From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.70.190.124 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793782966; b=Rd2gEEazv1HAyPWhSYVqs0Q0jh0fb6100vYKY2vDfg3oNn7aWLLU0tlo8/d+dJowf+iM epG1wDoGTVmfVBD1LR8yYibXHiH4kjneXoCBkF81go2X0MFaQoLw0jUWil8e/0USvczND LglRUuHcJva86jQFnhQ9BviXCT6ADw45Rn9oku4dE8ECy5C8pL7ukNRytyXabllyIsArg yRSg+N8qogsltgXmjkricYgKil0ba3I7XP+nkTLZLiuEQwo5Sy2Z9Z541iDnmPVEjKT/b GQhxw4h2XlRRDOPJ1m9VTUl99NRDujlL3gmEb2vbSxXHtay7/BOFyxvqdApx3sOcvkw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793782966; h=DMARC-Filter:DKIM-Signature:Received:From:To:Cc:Subject:Date: Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding:X-Spam-Status:X-Spam-Checker-Version; bh=XClvt/H6YMd9+Exyu1R4Oy60MLFqQ2fw95DTYxl2feU=; b=UxLn6ujMlv3SvPt2QPlxTLRysW2DLeRGop9YICZjQNWQExgkg5BDv4C/xANxNSpLIBCL qiUw27QAgiGeVIlM/YnDfoxyKH5j8BxBJAnMf2wSkBbCYwQM66ol5Iwy6gfefu1eC0yuo szZNXrJU+uKbgSk4UC25kK63/AoayWieA/BYAFbsnuIPnPU7sFo/2yt1maE0qBaeGQDkI VRFf4zrgBK5Nf5YtXNmRue+trrXnYBbPt8X00OgO75sQLwtZc9IC8k2evk9SCCZ93zMwj 0WvPEh3tsB0NSMl4lMkfmjD+3I8pR4zvqQHgp8zsX+Xqu3DstTBdUGex2i/B3y3NNAQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass header.d=netfilter.org header.i=@netfilter.org header.a=rsa-sha256 header.s=2025 header.b="P7mUy/cm"; arc=none smtp.remote-ip=217.70.190.124 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7345C606D819; Wed, 4 Nov 2026 09:02:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 7345C606D819 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=netfilter.org header.i=@netfilter.org header.a=rsa-sha256 header.s=2025 header.b=P7mUy/cm DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1793782964; bh=XClvt/H6YMd9+Exyu1R4Oy60MLFqQ2fw95DTYxl2feU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P7mUy/cmJf1PiTJZs6KLC4gLCNsW0jTI/w5qbv59JTALAq3CLqfjil5dmpX6ee3ch 0cwM2HNGIqG7RX7PjKGdkwc+BShrvMKXBFZJ3WIvAnT6OJA4EydQQZspqcQWECVGOd EpSuxBKuWCnZVA0HgukkU2PAuWOnqxnw44Ga+HWL76bkAvR7kOOfDLZ1OnM9UJthmj gfAIFYB+Ak1N7aj6bPfQVaNTy4qKyQNSpCi4gHZEaSaRj5KqK2COejodrt/GIvxG91 hde5N7CYRIbVOhwYZTztTBWd1m8iARB+dacmL0NPB5W8x8E5h+8ROERz2ybKzYSfcq kHo3GEYZIm9rQ== Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id 66E916008A; Wed, 4 Nov 2026 10:02:44 +0100 (CET) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@kernel.org, horms@kernel.org, fw@strlen.de, ja@ssi.bg Subject: [PATCH net 09/13] netfilter: x_tables: check target name before accessing verdict Date: Wed, 4 Nov 2026 10:02:20 +0100 Message-ID: <20261104090224.750548-10-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261104090224.750548-1-pablo@netfilter.org> References: <20261104090224.750548-1-pablo@netfilter.org> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Fernando Fernandez Mancera Non-standard targets may contain only struct xt_entry_target. mark_source_chains() nevertheless reads the target as an xt_standard_target before checking its name, potentially reading four bytes beyond a header-only target. Check that the target is standard before reading its verdict. Non-standard targets remain handled as fallthrough rules. See the following KASAN trace: BUG: KASAN: slab-out-of-bounds in translate_table+0x1660/0x1a40 [ip6_tables] Read of size 4 at addr ffff88800ed56ff8 by task rep/432 Call Trace: kasan_report+0xfa/0x120 translate_table+0x1660/0x1a40 [ip6_tables] do_ip6t_set_ctl+0x667/0xa76 [ip6_tables] nf_setsockopt+0x77/0xd0 do_sock_setsockopt+0x118/0x490 __sys_setsockopt+0xe4/0x160 __x64_sys_setsockopt+0xbd/0x190 do_syscall_64+0xde/0x4f0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Allocated by task 432: kasan_save_stack+0x2f/0x50 __kasan_kmalloc+0x7f/0x90 __kvmalloc_node_noprof+0x1b1/0x5c0 xt_alloc_table_info+0x3c/0xa0 do_ip6t_set_ctl+0x5ee/0xa76 [ip6_tables] nf_setsockopt+0x77/0xd0 do_sock_setsockopt+0x118/0x490 __sys_setsockopt+0xe4/0x160 __x64_sys_setsockopt+0xbd/0x190 do_syscall_64+0xde/0x4f0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: VEGA Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/arp_tables.c | 5 +++-- net/ipv4/netfilter/ip_tables.c | 5 +++-- net/ipv6/netfilter/ip6_tables.c | 5 +++-- 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index cf747e1e17a3..7ff3d1f0ffd4 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -371,11 +371,12 @@ static int mark_source_chains(const struct xt_table_info *newinfo, e->counters.pcnt = pos; pos += size; } else { - int newpos = t->verdict; + int newpos; if (strcmp(t->target.u.user.name, XT_STANDARD_TARGET) == 0 && - newpos >= 0) { + t->verdict >= 0) { + newpos = t->verdict; /* This a jump; chase it. */ if (!xt_find_jump_offset(offsets, newpos, newinfo->number)) diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 809441cedced..b302bd77180a 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -422,11 +422,12 @@ mark_source_chains(const struct xt_table_info *newinfo, e->counters.pcnt = pos; pos += size; } else { - int newpos = t->verdict; + int newpos; if (strcmp(t->target.u.user.name, XT_STANDARD_TARGET) == 0 && - newpos >= 0) { + t->verdict >= 0) { + newpos = t->verdict; /* This a jump; chase it. */ if (!xt_find_jump_offset(offsets, newpos, newinfo->number)) diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 313c4aac377a..010baaa60665 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -440,11 +440,12 @@ mark_source_chains(const struct xt_table_info *newinfo, e->counters.pcnt = pos; pos += size; } else { - int newpos = t->verdict; + int newpos; if (strcmp(t->target.u.user.name, XT_STANDARD_TARGET) == 0 && - newpos >= 0) { + t->verdict >= 0) { + newpos = t->verdict; /* This a jump; chase it. */ if (!xt_find_jump_offset(offsets, newpos, newinfo->number)) -- 2.47.3