[PATCH v2] netfilter: conntrack: validate cta_ip via parsing

[PATCH v2] netfilter: conntrack: validate cta_ip via parsing

[Lin Ma]

In current ctnetlink_parse_tuple_ip() function, nested parsing and
validation is splitting as two parts,  which could be cleanup to a
simplified form. As the nla_parse_nested_deprecated function
supports validation in the fly. These two finially reach same place
__nla_validate_parse with same validate flag.

nla_parse_nested_deprecated
  __nla_parse(.., NL_VALIDATE_LIBERAL, ..)
    __nla_validate_parse

nla_validate_nested_deprecated
  __nla_validate_nested(.., NL_VALIDATE_LIBERAL, ..)
    __nla_validate
      __nla_validate_parse

This commit removes the call to nla_validate_nested_deprecated and pass
cta_ip_nla_policy when do parsing.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
V1 -> V2: remove Fixes tag as this does not fix anything,
          and adjust the commit message

 net/netfilter/nf_conntrack_netlink.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 69c8c8c7e9b8..334db22199c1 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1321,15 +1321,11 @@ static int ctnetlink_parse_tuple_ip(struct nlattr *attr,
 	struct nlattr *tb[CTA_IP_MAX+1];
 	int ret = 0;
 
-	ret = nla_parse_nested_deprecated(tb, CTA_IP_MAX, attr, NULL, NULL);
+	ret = nla_parse_nested_deprecated(tb, CTA_IP_MAX, attr,
+					  cta_ip_nla_policy, NULL);
 	if (ret < 0)
 		return ret;
 
-	ret = nla_validate_nested_deprecated(attr, CTA_IP_MAX,
-					     cta_ip_nla_policy, NULL);
-	if (ret)
-		return ret;
-
 	switch (tuple->src.l3num) {
 	case NFPROTO_IPV4:
 		ret = ipv4_nlattr_to_tuple(tb, tuple, flags);
-- 
2.17.1

Re: [PATCH v2] netfilter: conntrack: validate cta_ip via parsing

[Simon Horman]

On Wed, Jul 12, 2023 at 09:32:36PM +0800, Lin Ma wrote:
> In current ctnetlink_parse_tuple_ip() function, nested parsing and
> validation is splitting as two parts,  which could be cleanup to a
> simplified form. As the nla_parse_nested_deprecated function
> supports validation in the fly. These two finially reach same place
> __nla_validate_parse with same validate flag.
> 
> nla_parse_nested_deprecated
>   __nla_parse(.., NL_VALIDATE_LIBERAL, ..)
>     __nla_validate_parse
> 
> nla_validate_nested_deprecated
>   __nla_validate_nested(.., NL_VALIDATE_LIBERAL, ..)
>     __nla_validate
>       __nla_validate_parse
> 
> This commit removes the call to nla_validate_nested_deprecated and pass
> cta_ip_nla_policy when do parsing.
> 
> Signed-off-by: Lin Ma <linma@zju.edu.cn>

Reviewed-by: Simon Horman <simon.horman@corigine.com>