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Patch "udp: use sk_filter_trim_cap for udp{,6}_queue_rcv_skb" has been added to the 4.7-stable tree

PATCH [email protected] 1 participant 1 message Aug 12, 2016

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This is a note to let you know that I've just added the patch titled

udp: use sk_filter_trim_cap for udp{,6}_queue_rcv_skb

to the 4.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
udp-use-sk_filter_trim_cap-for-udp-6-_queue_rcv_skb.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Fri Aug 12 09:34:44 CEST 2016

From: Daniel Borkmann <[email protected]>
Date: Mon, 25 Jul 2016 18:06:12 +0200
Subject: udp: use sk_filter_trim_cap for udp{,6}_queue_rcv_skb

From: Daniel Borkmann <[email protected]>

[ Upstream commit ba66bbe5480a012108958a71cff88b23dce84956 ]

After a612769774a3 ("udp: prevent bugcheck if filter truncates packet too much"), there followed various other fixes for similar cases such as f4979fcea7fd ("rose: limit sk_filter trim to payload").

Latter introduced a new helper sk_filter_trim_cap(), where we can pass the trim limit directly to the socket filter handling. Make use of it here as well with sizeof(struct udphdr) as lower cap limit and drop the extra skb->len test in UDP's input path.

---
 net/ipv4/udp.c |    4 +---
 net/ipv6/udp.c |    4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)
net/ipv4/udp.c +1 -3
@@ -1581,9 +1581,7 @@ int udp_queue_rcv_skb(struct sock *sk, s
 	    udp_lib_checksum_complete(skb))
 			goto csum_error;
 
-	if (sk_filter(sk, skb))
-		goto drop;
-	if (unlikely(skb->len < sizeof(struct udphdr)))
+	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
 		goto drop;
 
 	udp_csum_pull_header(skb);
net/ipv6/udp.c +1 -3
@@ -618,9 +618,7 @@ int udpv6_queue_rcv_skb(struct sock *sk,
 	    udp_lib_checksum_complete(skb))
 		goto csum_error;
 
-	if (sk_filter(sk, skb))
-		goto drop;
-	if (unlikely(skb->len < sizeof(struct udphdr)))
+	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
 		goto drop;
 
 	udp_csum_pull_header(skb);

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/udp-use-sk_filter_trim_cap-for-udp-6-_queue_rcv_skb.patch