From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 5/8] netfilter: nft_compat: do not dump private area
Date: Mon, 22 Oct 2018 22:07:21 +0200 [thread overview]
Message-ID: <20181022200724.25806-6-pablo@netfilter.org> (raw)
In-Reply-To: <20181022200724.25806-1-pablo@netfilter.org>
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: 0ca743a55991 ("netfilter: nf_tables: add compatibility layer for x_tables")
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nft_compat.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 32535eea51b2..768292eac2a4 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -290,6 +290,24 @@ nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
module_put(target->me);
}
+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;
@@ -297,7 +315,8 @@ 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;
@@ -532,7 +551,8 @@ 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;
--
2.11.0
next prev parent reply other threads:[~2018-10-23 4:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-22 20:07 [PATCH 0/8] Netfilter fixes for net Pablo Neira Ayuso
2018-10-22 20:07 ` [PATCH 1/8] netfilter: nft_set_rbtree: allow loose matching of closing element in interval Pablo Neira Ayuso
2018-10-22 20:07 ` [PATCH 2/8] netfilter: nft_osf: usage from output path is not valid Pablo Neira Ayuso
2018-10-22 20:07 ` [PATCH 3/8] netfilter: xt_TEE: fix wrong interface selection Pablo Neira Ayuso
2018-10-22 20:07 ` [PATCH 4/8] netfilter: xt_TEE: add missing code to get interface index in checkentry Pablo Neira Ayuso
2018-10-22 20:07 ` Pablo Neira Ayuso [this message]
2018-10-22 20:07 ` [PATCH 6/8] netfilter: xt_nat: fix DNAT target for shifted portmap ranges Pablo Neira Ayuso
2018-10-22 20:07 ` [PATCH 7/8] netfilter: nf_flow_table: remove flowtable hook flush routine in netns exit routine Pablo Neira Ayuso
2018-10-22 20:07 ` [PATCH 8/8] netfilter: nf_flow_table: do not remove offload when other netns's interface is down Pablo Neira Ayuso
2018-10-23 3:21 ` [PATCH 0/8] Netfilter fixes for net David Miller
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