diff options
| author | Eric Dumazet <edumazet@google.com> | 2016-10-29 11:02:36 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-11-21 10:11:34 +0100 |
| commit | 0c7f764d2c6affb393e7031519a14935c5fa2586 (patch) | |
| tree | 58b4c922441c3bc5c30e5aa2b7a1f2712a48bce6 | |
| parent | ac22a3ba07964d39e8c2cf2abda7c610d861eefe (diff) | |
net: mangle zero checksum in skb_checksum_help()
[ Upstream commit 4f2e4ad56a65f3b7d64c258e373cb71e8d2499f4 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 44b3ba462ba1..9ce9d7284ea7 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: |