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Commit 9089b2f0 authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso Committed by Greg Kroah-Hartman
Browse files

netfilter: nft_compat: do not dump private area 



[ Upstream commit d701d8117200399d85e63a737d2e4e897932f3b6 ]

Zero pad private area, otherwise we expose private kernel pointer to
userspace. This patch also zeroes the tail area after the ->matchsize
and ->targetsize that results from XT_ALIGN().

Fixes: 0ca743a5 ("netfilter: nf_tables: add compatibility layer for x_tables")
Reported-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent e6c540bf

net/netfilter/nft_compat.c

+22 −2
Original line number Diff line number Diff line
@@ -269,6 +269,24 @@ nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) 
	kfree(expr->ops);

}



static int nft_extension_dump_info(struct sk_buff *skb, int attr,

				   const void *info,

				   unsigned int size, unsigned int user_size)

{

	unsigned int info_size, aligned_size = XT_ALIGN(size);

	struct nlattr *nla;



	nla = nla_reserve(skb, attr, aligned_size);

	if (!nla)

		return -1;



	info_size = user_size ? : size;

	memcpy(nla_data(nla), info, info_size);

	memset(nla_data(nla) + info_size, 0, aligned_size - info_size);



	return 0;

}



static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)

{

	const struct xt_target *target = expr->ops->data;
@@ -276,7 +294,8 @@ static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr) 


	if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||

	    nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||

	    nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))

	    nft_extension_dump_info(skb, NFTA_TARGET_INFO, info,

				    target->targetsize, target->usersize))

		goto nla_put_failure;



	return 0;
@@ -504,7 +523,8 @@ static int __nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr, 


	if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||

	    nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||

	    nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))

	    nft_extension_dump_info(skb, NFTA_MATCH_INFO, info,

				    match->matchsize, match->usersize))

		goto nla_put_failure;



	return 0;