From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 70C3C3D3D06; Wed, 8 Apr 2026 18:14:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672059; cv=none; b=D2viwuaV9/9ELwieJMEZLVFPrNtbDaVFC/UWfzF+mc/ElLIkwtRdzQgGDNp03irw3koPkXrOMqzgmYf6Pcqcxuu4qqj4e6KY5X8rVkstNxwUs0sBdjK8uVl9TyGnN/p9u37m/wImGbXCoDY7YXnKd+o1gvpcyN/dwV292CpCdn4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672059; c=relaxed/simple; bh=MJRZZyHoT8CsCoZEpzlnP3diI3Ko/Uf8ey9HW+v9TMo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Z93XMcs9nym3NH+wy92FsOYtiLBsem813SpOAGSd0z5wRM5R/Z/n5eRIxP+5hGdIm3EdwFG5Y5X/SvSqrPyp75dABz7WTBT6eFrGXT1CglnD2F5JEIpBkUNB1ib0mzqQ2uKiS4EextYm+8xyqwlGeQjAqa+yQulvgcbThyd3B3k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NHvNq2QL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="NHvNq2QL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0772DC19421; Wed, 8 Apr 2026 18:14:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1775672059; bh=MJRZZyHoT8CsCoZEpzlnP3diI3Ko/Uf8ey9HW+v9TMo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NHvNq2QLTiyYkXSJbwAFfQGdI5Ds8yTGEYrl2cu6rUoSfF31SydVWydPkzhpFQDhd ACbz7fLaUkJVXAb+k+n3GkvNPfUBmuknrXmX6JJfvZ2scENM0Z1XnmplJpXu5LH/ds zfF2b4uxxVGdxRCjOEdMTKIWa/Wy145Hs8MlCYAc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Florian Westphal , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 6.1 174/312] netfilter: x_tables: restrict xt_check_match/xt_check_target extensions for NFPROTO_ARP Date: Wed, 8 Apr 2026 20:01:31 +0200 Message-ID: <20260408175940.263415448@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408175933.715315542@linuxfoundation.org> References: <20260408175933.715315542@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pablo Neira Ayuso [ Upstream commit 3d5d488f11776738deab9da336038add95d342d1 ] Weiming Shi says: xt_match and xt_target structs registered with NFPROTO_UNSPEC can be loaded by any protocol family through nft_compat. When such a match/target sets .hooks to restrict which hooks it may run on, the bitmask uses NF_INET_* constants. This is only correct for families whose hook layout matches NF_INET_*: IPv4, IPv6, INET, and bridge all share the same five hooks (PRE_ROUTING ... POST_ROUTING). ARP only has three hooks (IN=0, OUT=1, FORWARD=2) with different semantics. Because NF_ARP_OUT == 1 == NF_INET_LOCAL_IN, the .hooks validation silently passes for the wrong reasons, allowing matches to run on ARP chains where the hook assumptions (e.g. state->in being set on input hooks) do not hold. This leads to NULL pointer dereferences; xt_devgroup is one concrete example: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000044: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000220-0x0000000000000227] RIP: 0010:devgroup_mt+0xff/0x350 Call Trace: nft_match_eval (net/netfilter/nft_compat.c:407) nft_do_chain (net/netfilter/nf_tables_core.c:285) nft_do_chain_arp (net/netfilter/nft_chain_filter.c:61) nf_hook_slow (net/netfilter/core.c:623) arp_xmit (net/ipv4/arp.c:666) Kernel panic - not syncing: Fatal exception in interrupt Fix it by restricting arptables to NFPROTO_ARP extensions only. Note that arptables-legacy only supports: - arpt_CLASSIFY - arpt_mangle - arpt_MARK that provide explicit NFPROTO_ARP match/target declarations. Fixes: 9291747f118d ("netfilter: xtables: add device group match") Reported-by: Xiang Mei Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/x_tables.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index c842ec693dad4..650cb725ba271 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -501,6 +501,17 @@ int xt_check_match(struct xt_mtchk_param *par, par->match->table, par->table); return -EINVAL; } + + /* NFPROTO_UNSPEC implies NF_INET_* hooks which do not overlap with + * NF_ARP_IN,OUT,FORWARD, allow explicit extensions with NFPROTO_ARP + * support. + */ + if (par->family == NFPROTO_ARP && + par->match->family != NFPROTO_ARP) { + pr_info_ratelimited("%s_tables: %s match: not valid for this family\n", + xt_prefix[par->family], par->match->name); + return -EINVAL; + } if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) { char used[64], allow[64]; @@ -1016,6 +1027,18 @@ int xt_check_target(struct xt_tgchk_param *par, par->target->table, par->table); return -EINVAL; } + + /* NFPROTO_UNSPEC implies NF_INET_* hooks which do not overlap with + * NF_ARP_IN,OUT,FORWARD, allow explicit extensions with NFPROTO_ARP + * support. + */ + if (par->family == NFPROTO_ARP && + par->target->family != NFPROTO_ARP) { + pr_info_ratelimited("%s_tables: %s target: not valid for this family\n", + xt_prefix[par->family], par->target->name); + return -EINVAL; + } + if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) { char used[64], allow[64]; -- 2.53.0