netdev - [net-next 5/5] net_sched: better precise estimation on packet length for untrusted packets

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

[an error occurred while processing this directive]

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

Message-Id: <1364278799-37285-6-git-send-email-jasowang@redhat.com>
Date:	Tue, 26 Mar 2013 14:19:59 +0800
From:	Jason Wang <jasowang@...hat.com>
To:	davem@...emloft.net, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	mst@...hat.com, Jason Wang <jasowang@...hat.com>,
	Eric Dumazet <edumazet@...gle.com>
Subject: [net-next 5/5] net_sched: better precise estimation on packet length for untrusted packets

gso_segs were reset to zero when kernel receive packets from untrusted
source. But we use this zero value to estimate precise packet len which is
wrong. So this patch tries to estimate the correct gso_segs value before using
it in qdisc_pkt_len_init().

Cc: Eric Dumazet <edumazet@...gle.com>
Signed-off-by: Jason Wang <jasowang@...hat.com>
---
 net/core/dev.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index de930b7..f5ad23b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2588,6 +2588,7 @@ static void qdisc_pkt_len_init(struct sk_buff *skb)
 	 */
 	if (shinfo->gso_size)  {
 		unsigned int hdr_len;
+		u16 gso_segs = shinfo->gso_segs;
 
 		/* mac layer + network layer */
 		hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
@@ -2597,7 +2598,12 @@ static void qdisc_pkt_len_init(struct sk_buff *skb)
 			hdr_len += tcp_hdrlen(skb);
 		else
 			hdr_len += sizeof(struct udphdr);
-		qdisc_skb_cb(skb)->pkt_len += (shinfo->gso_segs - 1) * hdr_len;
+
+		if (shinfo->gso_type & SKB_GSO_DODGY)
+			gso_segs = DIV_ROUND_UP(skb->len - hdr_len,
+						shinfo->gso_size);
+
+		qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len;
 	}
 }
 
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html