diff options
Diffstat (limited to 'security/tomoyo/mount.c')
| -rw-r--r-- | security/tomoyo/mount.c | 366 |
1 files changed, 366 insertions, 0 deletions
diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c new file mode 100644 index 000000000000..507be09e93a9 --- /dev/null +++ b/security/tomoyo/mount.c @@ -0,0 +1,366 @@ +/* + * security/tomoyo/mount.c + * + * Copyright (C) 2005-2010 NTT DATA CORPORATION + */ + +#include <linux/slab.h> +#include "common.h" + +/* Keywords for mount restrictions. */ + +/* Allow to call 'mount --bind /source_dir /dest_dir' */ +#define TOMOYO_MOUNT_BIND_KEYWORD "--bind" +/* Allow to call 'mount --move /old_dir /new_dir ' */ +#define TOMOYO_MOUNT_MOVE_KEYWORD "--move" +/* Allow to call 'mount -o remount /dir ' */ +#define TOMOYO_MOUNT_REMOUNT_KEYWORD "--remount" +/* Allow to call 'mount --make-unbindable /dir' */ +#define TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD "--make-unbindable" +/* Allow to call 'mount --make-private /dir' */ +#define TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD "--make-private" +/* Allow to call 'mount --make-slave /dir' */ +#define TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD "--make-slave" +/* Allow to call 'mount --make-shared /dir' */ +#define TOMOYO_MOUNT_MAKE_SHARED_KEYWORD "--make-shared" + +/** + * tomoyo_encode2: Encode binary string to ascii string. + * + * @str: String in binary format. + * + * Returns pointer to @str in ascii format on success, NULL otherwise. + * + * This function uses kzalloc(), so caller must kfree() if this function + * didn't return NULL. + */ +static char *tomoyo_encode2(const char *str) +{ + int len = 0; + const char *p = str; + char *cp; + char *cp0; + if (!p) + return NULL; + while (*p) { + const unsigned char c = *p++; + if (c == '\\') + len += 2; + else if (c > ' ' && c < 127) + len++; + else + len += 4; + } + len++; + /* Reserve space for appending "/". */ + cp = kzalloc(len + 10, GFP_NOFS); + if (!cp) + return NULL; + cp0 = cp; + p = str; + while (*p) { + const unsigned char c = *p++; + if (c == '\\') { + *cp++ = '\\'; + *cp++ = '\\'; + } else if (c > ' ' && c < 127) { + *cp++ = c; + } else { + *cp++ = '\\'; + *cp++ = (c >> 6) + '0'; + *cp++ = ((c >> 3) & 7) + '0'; + *cp++ = (c & 7) + '0'; + } + } + return cp0; +} + +/** + * tomoyo_mount_acl2 - Check permission for mount() operation. + * + * @r: Pointer to "struct tomoyo_request_info". + * @dev_name: Name of device file. + * @dir: Pointer to "struct path". + * @type: Name of filesystem type. + * @flags: Mount options. + * + * Returns 0 on success, negative value otherwise. + * + * Caller holds tomoyo_read_lock(). + */ +static int tomoyo_mount_acl2(struct tomoyo_request_info *r, char *dev_name, + struct path *dir, char *type, unsigned long flags) +{ + struct path path; + struct tomoyo_acl_info *ptr; + struct file_system_type *fstype = NULL; + const char *requested_type = NULL; + const char *requested_dir_name = NULL; + const char *requested_dev_name = NULL; + struct tomoyo_path_info rtype; + struct tomoyo_path_info rdev; + struct tomoyo_path_info rdir; + int need_dev = 0; + int error = -ENOMEM; + + /* Get fstype. */ + requested_type = tomoyo_encode2(type); + if (!requested_type) + goto out; + rtype.name = requested_type; + tomoyo_fill_path_info(&rtype); + + /* Get mount point. */ + requested_dir_name = tomoyo_realpath_from_path(dir); + if (!requested_dir_name) { + error = -ENOMEM; + goto out; + } + rdir.name = requested_dir_name; + tomoyo_fill_path_info(&rdir); + + /* Compare fs name. */ + if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD)) { + /* dev_name is ignored. */ + } else if (!strcmp(type, TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD) || + !strcmp(type, TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD) || + !strcmp(type, TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD) || + !strcmp(type, TOMOYO_MOUNT_MAKE_SHARED_KEYWORD)) { + /* dev_name is ignored. */ + } else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD) || + !strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD)) { + need_dev = -1; /* dev_name is a directory */ + } else { + fstype = get_fs_type(type); + if (!fstype) { + error = -ENODEV; + goto out; + } + if (fstype->fs_flags & FS_REQUIRES_DEV) + /* dev_name is a block device file. */ + need_dev = 1; + } + if (need_dev) { + /* Get mount point or device file. */ + if (kern_path(dev_name, LOOKUP_FOLLOW, &path)) { + error = -ENOENT; + goto out; + } + requested_dev_name = tomoyo_realpath_from_path(&path); + if (!requested_dev_name) { + error = -ENOENT; + goto out; + } + } else { + /* Map dev_name to "<NULL>" if no dev_name given. */ + if (!dev_name) + dev_name = "<NULL>"; + requested_dev_name = tomoyo_encode2(dev_name); + if (!requested_dev_name) { + error = -ENOMEM; + goto out; + } + } + rdev.name = requested_dev_name; + tomoyo_fill_path_info(&rdev); + list_for_each_entry_rcu(ptr, &r->domain->acl_info_list, list) { + struct tomoyo_mount_acl *acl; + if (ptr->type != TOMOYO_TYPE_MOUNT_ACL) + continue; + acl = container_of(ptr, struct tomoyo_mount_acl, head); + if (acl->is_deleted || + !tomoyo_compare_number_union(flags, &acl->flags) || + !tomoyo_compare_name_union(&rtype, &acl->fs_type) || + !tomoyo_compare_name_union(&rdir, &acl->dir_name) || + (need_dev && + !tomoyo_compare_name_union(&rdev, &acl->dev_name))) + continue; + error = 0; + break; + } + if (error) { + const char *dev = tomoyo_get_file_pattern(&rdev)->name; + const char *dir = tomoyo_get_file_pattern(&rdir)->name; + int len = strlen(dev) + strlen(dir) + strlen(requested_type) + + 64; + char *buf = kzalloc(len, GFP_NOFS); + if (buf) { + snprintf(buf, len - 1, "%s %s %s 0x%lX", + dev, dir, requested_type, flags); + tomoyo_write_mount_policy(buf, r->domain, false); + kfree(buf); + } + } + out: + kfree(requested_dev_name); + kfree(requested_dir_name); + if (fstype) + put_filesystem(fstype); + kfree(requested_type); + return error; +} + +/** + * tomoyo_mount_acl - Check permission for mount() operation. + * + * @r: Pointer to "struct tomoyo_request_info". + * @dev_name: Name of device file. + * @dir: Pointer to "struct path". + * @type: Name of filesystem type. + * @flags: Mount options. + * + * Returns 0 on success, negative value otherwise. + * + * Caller holds tomoyo_read_lock(). + */ +static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name, + struct path *dir, char *type, unsigned long flags) +{ + int error; + error = -EPERM; + if ((flags & MS_MGC_MSK) == MS_MGC_VAL) + flags &= ~MS_MGC_MSK; + switch (flags & (MS_REMOUNT | MS_MOVE | MS_BIND)) { + case MS_REMOUNT: + case MS_MOVE: + case MS_BIND: + case 0: + break; + default: + printk(KERN_WARNING "ERROR: " + "%s%s%sare given for single mount operation.\n", + flags & MS_REMOUNT ? "'remount' " : "", + flags & MS_MOVE ? "'move' " : "", + flags & MS_BIND ? "'bind' " : ""); + return -EINVAL; + } + switch (flags & (MS_UNBINDABLE | MS_PRIVATE | MS_SLAVE | MS_SHARED)) { + case MS_UNBINDABLE: + case MS_PRIVATE: + case MS_SLAVE: + case MS_SHARED: + case 0: + break; + default: + printk(KERN_WARNING "ERROR: " + "%s%s%s%sare given for single mount operation.\n", + flags & MS_UNBINDABLE ? "'unbindable' " : "", + flags & MS_PRIVATE ? "'private' " : "", + flags & MS_SLAVE ? "'slave' " : "", + flags & MS_SHARED ? "'shared' " : ""); + return -EINVAL; + } + if (flags & MS_REMOUNT) + error = tomoyo_mount_acl(r, dev_name, dir, + TOMOYO_MOUNT_REMOUNT_KEYWORD, + flags & ~MS_REMOUNT); + else if (flags & MS_MOVE) + error = tomoyo_mount_acl(r, dev_name, dir, + TOMOYO_MOUNT_MOVE_KEYWORD, + flags & ~MS_MOVE); + else if (flags & MS_BIND) + error = tomoyo_mount_acl(r, dev_name, dir, + TOMOYO_MOUNT_BIND_KEYWORD, + flags & ~MS_BIND); + else if (flags & MS_UNBINDABLE) + error = tomoyo_mount_acl(r, dev_name, dir, + TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD, + flags & ~MS_UNBINDABLE); + else if (flags & MS_PRIVATE) + error = tomoyo_mount_acl(r, dev_name, dir, + TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD, + flags & ~MS_PRIVATE); + else if (flags & MS_SLAVE) + error = tomoyo_mount_acl(r, dev_name, dir, + TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD, + flags & ~MS_SLAVE); + else if (flags & MS_SHARED) + error = tomoyo_mount_acl(r, dev_name, dir, + TOMOYO_MOUNT_MAKE_SHARED_KEYWORD, + flags & ~MS_SHARED); + else + error = tomoyo_mount_acl2(r, dev_name, dir, type, flags); + if (r->mode != TOMOYO_CONFIG_ENFORCING) + error = 0; + return error; +} + +/** + * tomoyo_mount_permission - Check permission for mount() operation. + * + * @dev_name: Name of device file. + * @path: Pointer to "struct path". + * @type: Name of filesystem type. May be NULL. + * @flags: Mount options. + * @data_page: Optional data. May be NULL. + * + * Returns 0 on success, negative value otherwise. + */ +int tomoyo_mount_permission(char *dev_name, struct path *path, char *type, + unsigned long flags, void *data_page) +{ + struct tomoyo_request_info r; + int error; + int idx; + + if (tomoyo_init_request_info(&r, NULL) == TOMOYO_CONFIG_DISABLED) + return 0; + if (!type) + type = "<NULL>"; + idx = tomoyo_read_lock(); + error = tomoyo_mount_acl(&r, dev_name, path, type, flags); + tomoyo_read_unlock(idx); + return error; +} + +/** + * tomoyo_write_mount_policy - Write "struct tomoyo_mount_acl" list. + * + * @data: String to parse. + * @domain: Pointer to "struct tomoyo_domain_info". + * @is_delete: True if it is a delete request. + * + * Returns 0 on success, negative value otherwise. + */ +int tomoyo_write_mount_policy(char *data, struct tomoyo_domain_info *domain, + const bool is_delete) +{ + struct tomoyo_acl_info *ptr; + struct tomoyo_mount_acl e = { .head.type = TOMOYO_TYPE_MOUNT_ACL }; + int error = is_delete ? -ENOENT : -ENOMEM; + char *w[4]; + if (!tomoyo_tokenize(data, w, sizeof(w)) || !w[3][0]) + return -EINVAL; + if (!tomoyo_parse_name_union(w[0], &e.dev_name) || + !tomoyo_parse_name_union(w[1], &e.dir_name) || + !tomoyo_parse_name_union(w[2], &e.fs_type) || + !tomoyo_parse_number_union(w[3], &e.flags)) + goto out; + if (mutex_lock_interruptible(&tomoyo_policy_lock)) + goto out; + list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) { + struct tomoyo_mount_acl *acl = + container_of(ptr, struct tomoyo_mount_acl, head); + if (!tomoyo_is_same_mount_acl(acl, &e)) + continue; + acl->is_deleted = is_delete; + error = 0; + break; + } + if (!is_delete && error) { + struct tomoyo_mount_acl *entry = + tomoyo_commit_ok(&e, sizeof(e)); + if (entry) { + list_add_tail_rcu(&entry->head.list, + &domain->acl_info_list); + error = 0; + } + } + mutex_unlock(&tomoyo_policy_lock); + out: + tomoyo_put_name_union(&e.dev_name); + tomoyo_put_name_union(&e.dir_name); + tomoyo_put_name_union(&e.fs_type); + tomoyo_put_number_union(&e.flags); + return error; +} |
