diff options
| -rw-r--r-- | net/core/dev.c | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 39aba4862f2..38b03da5c1c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1362,22 +1362,21 @@ int skb_checksum_help(struct sk_buff *skb) goto out_set_summed; } - if (skb_cloned(skb)) { + offset = skb->csum_start - skb_headroom(skb); + BUG_ON(offset >= skb_headlen(skb)); + csum = skb_checksum(skb, offset, skb->len - offset, 0); + + offset += skb->csum_offset; + BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb)); + + if (skb_cloned(skb) && + !skb_clone_writable(skb, offset + sizeof(__sum16))) { ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); if (ret) goto out; } - offset = skb->csum_start - skb_headroom(skb); - BUG_ON(offset > (int)skb->len); - csum = skb_checksum(skb, offset, skb->len-offset, 0); - - offset = skb_headlen(skb) - offset; - BUG_ON(offset <= 0); - BUG_ON(skb->csum_offset + 2 > offset); - - *(__sum16 *)(skb->head + skb->csum_start + skb->csum_offset) = - csum_fold(csum); + *(__sum16 *)(skb->data + offset) = csum_fold(csum); out_set_summed: skb->ip_summed = CHECKSUM_NONE; out: |