[PATCH] net/ipv4: swap flow ports when validating source

[PATCH] net/ipv4: swap flow ports when validating source

[Wang Shanker]

When doing source address validation, the flowi4 struct used for
fib_lookup should be in the reverse direction to the given skb.
fl4_dport and fl4_sport returned by fib4_rules_early_flow_dissect
should thus be swapped.

Fixes: 5a847a6 ("net/ipv4: Initialize proto and ports in flow struct")
Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
---
 net/ipv4/fib_frontend.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 84bb707bd88d..647bceab56c2 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -371,6 +371,8 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 		fl4.flowi4_proto = 0;
 		fl4.fl4_sport = 0;
 		fl4.fl4_dport = 0;
+	} else {
+		swap(fl4.fl4_sport, fl4.fl4_dport);
 	}
 
 	if (fib_lookup(net, &fl4, &res, 0))
-- 
2.20.1

Re: [PATCH] net/ipv4: swap flow ports when validating source

[David Ahern]

On 6/21/21 9:17 AM, Wang Shanker wrote:
> When doing source address validation, the flowi4 struct used for
> fib_lookup should be in the reverse direction to the given skb.
> fl4_dport and fl4_sport returned by fib4_rules_early_flow_dissect
> should thus be swapped.
> 
> Fixes: 5a847a6 ("net/ipv4: Initialize proto and ports in flow struct")

I believe the hash should be 12 chars: 5a847a6e1477

> Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
> ---
>  net/ipv4/fib_frontend.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
> index 84bb707bd88d..647bceab56c2 100644
> --- a/net/ipv4/fib_frontend.c
> +++ b/net/ipv4/fib_frontend.c
> @@ -371,6 +371,8 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
>  		fl4.flowi4_proto = 0;
>  		fl4.fl4_sport = 0;
>  		fl4.fl4_dport = 0;
> +	} else {
> +		swap(fl4.fl4_sport, fl4.fl4_dport);
>  	}
>  
>  	if (fib_lookup(net, &fl4, &res, 0))
> 

Reviewed-by: David Ahern <dsahern@kernel.org>

Re: [PATCH] net/ipv4: swap flow ports when validating source

[Miao Wang]

> 2021年06月22日 09:23，David Ahern <dsahern@gmail.com> 写道：
> 
> On 6/21/21 9:17 AM, Wang Shanker wrote:
>> When doing source address validation, the flowi4 struct used for
>> fib_lookup should be in the reverse direction to the given skb.
>> fl4_dport and fl4_sport returned by fib4_rules_early_flow_dissect
>> should thus be swapped.
>> 
>> Fixes: 5a847a6 ("net/ipv4: Initialize proto and ports in flow struct")
> 
> I believe the hash should be 12 chars: 5a847a6e1477
> 
>> Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
>> ---
>> net/ipv4/fib_frontend.c | 2 ++
>> 1 file changed, 2 insertions(+)
>> 
>> diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
>> index 84bb707bd88d..647bceab56c2 100644
>> --- a/net/ipv4/fib_frontend.c
>> +++ b/net/ipv4/fib_frontend.c
>> @@ -371,6 +371,8 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
>> 		fl4.flowi4_proto = 0;
>> 		fl4.fl4_sport = 0;
>> 		fl4.fl4_dport = 0;
>> +	} else {
>> +		swap(fl4.fl4_sport, fl4.fl4_dport);
>> 	}
>> 
>> 	if (fib_lookup(net, &fl4, &res, 0))
>> 
> 
> Reviewed-by: David Ahern <dsahern@kernel.org>

Thanks for your suggestion. I wonder if I also CC this to 
stable?

Re: [PATCH] net/ipv4: swap flow ports when validating source

[David Ahern]

On 6/21/21 8:39 PM, Miao Wang wrote:
> Thanks for your suggestion. I wonder if I also CC this to 
> stable?

nope. Fixes tag will take care of that.

[PATCH v2] net/ipv4: swap flow ports when validating source

[Miao Wang]

When doing source address validation, the flowi4 struct used for
fib_lookup should be in the reverse direction to the given skb.
fl4_dport and fl4_sport returned by fib4_rules_early_flow_dissect
should thus be swapped.

Fixes: 5a847a6e1477 ("net/ipv4: Initialize proto and ports in flow struct")
Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
---
 net/ipv4/fib_frontend.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 84bb707bd88d..647bceab56c2 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -371,6 +371,8 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 		fl4.flowi4_proto = 0;
 		fl4.fl4_sport = 0;
 		fl4.fl4_dport = 0;
+	} else {
+		swap(fl4.fl4_sport, fl4.fl4_dport);
 	}
 
 	if (fib_lookup(net, &fl4, &res, 0))
-- 
2.20.1

Re: [PATCH v2] net/ipv4: swap flow ports when validating source

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Tue, 22 Jun 2021 12:24:50 +0800 you wrote:
> When doing source address validation, the flowi4 struct used for
> fib_lookup should be in the reverse direction to the given skb.
> fl4_dport and fl4_sport returned by fib4_rules_early_flow_dissect
> should thus be swapped.
> 
> Fixes: 5a847a6e1477 ("net/ipv4: Initialize proto and ports in flow struct")
> Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
> Reviewed-by: David Ahern <dsahern@kernel.org>
> 
> [...]

Here is the summary with links:
  - [v2] net/ipv4: swap flow ports when validating source
    https://git.kernel.org/netdev/net/c/c69f114d0989

You are awesome, thank you!
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