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Date: Sun, 15 Nov 2015 01:45:45 +0000 From: Ben Hutchings <ben@...adent.org.uk> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org CC: akpm@...ux-foundation.org, "David S. Miller" <davem@...emloft.net>, "Andrew Vagin" <avagin@...n.com>, "Pravin B Shelar" <pshelar@...ira.com> Subject: [PATCH 3.2 53/60] skbuff: Fix skb checksum partial check. 3.2.73-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Pravin B Shelar <pshelar@...ira.com> [ 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@...n.com> Signed-off-by: Pravin B Shelar <pshelar@...ira.com> Signed-off-by: David S. Miller <davem@...emloft.net> Signed-off-by: Ben Hutchings <ben@...adent.org.uk> --- include/linux/skbuff.h | 2 +- net/core/skbuff.c | 9 +++++---- 2 files changed, 6 insertions(+), 5 deletions(-) --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2046,7 +2046,7 @@ 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; } --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2579,11 +2579,12 @@ 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); -- 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/
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