[PATCH net-next] net: ipv4: Fix NULL pointer dereference in route lookup

[PATCH net-next] net: ipv4: Fix NULL pointer dereference in route lookup

[Ido Schimmel]

When calculating the multipath hash for input routes the flow info is
not available and therefore should not be used.

Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Cc: wenxu <wenxu@ucloud.cn>
---
 net/ipv4/route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 7cf4c8305071..e3ac458b5d8b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1820,7 +1820,7 @@ static void ip_multipath_l3_keys(const struct sk_buff *skb,
 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
 		       const struct sk_buff *skb, struct flow_keys *flkeys)
 {
-	u32 multipath_hash = fl4->flowi4_multipath_hash;
+	u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
 	struct flow_keys hash_keys;
 	u32 mhash;
 
-- 
2.20.1

Re: [PATCH net-next] net: ipv4: Fix NULL pointer dereference in route lookup

[wenxu]

On 2019/3/1 下午9:38, Ido Schimmel wrote:
> When calculating the multipath hash for input routes the flow info is
> not available and therefore should not be used.
>
> Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
> Signed-off-by: Ido Schimmel <idosch@mellanox.com>
> Cc: wenxu <wenxu@ucloud.cn>
> ---
>  net/ipv4/route.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 7cf4c8305071..e3ac458b5d8b 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1820,7 +1820,7 @@ static void ip_multipath_l3_keys(const struct sk_buff *skb,
>  int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
>  		       const struct sk_buff *skb, struct flow_keys *flkeys)
>  {
> -	u32 multipath_hash = fl4->flowi4_multipath_hash;
> +	u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
>  	struct flow_keys hash_keys;
>  	u32 mhash;
>  

Acked-by: wenxu <wenxu@ucloud.cn>

Re: [PATCH net-next] net: ipv4: Fix NULL pointer dereference in route lookup

[Nikolay Aleksandrov]

On 01/03/2019 15:38, Ido Schimmel wrote:
> When calculating the multipath hash for input routes the flow info is
> not available and therefore should not be used.
> 
> Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
> Signed-off-by: Ido Schimmel <idosch@mellanox.com>
> Cc: wenxu <wenxu@ucloud.cn>
> ---
>  net/ipv4/route.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 7cf4c8305071..e3ac458b5d8b 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1820,7 +1820,7 @@ static void ip_multipath_l3_keys(const struct sk_buff *skb,
>  int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
>  		       const struct sk_buff *skb, struct flow_keys *flkeys)
>  {
> -	u32 multipath_hash = fl4->flowi4_multipath_hash;
> +	u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
>  	struct flow_keys hash_keys;
>  	u32 mhash;
>  
> 

indeed, missed it during review, thanks!
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

Re: [PATCH net-next] net: ipv4: Fix NULL pointer dereference in route lookup

[David Miller]

From: Ido Schimmel <idosch@mellanox.com>
Date: Fri, 1 Mar 2019 13:38:43 +0000

> When calculating the multipath hash for input routes the flow info is
> not available and therefore should not be used.
> 
> Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
> Signed-off-by: Ido Schimmel <idosch@mellanox.com>

Applied.