[PATCH 4.19 013/264] net/tls: sendfile fails with ktls offload

[Greg Kroah-Hartman]

From: Rohit Maheshwari <rohitm@xxxxxxxxxxx>

[ Upstream commit ea1dd3e9d080c961b9a451130b61c72dc9a5397b ]

At first when sendpage gets called, if there is more data, 'more' in
tls_push_data() gets set which later sets pending_open_record_frags, but
when there is no more data in file left, and last time tls_push_data()
gets called, pending_open_record_frags doesn't get reset. And later when
2 bytes of encrypted alert comes as sendmsg, it first checks for
pending_open_record_frags, and since this is set, it creates a record with
0 data bytes to encrypt, meaning record length is prepend_size + tag_size
only, which causes problem.
 We should set/reset pending_open_record_frags based on more bit.

Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Rohit Maheshwari <rohitm@xxxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/tls/tls_device.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -351,13 +351,13 @@ static int tls_push_data(struct sock *sk
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
 	int tls_push_record_flags = flags | MSG_SENDPAGE_NOTLAST;
-	int more = flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE);
 	struct tls_record_info *record = ctx->open_record;
 	struct page_frag *pfrag;
 	size_t orig_size = size;
 	u32 max_open_record_len;
-	int copy, rc = 0;
+	bool more = false;
 	bool done = false;
+	int copy, rc = 0;
 	long timeo;
 
 	if (flags &
@@ -422,9 +422,8 @@ handle_error:
 		if (!size) {
 last_record:
 			tls_push_record_flags = flags;
-			if (more) {
-				tls_ctx->pending_open_record_frags =
-						record->num_frags;
+			if (flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE)) {
+				more = true;
 				break;
 			}
 
@@ -445,6 +444,8 @@ last_record:
 		}
 	} while (!done);
 
+	tls_ctx->pending_open_record_frags = more;
+
 	if (orig_size - size > 0)
 		rc = orig_size - size;