From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH nf-next 3/4] netfilter: nf_tables: missing sanitization in data from userspace Date: Mon, 1 May 2017 10:58:02 +0200 Message-ID: <1493629083-2847-3-git-send-email-pablo@netfilter.org> References: <1493629083-2847-1-git-send-email-pablo@netfilter.org> To: netfilter-devel@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:48446 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S376359AbdEAI6S (ORCPT ); Mon, 1 May 2017 04:58:18 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 480B61F4B7E for ; Mon, 1 May 2017 10:58:11 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 3769DFF124 for ; Mon, 1 May 2017 10:58:11 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 1FA90FF2D0 for ; Mon, 1 May 2017 10:58:09 +0200 (CEST) In-Reply-To: <1493629083-2847-1-git-send-email-pablo@netfilter.org> Sender: netfilter-devel-owner@vger.kernel.org List-ID: Do not assume userspace always sends us NFT_DATA_VALUE for bitwise and cmp expressions. Although NFT_DATA_VERDICT does not make any sense, it is still possible to handcraft a netlink message using this incorrect data type. Signed-off-by: Pablo Neira Ayuso --- This patch replaces [nf-next,2/4] netfilter: nf_tables: remove nft_data_uninit() on NFT_DATA_VALUE. We cannot assume userspace sends us something right, so it may indeed use a verdict to compare/bitwise even if it doesn't make it sense, leading to a chain refcount leak. net/netfilter/nft_bitwise.c | 19 ++++++++++++++----- net/netfilter/nft_cmp.c | 12 ++++++++++-- 2 files changed, 24 insertions(+), 7 deletions(-) diff --git a/net/netfilter/nft_bitwise.c b/net/netfilter/nft_bitwise.c index 877d9acd91ef..96bd4f325b0f 100644 --- a/net/netfilter/nft_bitwise.c +++ b/net/netfilter/nft_bitwise.c @@ -83,17 +83,26 @@ static int nft_bitwise_init(const struct nft_ctx *ctx, tb[NFTA_BITWISE_MASK]); if (err < 0) return err; - if (d1.len != priv->len) - return -EINVAL; + if (d1.len != priv->len) { + err = -EINVAL; + goto err1; + } err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &d2, tb[NFTA_BITWISE_XOR]); if (err < 0) - return err; - if (d2.len != priv->len) - return -EINVAL; + goto err1; + if (d2.len != priv->len) { + err = -EINVAL; + goto err2; + } return 0; +err2: + nft_data_uninit(&priv->xor, d2.type); +err1: + nft_data_uninit(&priv->mask, d1.type); + return err; } static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr) diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c index 2b96effeadc1..8c9d0fb19118 100644 --- a/net/netfilter/nft_cmp.c +++ b/net/netfilter/nft_cmp.c @@ -201,10 +201,18 @@ nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) if (err < 0) return ERR_PTR(err); + if (desc.type != NFT_DATA_VALUE) { + err = -EINVAL; + goto err1; + } + if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) return &nft_cmp_fast_ops; - else - return &nft_cmp_ops; + + return &nft_cmp_ops; +err1: + nft_data_uninit(&data, desc.type); + return ERR_PTR(-EINVAL); } struct nft_expr_type nft_cmp_type __read_mostly = { -- 2.1.4