net: Fix frag_list handling in skb_seq_read

[ Upstream commit 95e3b24cfb4ec0479d2c42f7a1780d68063a542a ]

The frag_list handling was broken in skb_seq_read:

1) We didn't add the stepped offset when looking at the head
are of fragments other than the first.

2) We didn't take the stepped offset away when setting the data
pointer in the head area.

3) The frag index wasn't reset.

This patch fixes both issues.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ca1ccdf1ef7612b87d16f53f803b2460de612360..798e2c6478aab2da347f32fd9fb11b8696a934c9 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2001,10 +2001,10 @@ unsigned int skb_seq_read(unsigned int consumed, const u8 **data,
                return 0;
 
 next_skb:
-       block_limit = skb_headlen(st->cur_skb);
+       block_limit = skb_headlen(st->cur_skb) + st->stepped_offset;
 
        if (abs_offset < block_limit) {
-               *data = st->cur_skb->data + abs_offset;
+               *data = st->cur_skb->data + (abs_offset - st->stepped_offset);
                return block_limit - abs_offset;
        }
 
@@ -2046,6 +2046,7 @@ next_skb:
        } else if (st->root_skb == st->cur_skb &&
                   skb_shinfo(st->root_skb)->frag_list) {
                st->cur_skb = skb_shinfo(st->root_skb)->frag_list;
+               st->frag_idx = 0;
                goto next_skb;
        }