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;
+}