From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from oss.cyber.gouv.fr (oss.cyber.gouv.fr [51.159.188.251]) (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 3731628C009; Fri, 21 Aug 2026 20:29:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=51.159.188.251 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787344172; cv=none; b=lEJUOYpV3jUX5+nGW7w2DW10LQj2BmxcmCSbANPhclBn2l8QcvcZqqqCchYGBJrn+Vp7ImeGJPFG9Rcb5a0elDTtd+oMBvK9sR8ZVmGxvZKk2o/5QoPFIRM1g6xqmk5iMEzncwxnlvCt+YoKF94nvYgXvAG/aC/2qR/Fsx5E1NE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787344172; c=relaxed/simple; bh=5Z7zTShx/tz8zQU68ki8h3ljCOiWq2XceVd8PCQm8sk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=pk73+lwosu859llJKmq3sgKB36ddc1n+QzFFd9Sk1eUG4H7p5mhQsey0qMbiMa9+U3bCQQGEkk3mVTSBJGzxvGahWrCrmE6LZZjCfoVVbcuFKVKzl0nDgrSzy+clVhIJDdW4q8Ms3jgvG8Y0m3TWBskGtrDvYtyMyuJHDhNTVK4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=oss.cyber.gouv.fr; spf=pass smtp.mailfrom=oss.cyber.gouv.fr; dkim=pass (2048-bit key) header.d=oss.cyber.gouv.fr header.i=@oss.cyber.gouv.fr header.b=ZJZuKDWr; arc=none smtp.client-ip=51.159.188.251 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=oss.cyber.gouv.fr Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.cyber.gouv.fr Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oss.cyber.gouv.fr header.i=@oss.cyber.gouv.fr header.b="ZJZuKDWr" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=oss.cyber.gouv.fr; s=default; h=Content-Transfer-Encoding:Content-Type: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=GJVYThdLX6flGpGPc+xAe8iCpnn+ESplzc1fhpKsD7M=; b=ZJZuKDWrb2je8EOYNJ+W2Dh5wL nRMwlo2YPo2Q1FuJy1w+0v2XSUsvDplBEFh+KzCjf4MpFVJVNZxuMfdwaaoq1tmB85JYORxGFCOrB 3Bt8si65z9wRWzvXNS8BlkmEaCpKL/TbVg6JjO7IIdGzyCGKF8YMOOY/TFjj8jDa29WKkQeI40D2I KRplknwA7fAuKQ/lDaSjC+KcckXZxfhiZk54+ZnxgcivpuKxB/2+Tdx1DMtyLV8xw7oQzbPkuc6K7 dO1BTDFMN/tuLaX0BYHdddbnCaxn0Fe4VaNXis+dZCYwOEy2HhxxAUL9ur9W5i6ZjTo5OQ2gUUm2O HmwLDM3g==; Received: from [151.115.150.205] (port=58992 helo=gepetto..) by pf-012.whm.fr-par.scw.cloud with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.99.5) (envelope-from ) id 1wxVrk-0000000EXYi-367R; Fri, 21 Aug 2026 22:29:28 +0200 From: =?UTF-8?q?J=C3=A9r=C3=A9my=20Jean?= To: Subash Abhinov Kasiviswanathan , Sean Tranchetti Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?J=C3=A9r=C3=A9my=20Jean?= Subject: [PATCH] net: qualcomm: rmnet: require real-netns admin for bridging Date: Fri, 21 Aug 2026 20:28:46 +0000 Message-ID: <20260821202845.4053530-2-Jeremy.Jean@oss.cyber.gouv.fr> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - pf-012.whm.fr-par.scw.cloud X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - oss.cyber.gouv.fr X-Get-Message-Sender-Via: pf-012.whm.fr-par.scw.cloud: authenticated_id: jeremy.jean@oss.cyber.gouv.fr X-Authenticated-Sender: pf-012.whm.fr-par.scw.cloud: jeremy.jean@oss.cyber.gouv.fr X-Source: X-Source-Args: X-Source-Dir: An rmnet device remains linked to its real device after it is moved to a different network namespace. When it is used as a master, rmnet_add_bridge() follows that pointer and switches the real device's port to bridge mode. The rtnetlink master operation only requires CAP_NET_ADMIN in the namespace holding the visible rmnet and slave devices. A caller privileged only there can therefore bridge an attacker-controlled interface to the real device in another namespace, receiving and transmitting raw traffic across the namespace boundary. Require CAP_NET_ADMIN in the network namespace of the real device before configuring the bridge. Fixes: 60d58f971c10 ("net: qualcomm: rmnet: Implement bridge mode") Assisted-by: Codex:gpt-5 Signed-off-by: Jérémy Jean --- drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c index bed6f63facf2..45e6c16a5a70 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c @@ -441,6 +441,14 @@ int rmnet_add_bridge(struct net_device *rmnet_dev, struct rmnet_port *port, *slave_port; int err; + /* + * The rtnl path only checks CAP_NET_ADMIN against dev_net(rmnet_dev), + * but bridge mode below controls real_dev, which may live in another + * netns. + */ + if (!rtnl_dev_link_net_capable(rmnet_dev, dev_net(real_dev))) + return -EPERM; + port = rmnet_get_port_rtnl(real_dev); /* If there is more than one rmnet dev attached, its probably being