Remi Pommarel
2021-Dec-23 11:00 UTC
[Bridge] [PATCH net] net: bridge: fix ioctl old_deviceless bridge argument
On Wed, Dec 22, 2021 at 10:52:20PM +0100, Arnd Bergmann wrote:> On Wed, Dec 22, 2021 at 8:13 PM Remi Pommarel <repk at triplefau.lt> wrote:[...]> > The intention of my broken patch was to make it work for compat mode as I did > in br_dev_siocdevprivate(), as this is now the only bit that remains broken. > > This could be done along the lines of the patch below, if you see any value in > it. (not tested, probably not quite right).Oh ok, because SIOC{S,G}IFBR compat ioctl was painfully done with old_bridge_ioctl() I didn't think those needed compat. So I adapted and fixed your patch to get that working. Here is my test results. With my initial patch only : - 64bit busybox's brctl (working) # brctl show bridge name bridge id STP enabled interfaces br0 8000.000000000000 n - CONFIG_COMPAT=y + 32bit busybox's brctl (not working) # brctl show brctl: SIOCGIFBR: Invalid argument With both my intial patch and the one below : - 64bit busybox's brctl (working) # brctl show bridge name bridge id STP enabled interfaces br0 8000.000000000000 n - CONFIG_COMPAT=y + 32bit busybox's brctl (working) # brctl show bridge name bridge id STP enabled interfaces br0 8000.000000000000 n If you think this has enough value to fix those compatility issues I can either send the below patch as a V2 replacing my initial one for net or sending it as a separate patch for net-next. What would you rather like ? Thanks -- Remi diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index ca02db813c72..cbb373acf294 100644 --- a/net/bridge/br_ioctl.c +++ b/net/bridge/br_ioctl.c @@ -101,37 +101,56 @@ 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: @@ -300,6 +319,9 @@ 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) { @@ -312,12 +334,15 @@ 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: @@ -336,7 +361,7 @@ 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, args[2]*sizeof(int)) ? -EFAULT : args[2]; kfree(indices); @@ -351,7 +376,7 @@ 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 d9d036cad388..f5b107c5cb32 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3278,21 +3278,6 @@ 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) { @@ -3304,9 +3289,6 @@ 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: @@ -3335,6 +3317,8 @@ 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:
Arnd Bergmann
2021-Dec-23 11:38 UTC
[Bridge] [PATCH net] net: bridge: fix ioctl old_deviceless bridge argument
On Thu, Dec 23, 2021 at 12:00 PM Remi Pommarel <repk at triplefau.lt> wrote:> > On Wed, Dec 22, 2021 at 10:52:20PM +0100, Arnd Bergmann wrote: > > On Wed, Dec 22, 2021 at 8:13 PM Remi Pommarel <repk at triplefau.lt> wrote: > [...] > > > > The intention of my broken patch was to make it work for compat mode as I did > > in br_dev_siocdevprivate(), as this is now the only bit that remains broken. > > > > This could be done along the lines of the patch below, if you see any value in > > it. (not tested, probably not quite right). > > Oh ok, because SIOC{S,G}IFBR compat ioctl was painfully done with > old_bridge_ioctl() I didn't think those needed compat. So I adapted and > fixed your patch to get that working.Ok, thanks!> Here is my test results. > > With my initial patch only : > - 64bit busybox's brctl (working) > # brctl show > bridge name bridge id STP enabled interfaces > br0 8000.000000000000 n > > - CONFIG_COMPAT=y + 32bit busybox's brctl (not working) > # brctl show > brctl: SIOCGIFBR: Invalid argument > > With both my intial patch and the one below : > - 64bit busybox's brctl (working) > # brctl show > bridge name bridge id STP enabled interfaces > br0 8000.000000000000 n > > - CONFIG_COMPAT=y + 32bit busybox's brctl (working) > # brctl show > bridge name bridge id STP enabled interfaces > br0 8000.000000000000 n > > If you think this has enough value to fix those compatility issues I can > either send the below patch as a V2 replacing my initial one for net > or sending it as a separate patch for net-next. What would you rather > like ?If 32-bit busybox still uses those ioctls in moderately recent versions, then it's probably worth doing this, but that would be up to the bridge maintainers. Your patch looks good to me, I see you caught a few mistakes in my prototype. I would however suggest basing it on top of your original fix, so that can be applied first and backported to stable kernels, while the new patch would go on top and not get backported. If that works with everyone, please submit those two, and add these tags to the second patch: Co-developed-by: Arnd Bergmann <arnd at arndb.de> Signed-off-by: Arnd Bergmann <arnd at arndb.de>