diff options
Diffstat (limited to 'security/tomoyo/mount.c')
-rw-r--r-- | security/tomoyo/mount.c | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c new file mode 100644 index 00000000000..82bf8c2390b --- /dev/null +++ b/security/tomoyo/mount.c @@ -0,0 +1,284 @@ +/* + * 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_audit_mount_log - Audit mount log. + * + * @r: Pointer to "struct tomoyo_request_info". + * + * Returns 0 on success, negative value otherwise. + */ +static int tomoyo_audit_mount_log(struct tomoyo_request_info *r) +{ + const char *dev = r->param.mount.dev->name; + const char *dir = r->param.mount.dir->name; + const char *type = r->param.mount.type->name; + const unsigned long flags = r->param.mount.flags; + if (r->granted) + return 0; + if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD)) + tomoyo_warn_log(r, "mount -o remount %s 0x%lX", dir, flags); + else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD) + || !strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD)) + tomoyo_warn_log(r, "mount %s %s %s 0x%lX", type, dev, dir, + flags); + 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)) + tomoyo_warn_log(r, "mount %s %s 0x%lX", type, dir, flags); + else + tomoyo_warn_log(r, "mount -t %s %s %s 0x%lX", type, dev, dir, + flags); + return tomoyo_supervisor(r, + TOMOYO_KEYWORD_ALLOW_MOUNT "%s %s %s 0x%lX\n", + tomoyo_pattern(r->param.mount.dev), + tomoyo_pattern(r->param.mount.dir), type, + flags); +} + +static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r, + const struct tomoyo_acl_info *ptr) +{ + const struct tomoyo_mount_acl *acl = + container_of(ptr, typeof(*acl), head); + return tomoyo_compare_number_union(r->param.mount.flags, &acl->flags) && + tomoyo_compare_name_union(r->param.mount.type, &acl->fs_type) && + tomoyo_compare_name_union(r->param.mount.dir, &acl->dir_name) && + (!r->param.mount.need_dev || + tomoyo_compare_name_union(r->param.mount.dev, &acl->dev_name)); +} + +/** + * 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) +{ + struct path path; + 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_encode(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_encode(dev_name); + if (!requested_dev_name) { + error = -ENOMEM; + goto out; + } + } + rdev.name = requested_dev_name; + tomoyo_fill_path_info(&rdev); + r->param_type = TOMOYO_TYPE_MOUNT_ACL; + r->param.mount.need_dev = need_dev; + r->param.mount.dev = &rdev; + r->param.mount.dir = &rdir; + r->param.mount.type = &rtype; + r->param.mount.flags = flags; + do { + tomoyo_check_acl(r, tomoyo_check_mount_acl); + error = tomoyo_audit_mount_log(r); + } while (error == TOMOYO_RETRY_REQUEST); + out: + kfree(requested_dev_name); + kfree(requested_dir_name); + if (fstype) + put_filesystem(fstype); + kfree(requested_type); + 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_MAC_FILE_MOUNT) + == TOMOYO_CONFIG_DISABLED) + return 0; + if ((flags & MS_MGC_MSK) == MS_MGC_VAL) + flags &= ~MS_MGC_MSK; + if (flags & MS_REMOUNT) { + type = TOMOYO_MOUNT_REMOUNT_KEYWORD; + flags &= ~MS_REMOUNT; + } + if (flags & MS_MOVE) { + type = TOMOYO_MOUNT_MOVE_KEYWORD; + flags &= ~MS_MOVE; + } + if (flags & MS_BIND) { + type = TOMOYO_MOUNT_BIND_KEYWORD; + flags &= ~MS_BIND; + } + if (flags & MS_UNBINDABLE) { + type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD; + flags &= ~MS_UNBINDABLE; + } + if (flags & MS_PRIVATE) { + type = TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD; + flags &= ~MS_PRIVATE; + } + if (flags & MS_SLAVE) { + type = TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD; + flags &= ~MS_SLAVE; + } + if (flags & MS_SHARED) { + type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD; + flags &= ~MS_SHARED; + } + if (!type) + type = "<NULL>"; + idx = tomoyo_read_lock(); + error = tomoyo_mount_acl(&r, dev_name, path, type, flags); + tomoyo_read_unlock(idx); + return error; +} + +static bool tomoyo_same_mount_acl(const struct tomoyo_acl_info *a, + const struct tomoyo_acl_info *b) +{ + const struct tomoyo_mount_acl *p1 = container_of(a, typeof(*p1), head); + const struct tomoyo_mount_acl *p2 = container_of(b, typeof(*p2), head); + return tomoyo_same_acl_head(&p1->head, &p2->head) && + tomoyo_same_name_union(&p1->dev_name, &p2->dev_name) && + tomoyo_same_name_union(&p1->dir_name, &p2->dir_name) && + tomoyo_same_name_union(&p1->fs_type, &p2->fs_type) && + tomoyo_same_number_union(&p1->flags, &p2->flags); +} + +/** + * tomoyo_write_mount - 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. + * + * Caller holds tomoyo_read_lock(). + */ +int tomoyo_write_mount(char *data, struct tomoyo_domain_info *domain, + const bool is_delete) +{ + 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; + error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain, + tomoyo_same_mount_acl, NULL); + 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; +} |