[PATCH] netfilter: ipset: Fix maximal range check in hash_ipportnet4_uadt()

[PATCH] netfilter: ipset: Fix maximal range check in hash_ipportnet4_uadt()

[Nathan Chancellor]

Clang warns:

net/netfilter/ipset/ip_set_hash_ipportnet.c:249:29: warning: variable
'port_to' is uninitialized when used here [-Wuninitialized]
        if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
                                   ^~~~~~~
net/netfilter/ipset/ip_set_hash_ipportnet.c:167:45: note: initialize the
variable 'port_to' to silence this warning
        u32 ip = 0, ip_to = 0, p = 0, port, port_to;
                                                   ^
                                                    = 0
net/netfilter/ipset/ip_set_hash_ipportnet.c:249:39: warning: variable
'port' is uninitialized when used here [-Wuninitialized]
        if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
                                             ^~~~
net/netfilter/ipset/ip_set_hash_ipportnet.c:167:36: note: initialize the
variable 'port' to silence this warning
        u32 ip = 0, ip_to = 0, p = 0, port, port_to;
                                          ^
                                           = 0
2 warnings generated.

The range check was added before port and port_to are initialized.
Shuffle the check after the initialization so that the check works
properly.

Fixes: 7fb6c63025ff ("netfilter: ipset: Limit the maximal range of consecutive elements to add/delete")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 net/netfilter/ipset/ip_set_hash_ipportnet.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_ipportnet.c b/net/netfilter/ipset/ip_set_hash_ipportnet.c
index b293aa1ff258..7df94f437f60 100644
--- a/net/netfilter/ipset/ip_set_hash_ipportnet.c
+++ b/net/netfilter/ipset/ip_set_hash_ipportnet.c
@@ -246,9 +246,6 @@ hash_ipportnet4_uadt(struct ip_set *set, struct nlattr *tb[],
 		ip_set_mask_from_to(ip, ip_to, cidr);
 	}
 
-	if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
-		return -ERANGE;
-
 	port_to = port = ntohs(e.port);
 	if (tb[IPSET_ATTR_PORT_TO]) {
 		port_to = ip_set_get_h16(tb[IPSET_ATTR_PORT_TO]);
@@ -256,6 +253,9 @@ hash_ipportnet4_uadt(struct ip_set *set, struct nlattr *tb[],
 			swap(port, port_to);
 	}
 
+	if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
+		return -ERANGE;
+
 	ip2_to = ip2_from;
 	if (tb[IPSET_ATTR_IP2_TO]) {
 		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP2_TO], &ip2_to);

base-commit: 4d3fc8ead710a06c98d36f382777c6a843a83b7c
-- 
2.33.0.rc0

Re: [PATCH] netfilter: ipset: Fix maximal range check in hash_ipportnet4_uadt()

[Jozsef Kadlecsik]

Hi,

On Tue, 3 Aug 2021, Nathan Chancellor wrote:

> Clang warns:
> 
> net/netfilter/ipset/ip_set_hash_ipportnet.c:249:29: warning: variable
> 'port_to' is uninitialized when used here [-Wuninitialized]
>         if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
>                                    ^~~~~~~
> net/netfilter/ipset/ip_set_hash_ipportnet.c:167:45: note: initialize the
> variable 'port_to' to silence this warning
>         u32 ip = 0, ip_to = 0, p = 0, port, port_to;
>                                                    ^
>                                                     = 0
> net/netfilter/ipset/ip_set_hash_ipportnet.c:249:39: warning: variable
> 'port' is uninitialized when used here [-Wuninitialized]
>         if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
>                                              ^~~~
> net/netfilter/ipset/ip_set_hash_ipportnet.c:167:36: note: initialize the
> variable 'port' to silence this warning
>         u32 ip = 0, ip_to = 0, p = 0, port, port_to;
>                                           ^
>                                            = 0
> 2 warnings generated.
> 
> The range check was added before port and port_to are initialized.
> Shuffle the check after the initialization so that the check works
> properly.
> 
> Fixes: 7fb6c63025ff ("netfilter: ipset: Limit the maximal range of consecutive elements to add/delete")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Yes, good catch!

Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>

Best regards,
Jozsef
> ---
>  net/netfilter/ipset/ip_set_hash_ipportnet.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/netfilter/ipset/ip_set_hash_ipportnet.c b/net/netfilter/ipset/ip_set_hash_ipportnet.c
> index b293aa1ff258..7df94f437f60 100644
> --- a/net/netfilter/ipset/ip_set_hash_ipportnet.c
> +++ b/net/netfilter/ipset/ip_set_hash_ipportnet.c
> @@ -246,9 +246,6 @@ hash_ipportnet4_uadt(struct ip_set *set, struct nlattr *tb[],
>  		ip_set_mask_from_to(ip, ip_to, cidr);
>  	}
>  
> -	if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
> -		return -ERANGE;
> -
>  	port_to = port = ntohs(e.port);
>  	if (tb[IPSET_ATTR_PORT_TO]) {
>  		port_to = ip_set_get_h16(tb[IPSET_ATTR_PORT_TO]);
> @@ -256,6 +253,9 @@ hash_ipportnet4_uadt(struct ip_set *set, struct nlattr *tb[],
>  			swap(port, port_to);
>  	}
>  
> +	if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
> +		return -ERANGE;
> +
>  	ip2_to = ip2_from;
>  	if (tb[IPSET_ATTR_IP2_TO]) {
>  		ret = ip_set_get_hostipaddr4(tb[IPSET_ATTR_IP2_TO], &ip2_to);
> 
> base-commit: 4d3fc8ead710a06c98d36f382777c6a843a83b7c
> -- 
> 2.33.0.rc0
> 
> 

-
E-mail  : kadlec@blackhole.kfki.hu, kadlecsik.jozsef@wigner.hu
PGP key : https://wigner.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics
          H-1525 Budapest 114, POB. 49, Hungary

Re: [PATCH] netfilter: ipset: Fix maximal range check in hash_ipportnet4_uadt()

[Pablo Neira Ayuso]

On Tue, Aug 03, 2021 at 12:18:13PM -0700, Nathan Chancellor wrote:
> Clang warns:
> 
> net/netfilter/ipset/ip_set_hash_ipportnet.c:249:29: warning: variable
> 'port_to' is uninitialized when used here [-Wuninitialized]
>         if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
>                                    ^~~~~~~
> net/netfilter/ipset/ip_set_hash_ipportnet.c:167:45: note: initialize the
> variable 'port_to' to silence this warning
>         u32 ip = 0, ip_to = 0, p = 0, port, port_to;
>                                                    ^
>                                                     = 0
> net/netfilter/ipset/ip_set_hash_ipportnet.c:249:39: warning: variable
> 'port' is uninitialized when used here [-Wuninitialized]
>         if (((u64)ip_to - ip + 1)*(port_to - port + 1) > IPSET_MAX_RANGE)
>                                              ^~~~
> net/netfilter/ipset/ip_set_hash_ipportnet.c:167:36: note: initialize the
> variable 'port' to silence this warning
>         u32 ip = 0, ip_to = 0, p = 0, port, port_to;
>                                           ^
>                                            = 0
> 2 warnings generated.
> 
> The range check was added before port and port_to are initialized.
> Shuffle the check after the initialization so that the check works
> properly.

For the record: I have squashed this fix into the original patch in
nf.git to make it easier to pass it on to -stable.

Thanks.