Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB23AC433FE for ; Fri, 24 Dec 2021 11:42:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352604AbhLXLmI (ORCPT ); Fri, 24 Dec 2021 06:42:08 -0500 Received: from relay2-d.mail.gandi.net ([217.70.183.194]:36739 "EHLO relay2-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343860AbhLXLmH (ORCPT ); Fri, 24 Dec 2021 06:42:07 -0500 Received: (Authenticated sender: repk@triplefau.lt) by relay2-d.mail.gandi.net (Postfix) with ESMTPSA id 12E0B40005; Fri, 24 Dec 2021 11:42:03 +0000 (UTC) From: Remi Pommarel To: netdev@vger.kernel.org Cc: Roopa Prabhu , Nikolay Aleksandrov , Arnd Bergmann , "David S. Miller" , Jakub Kicinski , bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Remi Pommarel Subject: [PATCH net-next] net: bridge: Get SIOCGIFBR/SIOCSIFBR ioctl working in compat mode Date: Fri, 24 Dec 2021 12:46:40 +0100 Message-Id: <20211224114640.29679-1-repk@triplefau.lt> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In compat mode SIOC{G,S}IFBR ioctls were only supporting BRCTL_GET_VERSION returning an artificially version to spur userland tool to use SIOCDEVPRIVATE instead. But some userland tools ignore that and use SIOC{G,S}IFBR unconditionally as seen with busybox's brctl. Example of non working 32-bit brctl with CONFIG_COMPAT=y: $ brctl show brctl: SIOCGIFBR: Invalid argument Example of fixed 32-bit brctl with CONFIG_COMPAT=y: $ brctl show bridge name bridge id STP enabled interfaces br0 Signed-off-by: Remi Pommarel Co-developed-by: Arnd Bergmann Signed-off-by: Arnd Bergmann --- net/bridge/br_ioctl.c | 75 ++++++++++++++++++++++++++++--------------- net/socket.c | 20 ++---------- 2 files changed, 52 insertions(+), 43 deletions(-) diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index 891cfcf45644..5f3c1cf7f6ad 100644 --- a/net/bridge/br_ioctl.c +++ b/net/bridge/br_ioctl.c @@ -102,37 +102,56 @@ static int add_del_if(struct net_bridge *br, int ifindex, int isadd) return ret; } +#define BR_UARGS_MAX 4 +static int br_dev_read_uargs(unsigned long *args, size_t nr_args, + void __user **argp, void __user *data) +{ + int ret; + + if (nr_args < 2 || nr_args > BR_UARGS_MAX) + return -EINVAL; + + if (in_compat_syscall()) { + unsigned int cargs[BR_UARGS_MAX]; + int i; + + ret = copy_from_user(cargs, data, nr_args * sizeof(*cargs)); + if (ret) + goto fault; + + for (i = 0; i < nr_args; ++i) + args[i] = cargs[i]; + + *argp = compat_ptr(args[1]); + } else { + ret = copy_from_user(args, data, nr_args * sizeof(*args)); + if (ret) + goto fault; + *argp = (void __user *)args[1]; + } + + return 0; +fault: + return -EFAULT; +} + /* * Legacy ioctl's through SIOCDEVPRIVATE * This interface is deprecated because it was too difficult * to do the translation for 32/64bit ioctl compatibility. */ -int br_dev_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user *data, int cmd) +int br_dev_siocdevprivate(struct net_device *dev, struct ifreq *rq, + void __user *data, int cmd) { struct net_bridge *br = netdev_priv(dev); struct net_bridge_port *p = NULL; unsigned long args[4]; void __user *argp; - int ret = -EOPNOTSUPP; - - if (in_compat_syscall()) { - unsigned int cargs[4]; - - if (copy_from_user(cargs, data, sizeof(cargs))) - return -EFAULT; - - args[0] = cargs[0]; - args[1] = cargs[1]; - args[2] = cargs[2]; - args[3] = cargs[3]; - - argp = compat_ptr(args[1]); - } else { - if (copy_from_user(args, data, sizeof(args))) - return -EFAULT; + int ret; - argp = (void __user *)args[1]; - } + ret = br_dev_read_uargs(args, ARRAY_SIZE(args), &argp, data); + if (ret) + return ret; switch (args[0]) { case BRCTL_ADD_IF: @@ -301,6 +320,9 @@ int br_dev_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user case BRCTL_GET_FDB_ENTRIES: return get_fdb_entries(br, argp, args[2], args[3]); + + default: + ret = -EOPNOTSUPP; } if (!ret) { @@ -313,12 +335,15 @@ int br_dev_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user return ret; } -static int old_deviceless(struct net *net, void __user *uarg) +static int old_deviceless(struct net *net, void __user *data) { unsigned long args[3]; + void __user *argp; + int ret; - if (copy_from_user(args, uarg, sizeof(args))) - return -EFAULT; + ret = br_dev_read_uargs(args, ARRAY_SIZE(args), &argp, data); + if (ret) + return ret; switch (args[0]) { case BRCTL_GET_VERSION: @@ -337,7 +362,7 @@ static int old_deviceless(struct net *net, void __user *uarg) args[2] = get_bridge_ifindices(net, indices, args[2]); - ret = copy_to_user((void __user *)args[1], indices, + ret = copy_to_user(argp, indices, array_size(args[2], sizeof(int))) ? -EFAULT : args[2]; @@ -353,7 +378,7 @@ static int old_deviceless(struct net *net, void __user *uarg) if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; - if (copy_from_user(buf, (void __user *)args[1], IFNAMSIZ)) + if (copy_from_user(buf, argp, IFNAMSIZ)) return -EFAULT; buf[IFNAMSIZ-1] = 0; diff --git a/net/socket.c b/net/socket.c index 7f64a6eccf63..6b2a898055ca 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3233,21 +3233,6 @@ static int compat_ifr_data_ioctl(struct net *net, unsigned int cmd, return dev_ioctl(net, cmd, &ifreq, data, NULL); } -/* Since old style bridge ioctl's endup using SIOCDEVPRIVATE - * for some operations; this forces use of the newer bridge-utils that - * use compatible ioctls - */ -static int old_bridge_ioctl(compat_ulong_t __user *argp) -{ - compat_ulong_t tmp; - - if (get_user(tmp, argp)) - return -EFAULT; - if (tmp == BRCTL_GET_VERSION) - return BRCTL_VERSION + 1; - return -EINVAL; -} - static int compat_sock_ioctl_trans(struct file *file, struct socket *sock, unsigned int cmd, unsigned long arg) { @@ -3259,9 +3244,6 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock, return sock_ioctl(file, cmd, (unsigned long)argp); switch (cmd) { - case SIOCSIFBR: - case SIOCGIFBR: - return old_bridge_ioctl(argp); case SIOCWANDEV: return compat_siocwandev(net, argp); case SIOCGSTAMP_OLD: @@ -3290,6 +3272,8 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock, case SIOCGSTAMP_NEW: case SIOCGSTAMPNS_NEW: case SIOCGIFCONF: + case SIOCSIFBR: + case SIOCGIFBR: return sock_ioctl(file, cmd, arg); case SIOCGIFFLAGS: -- 2.33.0