[PATCH net] net/ipv4: Initialize proto and ports in flow struct

[PATCH net] net/ipv4: Initialize proto and ports in flow struct

[David Ahern]

Updating the FIB tracepoint for the recent change to allow rules using
the protocol and ports exposed a few places where the entries in the flow
struct are not initialized.

For __fib_validate_source add the call to fib4_rules_early_flow_dissect
since it is invoked for the input path. For netfilter, add the memset on
the flow struct to avoid future problems like this.

Fixes: bfff4862653b ("net: fib_rules: support for match on ip_proto, sport and dport")
Signed-off-by: David Ahern <dsahern@gmail.com>
---
 net/ipv4/fib_frontend.c           | 10 +++++++---
 net/ipv4/netfilter/ipt_rpfilter.c |  2 +-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index f05afaf3235c..58696b829065 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -326,10 +326,11 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 				 u8 tos, int oif, struct net_device *dev,
 				 int rpf, struct in_device *idev, u32 *itag)
 {
+	struct net *net = dev_net(dev);
+	struct flow_keys flkeys;
 	int ret, no_addr;
 	struct fib_result res;
 	struct flowi4 fl4;
-	struct net *net = dev_net(dev);
 	bool dev_match;
 
 	fl4.flowi4_oif = 0;
@@ -347,8 +348,11 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 	no_addr = idev->ifa_list == NULL;
 
 	fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
-
-	trace_fib_validate_source(dev, &fl4);
+	if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
+		fl4.flowi4_proto = 0;
+		fl4.fl4_sport = 0;
+		fl4.fl4_dport = 0;
+	}
 
 	if (fib_lookup(net, &fl4, &res, 0))
 		goto last_resort;
diff --git a/net/ipv4/netfilter/ipt_rpfilter.c b/net/ipv4/netfilter/ipt_rpfilter.c
index fd01f13c896a..12843c9ef142 100644
--- a/net/ipv4/netfilter/ipt_rpfilter.c
+++ b/net/ipv4/netfilter/ipt_rpfilter.c
@@ -89,10 +89,10 @@ static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par)
 			return true ^ invert;
 	}
 
+	memset(&flow, 0, sizeof(flow));
 	flow.flowi4_iif = LOOPBACK_IFINDEX;
 	flow.daddr = iph->saddr;
 	flow.saddr = rpfilter_get_saddr(iph->daddr);
-	flow.flowi4_oif = 0;
 	flow.flowi4_mark = info->flags & XT_RPFILTER_VALID_MARK ? skb->mark : 0;
 	flow.flowi4_tos = RT_TOS(iph->tos);
 	flow.flowi4_scope = RT_SCOPE_UNIVERSE;
-- 
2.11.0

Re: [PATCH net] net/ipv4: Initialize proto and ports in flow struct

[David Ahern]

On 5/16/18 12:18 PM, David Ahern wrote:

> @@ -347,8 +348,11 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
>  	no_addr = idev->ifa_list == NULL;
>  
>  	fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
> -
> -	trace_fib_validate_source(dev, &fl4);

Looks like I sent the net-next version; did not mean to remove that
tracepoint in net. Will send v2


> +	if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
> +		fl4.flowi4_proto = 0;
> +		fl4.fl4_sport = 0;
> +		fl4.fl4_dport = 0;
> +	}
>  
>  	if (fib_lookup(net, &fl4, &res, 0))
>  		goto last_resort;