From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 AF33E43E48C; Tue, 16 Jun 2026 15:25:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781623553; cv=none; b=dfPGFOPeTJg5XHXLIw+801N+u1nMvry0L1apQHt6O6hoPp3ehKRWXoEUa+iK1TN8TwoEfm5T/ZXcV95IlF769YhVIDeY/bRwtHB+OC8F+YXGxJV+E+HUv8fc4XmtWdyeAdnwCUZQKXoqbaanlL1tD4fyDSvWRcTdfUCkIEFJ80s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781623553; c=relaxed/simple; bh=IgIsSzRG35rn5pl/ZjFwBklNNtAhh4mcZpYjnHPbKzA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L5eAE9u6P1c4fv7dAjX5ZSYSwD87LhnStkvBK2smYKrmOVtXzVGI0AiCSJbX6weCA+zdCtNWDazHbLlnXHuw4WsoA4UfXTZsc7423SayhwWZwv9xqq4O35tLu7s4tmYAXr39WuX5JyCyzOQJtFwyeE1uBD2n6xe9kCqoTQuAOXo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=SlCG2rsQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="SlCG2rsQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9537A1F000E9; Tue, 16 Jun 2026 15:25:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781623552; bh=8WF+/nWzUZSaCNi9S5jg8W4d/koVBWTLsi7sLMltB2g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SlCG2rsQTIogW4YYFaKkq4J0cVZC7WF3oqYKcqzx8pRee+BnZjrkJWyHEH9oAhRop jzFNueHdqwbUu6GJ26jPCV4FAmJQPMdN+qB0lq8hvCLhowGr7RPjLV6H8z76SxXsmW kbMkv53sxnz2TRKId6nSV5W2WmfoDhy2tyB7KR0M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Davide Ornaghi , Pablo Neira Ayuso Subject: [PATCH 7.0 170/378] netfilter: nft_meta_bridge: fix stale stack leak via IIFHWADDR register Date: Tue, 16 Jun 2026 20:26:41 +0530 Message-ID: <20260616145119.278568839@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145109.744539446@linuxfoundation.org> References: <20260616145109.744539446@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davide Ornaghi commit c7d573551f9286100a055ef696cde6af54549677 upstream. NFT_META_BRI_IIFHWADDR declares its destination register with len = ETH_ALEN (6 bytes), which the register-init tracking rounds up to two 32-bit registers (8 bytes). nft_meta_bridge_get_eval() then does memcpy(dest, br_dev->dev_addr, ETH_ALEN), writing only 6 bytes and leaving the upper 2 bytes of the second register as uninitialised nft_do_chain() stack. A downstream load of that register span leaks those stale bytes to userspace. Zero the second register before the memcpy so the full declared span is written. Fixes: cbd2257dc96e ("netfilter: nft_meta_bridge: introduce NFT_META_BRI_IIFHWADDR support") Cc: stable@vger.kernel.org Signed-off-by: Davide Ornaghi Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/bridge/netfilter/nft_meta_bridge.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/bridge/netfilter/nft_meta_bridge.c +++ b/net/bridge/netfilter/nft_meta_bridge.c @@ -64,6 +64,8 @@ static void nft_meta_bridge_get_eval(con if (!br_dev) goto err; + /* ETH_ALEN (6) is shorter than the destination register span (8) */ + dest[1] = 0; memcpy(dest, br_dev->dev_addr, ETH_ALEN); return; default: