From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.180 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793425600; b=LQYvwsCkRfwTQwc0TSwgpBGUXFnZHCyP+bCA63g4te9lQ3UzwMfXlbYbr44THGNyWa5E EYrNVUmPvj34u9iIOvk8FiKELzxePJlt4gAAH8u/l1o8UdLLeLZJzSdyKlsvD88Heh3Sx JplYZ5FZmrmnEqpf9Vu/uJbGS9+VrfiqNGrYwecEG9KTmuBmhWuiDKpL6Mt7hlFCthWJj g1tMWBjNejfhnzo5XQhswLr3wTeb/M9xvpkicLH8MIXHihnxneQmc4ZBePZDudjH24SGP ndf2fMbSSOFmp4kU2MaUAO1KvHibC9Sw5OaAHZwwIjT0peEGV0CUa2CEUsTROShqkbg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793425600; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-Id:X-Mailer:MIME-Version: Content-Transfer-Encoding; bh=597SVjqFkP14STDOk7S4HpjKdXVmvh6EV5etFFqcGZ8=; b=OC/Hb6INWPem/n5LxqdENZ1EXpLwRGzPy40cpSMQb0jnluuj2FrLlwg2k6jfQa+Sr3Sh z21z8l5XILqTJy0EA5JOFIUPH/B1z9+maHB7udymm6ss6CoBFqwiQf9rbC21I+28rExL5 oqr0WzxGebCLL7xk8CcdeQScJotYR+F8H9snZFuLE+h8O5kuxx3E4hJpZdYfEo2Gp2GIT Ky/sn9Zg5nmXbjjoS92CjF8HK6QMnZ8qmiOUYZadXfF1lepAlJbnAKE1k3z18gZjM3KSk OrunnSQN5etrUGLuk8Yey8ZpNnL6j2ZzqUZU/FA88r06WV6m4hO1Uy0njpu17bT6JDA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b="ZUva/FSv"; arc=none smtp.remote-ip=74.125.82.180 Received: from mail-dy1-f180.google.com (mail-dy1-f180.google.com [74.125.82.180]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E74F606A31C for ; Sat, 31 Oct 2026 05:46:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 3E74F606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=ZUva/FSv Received: by mail-dy1-f180.google.com with SMTP id 5a478bee46e88-33fb4680717so841708eec.1 for ; Fri, 30 Oct 2026 22:46:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1793425599; x=1794030399; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=597SVjqFkP14STDOk7S4HpjKdXVmvh6EV5etFFqcGZ8=; b=ZUva/FSvcdQ7XFNlXANdr8aIblbb/KkHwYHR0ob47Nqip05qx5UMuj634PMBdXmGDg VvNhT3GT+TPs9EqkHHIGh8TPTMdTkHv95G+7OEcx8eLom7RPmHzBnm7IF4G+3rwR0L29 atW0lHww1byrkwPqMyHf9N1NFr/HLyqKNaGpU81C6h/Dobsmjy01f2FKEY4sy0O44hjv HWm8iGLcp84O0SrKBVpSmyEt7VNyVNysUbo2+GSFNNpUX6dfyrFWRrbgpk9onF08cFKx 2idQlIM/mgOGTatN19cnx1PvwUJA4tMUEvbFh95UL+6O3TtjmCGVaEbeFVbIjTVUCjkk bsVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793425599; x=1794030399; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=597SVjqFkP14STDOk7S4HpjKdXVmvh6EV5etFFqcGZ8=; b=b9lPMlkfGkUdcBzjChmwcjjUuwkJ0JBfP3A0AlV1HGTlHJVsNCFL0KJRF82fKCr/B5 Jlk29brUtkaQpwYxnbYxQSkjXDkd3nRtz9nabjbiKBYBRZcRwR69oGie1HowaSRT9CAj dI2+qCikv6ysh5zYL67dOfL6GuzwGIfZstOr7ShrIxUajl8xrzTiRgTVG5OD2S+K3g1v zM21d7dtPHVd9C2D9/o9x6TmkdDsn+A2fiVHnhkj57rF9qxNmxwOfyCwnARS7x7UzTlc +UA+gksdXVviuq6ybA4qu9RNq7DbtKcQ1IF6vPT7gckSNIH4EQETmjZDpvdjLmnYtVHs q5Iw== X-Forwarded-Encrypted: i=1; AKwUvByrMSP4HYvB9fGK6a30SRJH1MZDdQFam2J6NQ+s7OojiCsyjO/lSzXz2rTeUCqky6LMyvrwLqx9FnhBPJM=@vger.kernel.org X-Gm-Message-State: AFq9FYIACjaCiEwegikWBReqTgluYLx5u5NZUhpbLUFqsvjsq1PmdVAG m27RmJJ/SDLU0OUGzwgfhiOH3N82V2MWSkdY6+0zB4iJsQzmxoBfDcvf X-Gm-Gg: AYBFou1SdqRMBswzBi24+knZ01X4JvWBa251/0mXqQAh4B3IUGxnFaNV0Y+wPmNGor4 uTVUklKwxqfpBXnvE/5YHz6zdaRnstlHzCqJEMrEHsZ7qm3F6W9LKQobkLEJPRtJv3L6caH0nAQ 0rwY/uiq1CB6k9Eo7+SGRCE5uoHoyfjtGZe5LGVbD5k7wwSB9vvV5qD5rl18G4t2J12/MmJBIQe