linux-kernel - [PATCH 3.12 029/101] macvtap: Fix csum

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed,  3 Dec 2014 12:25:51 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Jiri Slaby <jslaby@...e.cz>,
	"David S. Miller" <davem@...emloft.net>
Subject: [PATCH 3.12 029/101] macvtap: Fix csum_start when VLAN tags are present

From: Herbert Xu <herbert@...dor.apana.org.au>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 3ce9b20f1971690b8b3b620e735ec99431573b39 upstream.

When VLAN is in use in macvtap_put_user, we end up setting
csum_start to the wrong place.  The result is that the whoever
ends up doing the checksum setting will corrupt the packet instead
of writing the checksum to the expected location, usually this
means writing the checksum with an offset of -4.

This patch fixes this by adjusting csum_start when VLAN tags are
detected.

Fixes: f09e2249c4f5 ("macvtap: restore vlan header on user read")
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Signed-off-by: David S. Miller <davem@...emloft.net>
---
 drivers/net/macvtap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 4abd98efdc34..89d21fc47a16 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -625,6 +625,8 @@ static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
 		vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 		vnet_hdr->csum_start = skb_checksum_start_offset(skb);
+		if (vlan_tx_tag_present(skb))
+			vnet_hdr->csum_start += VLAN_HLEN;
 		vnet_hdr->csum_offset = skb->csum_offset;
 	} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 		vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
-- 
2.1.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/