From fd3a459000557ff12c1d4b41f1bd30f439f6c942 Mon Sep 17 00:00:00 2001 From: Remi Pommarel Date: Fri, 24 Dec 2021 12:46:40 +0100 Subject: net: bridge: Get SIOCGIFBR/SIOCSIFBR ioctl working in compat mode 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 Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/bridge/br_ioctl.c | 75 ++++++++++++++++++++++++++++++++++----------------- 1 file changed, 50 insertions(+), 25 deletions(-) (limited to 'net/bridge') 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; -- cgit v1.2.3