netdev - [PATCH 9/9] netfilter: nf_tables: skip flowtable hooknum and priority on device updates

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 29 May 2020 19:50:26 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org, kuba@...nel.org
Subject: [PATCH 9/9] netfilter: nf_tables: skip flowtable hooknum and priority on device updates

On device updates, the hooknum and priority attributes are not required.
This patch makes optional these two netlink attributes.

Moreover, bail out with EOPNOTSUPP if userspace tries to update the
hooknum and priority for existing flowtables.

While at this, turn EINVAL into EOPNOTSUPP in case the hooknum is not
ingress. EINVAL is reserved for missing netlink attribute / malformed
netlink messages.

Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nf_tables_api.c | 53 +++++++++++++++++++++++------------
 1 file changed, 35 insertions(+), 18 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 897ac5fbe079..073aa1051d43 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -6195,7 +6195,7 @@ static const struct nla_policy nft_flowtable_hook_policy[NFTA_FLOWTABLE_HOOK_MAX
 static int nft_flowtable_parse_hook(const struct nft_ctx *ctx,
 				    const struct nlattr *attr,
 				    struct nft_flowtable_hook *flowtable_hook,
-				    struct nf_flowtable *ft)
+				    struct nft_flowtable *flowtable, bool add)
 {
 	struct nlattr *tb[NFTA_FLOWTABLE_HOOK_MAX + 1];
 	struct nft_hook *hook;
@@ -6209,15 +6209,35 @@ static int nft_flowtable_parse_hook(const struct nft_ctx *ctx,
 	if (err < 0)
 		return err;
 
-	if (!tb[NFTA_FLOWTABLE_HOOK_NUM] ||
-	    !tb[NFTA_FLOWTABLE_HOOK_PRIORITY])
-		return -EINVAL;
+	if (add) {
+		if (!tb[NFTA_FLOWTABLE_HOOK_NUM] ||
+		    !tb[NFTA_FLOWTABLE_HOOK_PRIORITY])
+			return -EINVAL;
 
-	hooknum = ntohl(nla_get_be32(tb[NFTA_FLOWTABLE_HOOK_NUM]));
-	if (hooknum != NF_NETDEV_INGRESS)
-		return -EINVAL;
+		hooknum = ntohl(nla_get_be32(tb[NFTA_FLOWTABLE_HOOK_NUM]));
+		if (hooknum != NF_NETDEV_INGRESS)
+			return -EOPNOTSUPP;
+
+		priority = ntohl(nla_get_be32(tb[NFTA_FLOWTABLE_HOOK_PRIORITY]));
+
+		flowtable_hook->priority	= priority;
+		flowtable_hook->num		= hooknum;
+	} else {
+		if (tb[NFTA_FLOWTABLE_HOOK_NUM]) {
+			hooknum = ntohl(nla_get_be32(tb[NFTA_FLOWTABLE_HOOK_NUM]));
+			if (hooknum != flowtable->hooknum)
+				return -EOPNOTSUPP;
+		}
+
+		if (tb[NFTA_FLOWTABLE_HOOK_PRIORITY]) {
+			priority = ntohl(nla_get_be32(tb[NFTA_FLOWTABLE_HOOK_PRIORITY]));
+			if (priority != flowtable->data.priority)
+				return -EOPNOTSUPP;
+		}
 
-	priority = ntohl(nla_get_be32(tb[NFTA_FLOWTABLE_HOOK_PRIORITY]));
+		flowtable_hook->priority	= flowtable->data.priority;
+		flowtable_hook->num		= flowtable->hooknum;
+	}
 
 	if (tb[NFTA_FLOWTABLE_HOOK_DEVS]) {
 		err = nf_tables_parse_netdev_hooks(ctx->net,
@@ -6227,15 +6247,12 @@ static int nft_flowtable_parse_hook(const struct nft_ctx *ctx,
 			return err;
 	}
 
-	flowtable_hook->priority	= priority;
-	flowtable_hook->num		= hooknum;
-
 	list_for_each_entry(hook, &flowtable_hook->list, list) {
 		hook->ops.pf		= NFPROTO_NETDEV;
-		hook->ops.hooknum	= hooknum;
-		hook->ops.priority	= priority;
-		hook->ops.priv		= ft;
-		hook->ops.hook		= ft->type->hook;
+		hook->ops.hooknum	= flowtable_hook->num;
+		hook->ops.priority	= flowtable_hook->priority;
+		hook->ops.priv		= &flowtable->data;
+		hook->ops.hook		= flowtable->data.type->hook;
 	}
 
 	return err;
@@ -6363,7 +6380,7 @@ static int nft_flowtable_update(struct nft_ctx *ctx, const struct nlmsghdr *nlh,
 	int err;
 
 	err = nft_flowtable_parse_hook(ctx, nla[NFTA_FLOWTABLE_HOOK],
-				       &flowtable_hook, &flowtable->data);
+				       &flowtable_hook, flowtable, false);
 	if (err < 0)
 		return err;
 
@@ -6492,7 +6509,7 @@ static int nf_tables_newflowtable(struct net *net, struct sock *nlsk,
 		goto err3;
 
 	err = nft_flowtable_parse_hook(&ctx, nla[NFTA_FLOWTABLE_HOOK],
-				       &flowtable_hook, &flowtable->data);
+				       &flowtable_hook, flowtable, true);
 	if (err < 0)
 		goto err4;
 
@@ -6543,7 +6560,7 @@ static int nft_delflowtable_hook(struct nft_ctx *ctx,
 	int err;
 
 	err = nft_flowtable_parse_hook(ctx, nla[NFTA_FLOWTABLE_HOOK],
-				       &flowtable_hook, &flowtable->data);
+				       &flowtable_hook, flowtable, false);
 	if (err < 0)
 		return err;
 
-- 
2.20.1