diff options
| -rw-r--r-- | drivers/md/dm-ioctl.c | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 6aeae095086d..2afd2d2a0f40 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1811,30 +1811,36 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags) * As well as checking the version compatibility this always * copies the kernel interface version out. */ -static int check_version(unsigned int cmd, struct dm_ioctl __user *user) +static int check_version(unsigned int cmd, struct dm_ioctl __user *user, + struct dm_ioctl *kernel_params) { - uint32_t version[3]; int r = 0; - if (copy_from_user(version, user->version, sizeof(version))) + /* Make certain version is first member of dm_ioctl struct */ + BUILD_BUG_ON(offsetof(struct dm_ioctl, version) != 0); + + if (copy_from_user(kernel_params->version, user->version, sizeof(kernel_params->version))) return -EFAULT; - if ((version[0] != DM_VERSION_MAJOR) || - (version[1] > DM_VERSION_MINOR)) { + if ((kernel_params->version[0] != DM_VERSION_MAJOR) || + (kernel_params->version[1] > DM_VERSION_MINOR)) { DMERR("ioctl interface mismatch: kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)", DM_VERSION_MAJOR, DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, - version[0], version[1], version[2], cmd); + kernel_params->version[0], + kernel_params->version[1], + kernel_params->version[2], + cmd); r = -EINVAL; } /* * Fill in the kernel version. */ - version[0] = DM_VERSION_MAJOR; - version[1] = DM_VERSION_MINOR; - version[2] = DM_VERSION_PATCHLEVEL; - if (copy_to_user(user->version, version, sizeof(version))) + kernel_params->version[0] = DM_VERSION_MAJOR; + kernel_params->version[1] = DM_VERSION_MINOR; + kernel_params->version[2] = DM_VERSION_PATCHLEVEL; + if (copy_to_user(user->version, kernel_params->version, sizeof(kernel_params->version))) return -EFAULT; return r; @@ -1860,7 +1866,10 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern const size_t minimum_data_size = offsetof(struct dm_ioctl, data); unsigned int noio_flag; - if (copy_from_user(param_kernel, user, minimum_data_size)) + /* check_version() already copied version from userspace, avoid TOCTOU */ + if (copy_from_user((char *)param_kernel + sizeof(param_kernel->version), + (char __user *)user + sizeof(param_kernel->version), + minimum_data_size - sizeof(param_kernel->version))) return -EFAULT; if (param_kernel->data_size < minimum_data_size) { @@ -1972,7 +1981,7 @@ static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *us * Check the interface version passed in. This also * writes out the kernel's interface version. */ - r = check_version(cmd, user); + r = check_version(cmd, user, ¶m_kernel); if (r) return r; |