINVAL;
+	from_queue = !skb_queue_empty(&ctx->rx_list);
+	if (from_queue) {
+		skb = __skb_dequeue(&ctx->rx_list);
+	} else {
+		skb = tls_wait_data(sk, NULL, flags & SPLICE_F_NONBLOCK, timeo,
+				    &err);
+		if (!skb)
 			goto splice_read_end;
-		}
 
+		err = decrypt_skb_update(sk, skb, NULL, &chunk, &zc, false);
 		if (err < 0) {
 			tls_err_abort(sk, -EBADMSG);
 			goto splice_read_end;
 		}
-		ctx->decrypted = 1;
 	}
+
+	/* splice does not support reading control messages */
+	if (ctx->control != TLS_RECORD_TYPE_DATA) {
+		err = -EINVAL;
+		goto splice_read_end;
+	}
+
 	rxm = strp_msg(skb);
 
 	chunk = min_t(unsigned int, rxm->full_len, len);
@@ -2040,7 +2044,17 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	if (copied < 0)
 		goto splice_read_end;
 
-	tls_sw_advance_skb(sk, skb, copied);
+	if (!from_queue) {
+		ctx->recv_pkt = NULL;
+		__strp_unpause(&ctx->strp);
+	}
+	if (chunk < rxm->full_len) {
+		__skb_queue_head(&ctx->rx_list, skb);
+		rxm->offset += len;
+		rxm->full_len -= len;
+	} else {
+		consume_skb(skb);
+	}
 
 splice_read_end:
 	release_sock(sk);