| From | Jiri Slaby <> | Subject | [PATCH 3.12 086/123] skbuff: Fix skb checksum partial check. | Date | Wed, 28 Oct 2015 14:53:17 +0100 |
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From: Pravin B Shelar <pshelar@nicira.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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[ 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.
Fixes: 6ae459bda ("skbuff: Fix skb checksum flag on skb pull") Reported-by: Andrew Vagin <avagin@odin.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- include/linux/skbuff.h | 2 +- net/core/skbuff.c | 9 +++++---- 2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 80fad984cd8e..16e753a9922a 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2265,7 +2265,7 @@ static inline void skb_postpull_rcsum(struct sk_buff *skb, 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; } diff --git a/net/core/skbuff.c b/net/core/skbuff.c index b01dd5f421da..de76393a9916 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2726,11 +2726,12 @@ 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); -- 2.6.2
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