diff mbox series

[SRU,D,1/3] net/tls: fix lowat calculation if some data came from previous record

Message ID 20200722193402.358366-2-cascardo@canonical.com
State New
Headers show
Series [SRU,D,1/3] net/tls: fix lowat calculation if some data came from previous record | expand

Commit Message

Thadeu Lima de Souza Cascardo July 22, 2020, 7:34 p.m. UTC 
From: Jakub Kicinski <jakub.kicinski@netronome.com>

BugLink: https://bugs.launchpad.net/bugs/1888381

If some of the data came from the previous record, i.e. from
the rx_list it had already been decrypted, so it's not counted
towards the "decrypted" variable, but the "copied" variable.
Take that into account when checking lowat.

When calculating lowat target we need to pass the original len.
E.g. if lowat is at 80, len is 100 and we had 30 bytes on rx_list
target would currently be incorrectly calculated as 70, even though
we only need 50 more bytes to make up the 80.

Fixes: 692d7b5d1f91 ("tls: Fix recvmsg() to be able to peek across multiple records")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Tested-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 46a1695960d0600d58da7af33c65f24f3d839674)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---
 net/tls/tls_sw.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index e903b9f85108..b800e8b500e8 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1603,13 +1603,12 @@  int tls_sw_recvmsg(struct sock *sk,
 		copied = err;
 	}
 
-	len = len - copied;
-	if (len) {
-		target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
-		timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
-	} else {
+	if (len <= copied)
 		goto recv_end;
-	}
+
+	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
+	len = len - copied;
+	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 
 	do {
 		bool retain_skb = false;
@@ -1715,7 +1714,7 @@  int tls_sw_recvmsg(struct sock *sk,
 		}
 
 		/* If we have a new message from strparser, continue now. */
-		if (decrypted >= target && !ctx->recv_pkt)
+		if (decrypted + copied >= target && !ctx->recv_pkt)
 			break;
 	} while (len);