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]> --- net/core/skbuff.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 64ee4e6..ae11f78 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2857,6 +2857,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, skb_frag_t *frag = skb_shinfo(head_skb)->frags; unsigned int mss = skb_shinfo(head_skb)->gso_size; unsigned int doffset = head_skb->data - skb_mac_header(head_skb); + struct sk_buff *frag_skb = head_skb; unsigned int offset = doffset; unsigned int tnl_hlen = skb_tnl_header_len(head_skb); unsigned int headroom; @@ -2901,6 +2902,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, i = 0; nfrags = skb_shinfo(list_skb)->nr_frags; frag = skb_shinfo(list_skb)->frags; + frag_skb = list_skb; pos += skb_headlen(list_skb); while (pos < offset + len) { @@ -2988,6 +2990,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, i = 0; nfrags = skb_shinfo(list_skb)->nr_frags; frag = skb_shinfo(list_skb)->frags; + frag_skb = list_skb; BUG_ON(!nfrags); @@ -3002,6 +3005,9 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, goto err; } + if (unlikely(skb_orphan_frags(frag_skb, GFP_ATOMIC))) + goto err; + *nskb_frag = *frag; __skb_frag_ref(nskb_frag); size = skb_frag_size(nskb_frag); -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
