From c182a3676e5a716a07be2c9cd269a25e599d880b Mon Sep 17 00:00:00 2001 From: Pravin B Shelar Date: Thu, 10 Dec 2015 14:42:43 -0800 Subject: [PATCH] datapath: Backport: skbuff: Fix skb checksum partial check. This bug fix is not required for OVS use cases. But is it nice to keep function consistent with upstream implementation. Upstream commit: 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 Signed-off-by: Pravin B Shelar Signed-off-by: David S. Miller Upstream: 31b33dfb0a1 ("skbuff: Fix skb checksum partial check"); Signed-off-by: Pravin B Shelar Acked-by: Jesse Gross --- datapath/linux/compat/include/linux/skbuff.h | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/datapath/linux/compat/include/linux/skbuff.h b/datapath/linux/compat/include/linux/skbuff.h index 0edcbfdd2..ab54a83fa 100644 --- a/datapath/linux/compat/include/linux/skbuff.h +++ b/datapath/linux/compat/include/linux/skbuff.h @@ -371,18 +371,19 @@ 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; } #define skb_pull_rcsum rpl_skb_pull_rcsum static inline 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; } #endif -- 2.20.1