diff options
| author | Willem de Bruijn <willemb@google.com> | 2016-07-12 18:18:57 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-02-23 03:54:46 +0000 |
| commit | 49bbb1dc818f09bfb323ce5b36c47306ad9e94ac (patch) | |
| tree | 0c69fd11bb007c8b8e69489064a4470854be59e3 | |
| parent | d0fb92f2ca9b8c3ba10047b5e134cd7d1459cc1c (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: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | include/net/sock.h | 8 | ||||
| -rw-r--r-- | net/core/sock.c | 7 | ||||
| -rw-r--r-- | net/dccp/ipv4.c | 2 | ||||
| -rw-r--r-- | net/dccp/ipv6.c | 2 |
4 files changed, 13 insertions, 6 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index f957f7c4fa20..07ede95596bb 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1669,7 +1669,13 @@ static inline void sock_put(struct sock *sk) */ void sock_gen_put(struct sock *sk); -int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested); +int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested, + unsigned int trim_cap); +static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb, + const int nested) +{ + return __sk_receive_skb(sk, skb, nested, 1); +} static inline void sk_tx_queue_set(struct sock *sk, int tx_queue) { diff --git a/net/core/sock.c b/net/core/sock.c index 504a2a96ff79..3b301b9b9d5f 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -487,11 +487,12 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) } EXPORT_SYMBOL(sock_queue_rcv_skb); -int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested) +int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, + const int nested, unsigned int trim_cap) { int rc = NET_RX_SUCCESS; - if (sk_filter(sk, skb)) + if (sk_filter_trim_cap(sk, skb, trim_cap)) goto discard_and_relse; skb->dev = NULL; @@ -527,7 +528,7 @@ discard_and_relse: kfree_skb(skb); goto out; } -EXPORT_SYMBOL(sk_receive_skb); +EXPORT_SYMBOL(__sk_receive_skb); struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie) { diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 6ca645c4b48e..b371341d899d 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -890,7 +890,7 @@ static int dccp_v4_rcv(struct sk_buff *skb) 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 1149e345bba9..9f2dc1d15e43 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -804,7 +804,7 @@ static int dccp_v6_rcv(struct sk_buff *skb) 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)) |