MXSLASYpn6sPoom1Uf7dYWl4/GNb4RMsJWuZIzFQAWVAp7PUeoVdsux9YaH5t09Ynh7xwnkzPip qjdFa3KCsb9N8zLBMEmB0WN2eXyy9CTkVp8z9eGtrHaK2njbpo0bhMj8IhYGAABBFSFlgpX4lYr FL4KQyJUzs4yWDX0knwqXlSHpD/57crMQMf/AHMXJM8pjvnRMz5fBvn4mS5qGiuZsI4x0ssqbgY Ro7ni87efCsGrDsborYRG/pV2M2Bf+mX//ZTkcaE6sI1tFNKf+uxuBrs09s02bX65cxfI2Y1yyi op2wGFWMAzLd6RWFa6wq+77kGbPDN4L/x+Gym199YR5TDm0tQmEwp2RHLwrEiKe/6gA2obyOaoI UggtsLK6skDVaJ3pj55+wK01ETnaMirHq2xn5KwR+AmTl7IfDW6fXNMyQM6ptgQioihiiwZl4Yb L/Vrrhcq20FE3KpEcC88OvKnlYEbPZzCSZZXygEo2UtTcYqSzM3AMv1JtF8rTLbr92tb9rHpFbw == X-Received: by 2002:a05:693c:8392:10b0:361:39c0:c393 with SMTP id 5a478bee46e88-36a42340afemr7113890eec.13.1793425599269; Fri, 30 Oct 2026 22:46:39 -0700 (PDT) Received: from ramen-dev-security-2.asia-south1-c.c.ramen-dev-345017.internal (90.156.200.35.bc.googleusercontent.com. [35.200.156.90]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-36a429018casm11668877eec.14.2026.10.30.22.46.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Oct 2026 22:46:38 -0700 (PDT) From: Anil Kaushik To: netdev@vger.kernel.org Cc: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Ido Schimmel , Nicolas Dichtel , Jacob Keller , Jiri Pirko , XingWang Xiang , Alice Ryhl , linux-kernel@vger.kernel.org Subject: [PATCH net v2 0/2] genetlink: fix joining multicast groups no family owns Date: Sat, 31 Oct 2026 05:46:30 +0000 Message-Id: <20261031054632.3697295-1-anilkaushikwireless@gmail.com> X-Mailer: git-send-email 2.25.1 X-Mailing-List: linux-kernel@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 genl_bind() checks the GENL_MCAST_CAP_* flags of a group only when a family owns it. A socket can join a free group ID and stay a member when a family with those flags gets the ID later. Patch 1 rejects joins to group IDs that no family owns. Patch 2 clears the members of the group IDs when a family is given them. This covers the race Sashiko found on v1, where the family is unregistered between genl_bind() and the point where the membership bit is set. One case is left. If the family is unregistered and a family with GENL_MCAST_CAP_* flags gets the ID, both inside that window, the bit is set after the clear. Closing it needs the check and the update under one lock in af_netlink.c. I will send that separately. Tested as an unprivileged user, with an msleep() added after the bind callback in netlink_setsockopt() and a test family that registers again with GENL_MCAST_CAP_NET_ADMIN: v1 v2 unregister in the window, register later member not member unregister and register in the window member member The test from v1 (join all free IDs, then load gtp and drop_monitor) gives the same result as before, and patch 2 alone also fixes it. Changes in v2: - New patch 2 (Sashiko). - Patch 1: no change, added Reviewed-by tags. v1: https://lore.kernel.org/netdev/20261029062214.3407223-1-anilkaushikwireless@gmail.com/ Anil Kaushik (2): genetlink: Reject joining multicast groups no family owns genetlink: Clear stale members when assigning multicast group IDs net/netlink/genetlink.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) -- 2.25.1