From: "Michael S. Tsirkin" <[email protected]> commit 1fd819ecb90cc9b822cd84d3056ddba315d3340f upstream.
skb_segment copies frags around, so we need to copy them carefully to avoid accessing user memory after reporting completion to userspace through a callback. skb_segment doesn't normally happen on datapath: TSO needs to be disabled - so disabling zero copy in this case does not look like a big deal. Signed-off-by: Michael S. Tsirkin <[email protected]> Acked-by: Herbert Xu <[email protected]> Signed-off-by: David S. Miller <[email protected]> [bwh: Backported to 3.2. As skb_segment() only supports page-frags *or* a frag list, there is no need for the additional frag_skb pointer or the preparatory renaming.] Signed-off-by: Ben Hutchings <[email protected]> --- For branches older than 3.6, commit a353e0ce0fd4 ('skbuff: add an api to orphan frags') is needed before this. This is untested and I would appreciate a review. Ben. --- --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2699,6 +2699,9 @@ struct sk_buff *skb_segment(struct sk_bu skb_put(nskb, hsize), hsize); while (pos < offset + len && i < nfrags) { + if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) + goto err; + *frag = skb_shinfo(skb)->frags[i]; __skb_frag_ref(frag); size = skb_frag_size(frag); -- Ben Hutchings I haven't lost my mind; it's backed up on tape somewhere.
signature.asc
Description: This is a digitally signed message part
