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udp: fix skb_copy_and_csum_datagram with odd segment sizes

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commit 52cbd23a119c6ebf40a527e53f3402d2ea38eccb upstream.

When iteratively computing a checksum with csum_block_add, track the
offset "pos" to correctly rotate in csum_block_add when offset is odd.

The open coded implementation of skb_copy_and_csum_datagram did this.
With the switch to __skb_datagram_iter calling csum_and_copy_to_iter,
pos was reinitialized to 0 on each call.

Bring back the pos by passing it along with the csum to the callback.

Changes v1->v2
  - pass csum value, instead of csump pointer (Alexander Duyck)

Link: https://lore.kernel.org/netdev/20210128152353.GB27281@optiplex/
Fixes: 950fcaecd5 ("datagram: consolidate datagram copy to iter helpers")
Reported-by: Oliver Graute <oliver.graute@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20210203192952.1849843-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Willem de Bruijn
2021-02-03 14:29:52 -05:00
committed by Greg Kroah-Hartman
parent 24f5544f76
commit 46a831d1cc
3 changed files with 31 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
net/core/datagram.c
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@@ -721,8 +721,16 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
struct iov_iter *to, int len,
__wsum *csump)
{
return __skb_datagram_iter(skb, offset, to, len, true,
csum_and_copy_to_iter, csump);
struct csum_state csdata = { .csum = *csump };
int ret;
ret = __skb_datagram_iter(skb, offset, to, len, true,
csum_and_copy_to_iter, &csdata);
if (ret)
return ret;
*csump = csdata.csum;
return 0;
}
/**