Patch "skbuff: Fix skb checksum partial check." has been added to the 3.14-stable tree

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

skbuff: Fix skb checksum partial check.

to the 3.14-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:
skbuff-fix-skb-checksum-partial-check.patch
and it can be found in the queue-3.14 subdirectory.

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

From: Pravin B Shelar <[email protected]>
Date: Mon, 28 Sep 2015 17:24:25 -0700
Subject: skbuff: Fix skb checksum partial check.

From: Pravin B Shelar <[email protected]>

[ Upstream commit 31b33dfb0a144469dd805514c9e63f4993729a48 ]

Earlier patch 6ae459bda tried to detect void ckecksum partial skb by comparing pull length to checksum offset. But it does not work for all cases since checksum-offset depends on updates to skb->data.

Following patch fixes it by validating checksum start offset after skb-data pointer is updated. Negative value of checksum offset start means there is no need to checksum.

---
 include/linux/skbuff.h |    2 +-
 net/core/skbuff.c      |    9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

@@ -2348,7 +2348,7 @@ static inline void skb_postpull_rcsum(st
 	if (skb->ip_summed == CHECKSUM_COMPLETE)
 		skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
 	else if (skb->ip_summed == CHECKSUM_PARTIAL &&
-		 skb_checksum_start_offset(skb) <= len)
+		 skb_checksum_start_offset(skb) < 0)
 		skb->ip_summed = CHECKSUM_NONE;
 }
 

@@ -2862,11 +2862,12 @@ EXPORT_SYMBOL(skb_append_datato_frags);
  */
 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
 {
+	unsigned char *data = skb->data;
+
 	BUG_ON(len > skb->len);
-	skb->len -= len;
-	BUG_ON(skb->len < skb->data_len);
-	skb_postpull_rcsum(skb, skb->data, len);
-	return skb->data += len;
+	__skb_pull(skb, len);
+	skb_postpull_rcsum(skb, data, len);
+	return skb->data;
 }
 EXPORT_SYMBOL_GPL(skb_pull_rcsum);
 

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

queue-3.14/skbuff-fix-skb-checksum-flag-on-skb-pull.patch queue-3.14/skbuff-fix-skb-checksum-partial-check.patch