ip: fix IP_CHECKSUM handling
The skbs processed by ip_cmsg_recv() are not guaranteed to
be linear e.g. when sending UDP packets over loopback with
MSGMORE.
Using csum_partial() on [potentially] the whole skb len
is dangerous; instead be on the safe side and use skb_checksum().
Thanks to syzkaller team to detect the issue and provide the
reproducer.
v1 -> v2:
- move the variable declaration in a tighter scope
Fixes: ad6f939ab1
("ip: Add offset parameter to ip_cmsg_recv")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
8dcd81a993
commit
ca4ef4574f
|
@ -116,10 +116,10 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
|
||||||
if (skb->ip_summed != CHECKSUM_COMPLETE)
|
if (skb->ip_summed != CHECKSUM_COMPLETE)
|
||||||
return;
|
return;
|
||||||
|
|
||||||
if (offset != 0)
|
if (offset != 0) {
|
||||||
csum = csum_sub(csum,
|
int tend_off = skb_transport_offset(skb) + tlen;
|
||||||
csum_partial(skb_transport_header(skb) + tlen,
|
csum = csum_sub(csum, skb_checksum(skb, tend_off, offset, 0));
|
||||||
offset, 0));
|
}
|
||||||
|
|
||||||
put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
|
put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
|
||||||
}
|
}
|
||||||
|
|
Loading…
Reference in New Issue