tls: splice_read: fix accessing pre-processed records

mainline inclusion
from mainline-v5.16-rc3
commit e062fe99
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I56S5K?from=project-issue

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e062fe99cccd9ff9f232e593d163ecabd244fae8

--------------------------------

recvmsg() will put peek()ed and partially read records onto the rx_list.
splice_read() needs to consult that list otherwise it may miss data.
Align with recvmsg() and also put partially-read records onto rx_list.
tls_sw_advance_skb() is pretty pointless now and will be removed in
net-next.

Fixes: 692d7b5d ("tls: Fix recvmsg() to be able to peek across multiple records")
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Conflicts:
	net/tls/tls_sw.c
Signed-off-by: NZiyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/tls/tls_sw.c

@@ -2004,6 +2004,7 @@ 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;
@@ -2013,14 +2014,20 @@ 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;
+	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;
+		err = decrypt_skb_update(sk, skb, NULL, &chunk, &zc, false);
+		if (err < 0) {
+			tls_err_abort(sk, -EBADMSG);
+			goto splice_read_end;
+		}
 	}
 
 	/* splice does not support reading control messages */
@@ -2036,8 +2043,17 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	if (copied < 0)
 		goto splice_read_end;
 
-	if (likely(!(flags & MSG_PEEK)))
-		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);