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| author | Eric Dumazet <edumazet@google.com> | 2016-10-29 21:02:36 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-10-31 22:29:11 +0300 |
| commit | 4f2e4ad56a65f3b7d64c258e373cb71e8d2499f4 (patch) | |
| tree | bda55b33236870d871bc3402abc8b14f4f262f56 | |
| parent | e551c32d57c88923f99f8f010e89ca7ed0735e83 (diff) | |
| download | linux-4f2e4ad56a65f3b7d64c258e373cb71e8d2499f4.tar.xz | |
net: mangle zero checksum in skb_checksum_help()
Sending zero checksum is ok for TCP, but not for UDP.
UDPv6 receiver should by default drop a frame with a 0 checksum,
and UDPv4 would not verify the checksum and might accept a corrupted
packet.
Simply replace such checksum by 0xffff, regardless of transport.
This error was caught on SIT tunnels, but seems generic.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/dev.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 820bac239738..eaad4c28069f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2484,7 +2484,7 @@ int skb_checksum_help(struct sk_buff *skb) goto out; } - *(__sum16 *)(skb->data + offset) = csum_fold(csum); + *(__sum16 *)(skb->data + offset) = csum_fold(csum) ?: CSUM_MANGLED_0; out_set_summed: skb->ip_summed = CHECKSUM_NONE; out: |