Commit 99ab9f84 authored by Phil Sutter's avatar Phil Sutter Committed by Florian Westphal
Browse files

netfilter: nf_tables: Don't allocate nft_rule_dump_ctx 



Since struct netlink_callback::args is not used by rule dumpers anymore,
use it to hold nft_rule_dump_ctx. Add a build-time check to make sure it
won't ever exceed the available space.

Signed-off-by: default avatarPhil Sutter <phil@nwl.cc>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
parent 8194d599

net/netfilter/nf_tables_api.c

+6 −13
Original line number Diff line number Diff line
@@ -3453,7 +3453,7 @@ static int __nf_tables_dump_rules(struct sk_buff *skb, 
				  const struct nft_table *table,

				  const struct nft_chain *chain)

{

	struct nft_rule_dump_ctx *ctx = cb->data;

	struct nft_rule_dump_ctx *ctx = (void *)cb->ctx;

	struct net *net = sock_net(skb->sk);

	const struct nft_rule *rule, *prule;

	unsigned int entries = 0;
@@ -3498,7 +3498,7 @@ static int nf_tables_dump_rules(struct sk_buff *skb, 
				struct netlink_callback *cb)

{

	const struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);

	struct nft_rule_dump_ctx *ctx = cb->data;

	struct nft_rule_dump_ctx *ctx = (void *)cb->ctx;

	struct nft_table *table;

	const struct nft_chain *chain;

	unsigned int idx = 0;
@@ -3553,42 +3553,35 @@ static int nf_tables_dump_rules(struct sk_buff *skb, 


static int nf_tables_dump_rules_start(struct netlink_callback *cb)

{

	struct nft_rule_dump_ctx *ctx = (void *)cb->ctx;

	const struct nlattr * const *nla = cb->data;

	struct nft_rule_dump_ctx *ctx = NULL;



	ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC);

	if (!ctx)

		return -ENOMEM;

	BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));



	if (nla[NFTA_RULE_TABLE]) {

		ctx->table = nla_strdup(nla[NFTA_RULE_TABLE], GFP_ATOMIC);

		if (!ctx->table) {

			kfree(ctx);

		if (!ctx->table)

			return -ENOMEM;

	}

	}

	if (nla[NFTA_RULE_CHAIN]) {

		ctx->chain = nla_strdup(nla[NFTA_RULE_CHAIN], GFP_ATOMIC);

		if (!ctx->chain) {

			kfree(ctx->table);

			kfree(ctx);

			return -ENOMEM;

		}

	}

	if (NFNL_MSG_TYPE(cb->nlh->nlmsg_type) == NFT_MSG_GETRULE_RESET)

		ctx->reset = true;



	cb->data = ctx;

	return 0;

}



static int nf_tables_dump_rules_done(struct netlink_callback *cb)

{

	struct nft_rule_dump_ctx *ctx = cb->data;

	struct nft_rule_dump_ctx *ctx = (void *)cb->ctx;



	kfree(ctx->table);

	kfree(ctx->chain);

	kfree(ctx);

	return 0;

}