TOMOYO: Add mount restriction.
mount(2) has three string and one numeric parameters.
Split mount restriction code from security/tomoyo/file.c .
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c
new file mode 100644
index 0000000..507be09
--- /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;
+}