diff options
| author | Willem de Bruijn <willemb@google.com> | 2016-07-12 18:18:57 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-10 10:25:51 +0200 |
| commit | 792d5414d01409a229b3b2a5031b6167a8656bd6 (patch) | |
| tree | 9faa28d0ca751eda8f9a3d9dfe7453db1bb2c7e9 /net/dccp | |
| parent | 6c687c0c284e65a350bd1e50072b13ff8e322b9c (diff) | |
dccp: limit sk_filter trim to payload
commit 4f0c40d94461cfd23893a17335b2ab78ecb333c8 upstream.
Dccp verifies packet integrity, including length, at initial rcv in
dccp_invalid_packet, later pulls headers in dccp_enqueue_skb.
A call to sk_filter in-between can cause __skb_pull to wrap skb->len.
skb_copy_datagram_msg interprets this as a negative value, so
(correctly) fails with EFAULT. The negative length is reported in
ioctl SIOCINQ or possibly in a DCCP_WARN in dccp_close.
Introduce an sk_receive_skb variant that caps how small a filter
program can trim packets, and call this in dccp with the header
length. Excessively trimmed packets are now processed normally and
queued for reception as 0B payloads.
Fixes: 7c657876b63c ("[DCCP]: Initial implementation")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/dccp')
| -rw-r--r-- | net/dccp/ipv4.c | 2 | ||||
| -rw-r--r-- | net/dccp/ipv6.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index ef4c44d46293..3f51280374f0 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -868,7 +868,7 @@ lookup: goto discard_and_relse; nf_reset(skb); - return sk_receive_skb(sk, skb, 1); + return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4); no_dccp_socket: if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index d2caa4d69159..10eabd1a60aa 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -741,7 +741,7 @@ lookup: if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse; - return sk_receive_skb(sk, skb, 1) ? -1 : 0; + return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4) ? -1 : 0; no_dccp_socket: if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) |