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 074FD44E66F; Thu, 30 Jul 2026 15:21:29 +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=1785424890; cv=none; b=beVXUz7YuYDCfxtUNplcAL4g/1jg9vV7shvmNOdGr/xBARqUWv7AZr+gAtpeY6KeH2hgf8oOVXnixO/WZJ9Kj3cMwe2EHXSt+zlZ06S/6q/FPSxWe20WR6NMsmUscNxtPH/mOewxQ+xYrXr2eWPJXt67UT6AI5kM501JCoR+B7o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785424890; c=relaxed/simple; bh=Iwrusthf9GeWKizwbqnD+VSiHo3QgpmX0NkNG3CWdTI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QNZs42Cv+zOxpQjf9QEQllZQ1huRmQXy/CfgNgwRxfk4ySFNvKMBqmZ0qg5MOGXK2v42i+cnh50a6KGP/O1W3M8w0jbu6iag/AbtNmYQHkVZBqXKnGh1m1XBSBPfR6kNdaudnEcmLKr0d89FvNmyHo/UGhbTZyYPhoMY2Toj3bk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1D3byVeX; 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="1D3byVeX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FF0A1F00A3D; Thu, 30 Jul 2026 15:21:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785424888; bh=VSMc05coZjaGR1Z+S1TLisqH5c8xgY79H5jsmluL4Wg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1D3byVeXbjUlKiUjfbqGU3iBUIbNoeEs4yi0Fr6wKzjEudlNuT0vdi1i/1B1z/SS4 NVzN+w0zGP0SlfM4Z0RGI2S6R1evAxX9FxmPi48tDJOBZuyIY8bv4Z9tV7IXUwWF5s Elmgez++dQu4iWeQNUjFyCWUOztUIJsEf7HzR8pU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuan Tan , Yifan Wu , Juefei Pu , Xin Liu , Qi Tang , Zhiling Zou , Ren Wei , Xin Long , Jakub Kicinski Subject: [PATCH 6.18 508/675] sctp: avoid auth_enable sysctl UAF during netns teardown Date: Thu, 30 Jul 2026 16:13:58 +0200 Message-ID: <20260730141455.926184178@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141445.110192266@linuxfoundation.org> References: <20260730141445.110192266@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhiling Zou commit f8d5e7846025f4ab15a461235f8ebae9094a361a upstream. proc_sctp_do_auth() updates the SCTP control socket after changing net.sctp.auth_enable. The handler gets the per-net SCTP state from ctl->data, so an already opened sysctl file can still target a network namespace while that namespace is being torn down. SCTP previously registered its per-net sysctls from sctp_defaults_init(), while the control socket is created later from sctp_ctrlsock_init(). This exposed a window during initialization where auth_enable was writable before net->sctp.ctl_sock existed, and a teardown window where auth_enable stayed writable after inet_ctl_sock_destroy() had released the control socket. Move the per-net SCTP sysctl registration into sctp_ctrlsock_init() after sctp_ctl_sock_init() succeeds, and unregister the sysctl table before destroying the control socket in sctp_ctrlsock_exit(). If sysctl registration fails after the control socket was created, destroy the control socket in the same init path. Make sctp_sysctl_net_unregister() tolerate a missing header and clear the saved pointer so init-error and exit paths can safely share the unregister helper. Fixes: 15649fd5415e ("sctp: sysctl: auth_enable: avoid using current->nsproxy") Cc: stable@vger.kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Co-developed-by: Qi Tang Signed-off-by: Qi Tang Signed-off-by: Zhiling Zou Signed-off-by: Ren Wei Acked-by: Xin Long Link: https://patch.msgid.link/390cd5e91ed60eea27b0b64d0468301a9e73b808.1784033357.git.roxy520tt@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/sctp/protocol.c | 20 ++++++++++++-------- net/sctp/sysctl.c | 9 +++++++-- 2 files changed, 19 insertions(+), 10 deletions(-) --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -1410,10 +1410,6 @@ static int __net_init sctp_defaults_init net->sctp.l3mdev_accept = 1; #endif - status = sctp_sysctl_net_register(net); - if (status) - goto err_sysctl_register; - /* Allocate and initialise sctp mibs. */ status = init_sctp_mibs(net); if (status) @@ -1447,8 +1443,6 @@ err_init_proc: cleanup_sctp_mibs(net); #endif err_init_mibs: - sctp_sysctl_net_unregister(net); -err_sysctl_register: return status; } @@ -1463,7 +1457,6 @@ static void __net_exit sctp_defaults_exi net->sctp.proc_net_sctp = NULL; #endif cleanup_sctp_mibs(net); - sctp_sysctl_net_unregister(net); } static struct pernet_operations sctp_defaults_ops = { @@ -1477,16 +1470,27 @@ static int __net_init sctp_ctrlsock_init /* Initialize the control inode/socket for handling OOTB packets. */ status = sctp_ctl_sock_init(net); - if (status) + if (status) { pr_err("Failed to initialize the SCTP control sock\n"); + return status; + } + + status = sctp_sysctl_net_register(net); + if (status) { + inet_ctl_sock_destroy(net->sctp.ctl_sock); + net->sctp.ctl_sock = NULL; + } return status; } static void __net_exit sctp_ctrlsock_exit(struct net *net) { + sctp_sysctl_net_unregister(net); + /* Free the control endpoint. */ inet_ctl_sock_destroy(net->sctp.ctl_sock); + net->sctp.ctl_sock = NULL; } static struct pernet_operations sctp_ctrlsock_ops = { --- a/net/sctp/sysctl.c +++ b/net/sctp/sysctl.c @@ -615,11 +615,16 @@ int sctp_sysctl_net_register(struct net void sctp_sysctl_net_unregister(struct net *net) { + struct ctl_table_header *header = net->sctp.sysctl_header; const struct ctl_table *table; - table = net->sctp.sysctl_header->ctl_table_arg; - unregister_net_sysctl_table(net->sctp.sysctl_header); + if (!header) + return; + + table = header->ctl_table_arg; + unregister_net_sysctl_table(header); kfree(table); + net->sctp.sysctl_header = NULL; } static struct ctl_table_header *sctp_sysctl_header;