[2/3] gso: Handle new frag_list of frags GRO packets

Herbert Xu
2013-11-07T07:06:54Z

Recently GRO started generating packets with frag_lists of frags.
This was not handled by GSO, thus leading to a crash.

Thankfully these packets are of a regular form and are easy to
handle. This patch handles them by calling skb_segment for each
frag_list entry. The depth of recursion is limited to just one.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 88b7dc6..bcc3f1c 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2816,8 +2816,6 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
hsize = len;

if (!hsize && i >= nfrags) {
- BUG_ON(fskb->len != len);
-
pos += len;
nskb = skb_clone(fskb, GFP_ATOMIC);
fskb = fskb->next;
@@ -2855,8 +2853,40 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
nskb->data - tnl_hlen,
doffset + tnl_hlen);

- if (fskb != skb_shinfo(skb)->frag_list)
- goto perform_csum_check;
+ if (fskb != skb_shinfo(skb)->frag_list) {
+ struct sk_buff *nsegs;
+
+ if (nskb->len == len + doffset)
+ goto perform_csum_check;
+
+ SKB_FRAG_ASSERT(nskb);
+
+ __skb_pull(nskb, doffset);
+ skb_shinfo(nskb)->gso_size = mss;
+ nsegs = skb_segment(nskb, features);
+
+ err = PTR_ERR(nsegs);
+ if (IS_ERR(nsegs)) {
+ kfree(nskb);
+ goto err;
+ }
+ err = -ENOMEM;
+
+ if (segs)
+ tail->next = nsegs;
+ else
+ segs = nsegs;
+
+ tail = nsegs;
+ while (tail->next)
+ tail = tail->next;
+
+ BUG_ON(fskb && tail->len != len + doffset);
+
+ len = nskb->len;
+ kfree(nskb);
+ continue;
+ }

if (!sg) {
nskb->ip_summed = CHECKSUM_NONE;
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt