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authorPatrick McHardy <kaber@trash.net>2008-04-12 18:35:41 -0700
committerDavid S. Miller <davem@davemloft.net>2008-04-12 18:35:41 -0700
commit028b027524b162eef90839a92ba4b8bddf23e06c (patch)
tree5c128717f73ff6fb93c361cfae6961267ed52082
parentae1b6a31b1f9ef2c7ba5ef89799f210a9ba6937c (diff)
[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 <kaber@trash.net> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/dccp/dccp.h6
-rw-r--r--net/dccp/ipv4.c1
-rw-r--r--net/dccp/output.c1
-rw-r--r--net/dccp/proto.c3
4 files changed, 9 insertions, 2 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 287a62bc2e0..ba2ef94a230 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 474075adbde..b3370441555 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 3b763db3d86..3d7d628d870 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 e3f5d37b84b..c91d3c1fd30 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,