From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (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 EA851381B1D; Wed, 25 Mar 2026 22:26:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774477597; cv=none; b=PUgJb+5LMV4V6Q/n8T0Ok/THDd27VjEMfNhHkvYnoegyfDsJtOOA8IPE/KSYALu0k3lD8z74scvvpckcYvwidKiay7EM6xpjvNqIMnHFBpgfxKYJ+O4yfDWOGkB75581EXTNAP2enjCShpgb4803rjVJv6BLiVpnv2Jr3IWVm80= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774477597; c=relaxed/simple; bh=K7RSrdEFZy6Z+RlJPtEraPlErH2kH671nvcT1Ug4334=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gtOV3iW9f9OEk9qwByR/EU3b5i088bCtAESxDdojN4t1ulTjcoi+VFxFzLUqjwcYpEl7km6yzDeBCsJ5L3Q+IVcVgaABCUB0j8Y5bEySTMLfhV4pBP9kEBXV/S5V4IdoIEG0VAVGoSNmCeJBHKEBW4a+P11myozr7pl0JlOFsec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=Is8pgJJv; arc=none smtp.client-ip=217.70.190.124 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) header.d=netfilter.org header.i=@netfilter.org header.b="Is8pgJJv" Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id C893B60180; Wed, 25 Mar 2026 23:26:28 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1774477589; bh=PIh+oFx3ncJBBFZxKgZDh/cS8gnROLybKH/NG8EuEkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Is8pgJJvbBEHBFukM7CRaU4lKTha55XlKQnijXNkRApB/2eCo5Tg8ittoZtX8r4l3 hjW9iNWZOv2WXsmbNeskBgL8Sfkd9z422DpHON5SKp59RLVLYBfKgJ5aBAzsryq/ZT 89pw5Um4jsEeT8W17S4ZqRTB4ycrjm8baZBtJYu9D5IWREiaCgVvWqkkA84L0o4Dpe 575V+5daaRrHr/hcrj5C/SyKZCNAHNFFPajbOL2dkrXkD/GZo7vz9RF+T54DDwMm0t omecxgkbAUwHG4D6Fo2M/xlrFcQSKtgHgSs9CF3PqnlluSjwKVgh6REww4VeM/wTKk JJ1fXv1Z9EsXg== 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@google.com, fw@strlen.de, horms@kernel.org Subject: [PATCH net 04/14] netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD Date: Wed, 25 Mar 2026 23:26:05 +0100 Message-ID: <20260325222615.637793-5-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260325222615.637793-1-pablo@netfilter.org> References: <20260325222615.637793-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Weiming Shi __build_packet_message() manually constructs the NFULA_PAYLOAD netlink attribute using skb_put() and skb_copy_bits(), bypassing the standard nla_reserve()/nla_put() helpers. While nla_total_size(data_len) bytes are allocated (including NLA alignment padding), only data_len bytes of actual packet data are copied. The trailing nla_padlen(data_len) bytes (1-3 when data_len is not 4-byte aligned) are never initialized, leaking stale heap contents to userspace via the NFLOG netlink socket. Replace the manual attribute construction with nla_reserve(), which handles the tailroom check, header setup, and padding zeroing via __nla_reserve(). The subsequent skb_copy_bits() fills in the payload data on top of the properly initialized attribute. Fixes: df6fb868d611 ("[NETFILTER]: nfnetlink: convert to generic netlink attribute functions") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_log.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index b35a90955e2e..fcbe54940b2e 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -647,15 +647,11 @@ __build_packet_message(struct nfnl_log_net *log, if (data_len) { struct nlattr *nla; - int size = nla_attr_size(data_len); - if (skb_tailroom(inst->skb) < nla_total_size(data_len)) + nla = nla_reserve(inst->skb, NFULA_PAYLOAD, data_len); + if (!nla) goto nla_put_failure; - nla = skb_put(inst->skb, nla_total_size(data_len)); - nla->nla_type = NFULA_PAYLOAD; - nla->nla_len = size; - if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) BUG(); } -- 2.47.3