From: Patrick McHardy Date: Sun, 13 Apr 2008 01:35:41 +0000 (-0700) Subject: [DCCP]: Fix skb->cb conflicts with IP X-Git-Tag: v2.6.25~33^2~18 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=028b027524b162eef90839a92ba4b8bddf23e06c;p=linux-2.6 [DCCP]: Fix skb->cb conflicts with IP dev_queue_xmit() and the other IP output functions expect to get a skb with clear or properly initialized skb->cb. Unlike TCP and UDP, the dccp_skb_cb doesn't contain a struct inet_skb_parm at the beginning, so the DCCP-specific data is interpreted by the IP output functions. This can cause false negatives for the conditional POST_ROUTING hook invocation, making the packet bypass the hook. Add a inet_skb_parm/inet6_skb_parm union to the beginning of dccp_skb_cb to avoid clashes. Also add a BUILD_BUG_ON to make sure it fits in the cb. [ Combined with patch from Gerrit Renker to remove two now unnecessary memsets of IPCB(skb)->opt ] Signed-off-by: Patrick McHardy Acked-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index 287a62bc2e..ba2ef94a23 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -325,6 +325,12 @@ static inline int dccp_bad_service_code(const struct sock *sk, * This is used for transmission as well as for reception. */ struct dccp_skb_cb { + union { + struct inet_skb_parm h4; +#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) + struct inet6_skb_parm h6; +#endif + } header; __u8 dccpd_type:4; __u8 dccpd_ccval:4; __u8 dccpd_reset_code, diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 474075adbd..b337044155 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -489,7 +489,6 @@ static int dccp_v4_send_response(struct sock *sk, struct request_sock *req, dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr, ireq->rmt_addr); - memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, ireq->rmt_addr, ireq->opt); diff --git a/net/dccp/output.c b/net/dccp/output.c index 3b763db3d8..3d7d628d87 100644 --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -126,7 +126,6 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) DCCP_INC_STATS(DCCP_MIB_OUTSEGS); - memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); err = icsk->icsk_af_ops->queue_xmit(skb, 0); return net_xmit_eval(err); } diff --git a/net/dccp/proto.c b/net/dccp/proto.c index e3f5d37b84..c91d3c1fd3 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -1057,6 +1057,9 @@ static int __init dccp_init(void) int ehash_order, bhash_order, i; int rc = -ENOBUFS; + BUILD_BUG_ON(sizeof(struct dccp_skb_cb) > + FIELD_SIZEOF(struct sk_buff, cb)); + dccp_hashinfo.bind_bucket_cachep = kmem_cache_create("dccp_bind_bucket", sizeof(struct inet_bind_bucket), 0,