From 50857e2a59d8beddc6bb76137df026d67f30d5ca Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 6 Nov 2009 22:52:32 -0800 Subject: net/tun: handle compat_ioctl directly The tun driver is the only code in the kernel that operates on a character device with struct ifreq. Change the driver to handle the conversion itself so we can contain the remaining ifreq handling in the socket layer. This also fixes a bug in the handling of invalid ioctl numbers on an unbound tun device. The driver treats this as a TUNSETIFF in native mode, but there is no way for the generic compat_ioctl() function to emulate this behaviour. Possibly the driver was only doing this accidentally anyway, but if any code relies on this misfeature, it now also works in compat mode. Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller --- drivers/net/tun.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 46 insertions(+), 7 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 9c59a82784d..01e99f22210 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -53,6 +53,7 @@ #include #include #include +#include #include #include #include @@ -1109,8 +1110,8 @@ static int set_offload(struct net_device *dev, unsigned long arg) return 0; } -static long tun_chr_ioctl(struct file *file, unsigned int cmd, - unsigned long arg) +static long __tun_chr_ioctl(struct file *file, unsigned int cmd, + unsigned long arg, int ifreq_len) { struct tun_file *tfile = file->private_data; struct tun_struct *tun; @@ -1120,7 +1121,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd, int ret; if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) - if (copy_from_user(&ifr, argp, sizeof ifr)) + if (copy_from_user(&ifr, argp, ifreq_len)) return -EFAULT; if (cmd == TUNGETFEATURES) { @@ -1143,7 +1144,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd, if (ret) goto unlock; - if (copy_to_user(argp, &ifr, sizeof(ifr))) + if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; goto unlock; } @@ -1161,7 +1162,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd, if (ret) break; - if (copy_to_user(argp, &ifr, sizeof(ifr))) + if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; break; @@ -1235,7 +1236,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd, /* Get hw addres */ memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); ifr.ifr_hwaddr.sa_family = tun->dev->type; - if (copy_to_user(argp, &ifr, sizeof ifr)) + if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; break; @@ -1274,6 +1275,41 @@ unlock: return ret; } +static long tun_chr_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); +} + +#ifdef CONFIG_COMPAT +static long tun_chr_compat_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case TUNSETIFF: + case TUNGETIFF: + case TUNSETTXFILTER: + case TUNGETSNDBUF: + case TUNSETSNDBUF: + case SIOCGIFHWADDR: + case SIOCSIFHWADDR: + arg = (unsigned long)compat_ptr(arg); + break; + default: + arg = (compat_ulong_t)arg; + break; + } + + /* + * compat_ifreq is shorter than ifreq, so we must not access beyond + * the end of that structure. All fields that are used in this + * driver are compatible though, we don't need to convert the + * contents. + */ + return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); +} +#endif /* CONFIG_COMPAT */ + static int tun_chr_fasync(int fd, struct file *file, int on) { struct tun_struct *tun = tun_get(file); @@ -1356,7 +1392,10 @@ static const struct file_operations tun_fops = { .write = do_sync_write, .aio_write = tun_chr_aio_write, .poll = tun_chr_poll, - .unlocked_ioctl = tun_chr_ioctl, + .unlocked_ioctl = tun_chr_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = tun_chr_compat_ioctl, +#endif .open = tun_chr_open, .release = tun_chr_close, .fasync = tun_chr_fasync -- cgit v1.2.3