Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 237 insertions, 0 deletions

diff --git a/security/tomoyo/mount.c b/security/tomoyo/mount.c
new file mode 100644
index 000000000..807fd91db
--- /dev/null
+++ b/security/tomoyo/mount.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * security/tomoyo/mount.c
+ *
+ * Copyright (C) 2005-2011  NTT DATA CORPORATION
+ */
+
+#include <linux/slab.h>
+#include "common.h"
+
+/* String table for special mount operations. */
+static const char * const tomoyo_mounts[TOMOYO_MAX_SPECIAL_MOUNT] = {
+	[TOMOYO_MOUNT_BIND]            = "--bind",
+	[TOMOYO_MOUNT_MOVE]            = "--move",
+	[TOMOYO_MOUNT_REMOUNT]         = "--remount",
+	[TOMOYO_MOUNT_MAKE_UNBINDABLE] = "--make-unbindable",
+	[TOMOYO_MOUNT_MAKE_PRIVATE]    = "--make-private",
+	[TOMOYO_MOUNT_MAKE_SLAVE]      = "--make-slave",
+	[TOMOYO_MOUNT_MAKE_SHARED]     = "--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)
+{
+	return tomoyo_supervisor(r, "file mount %s %s %s 0x%lX\n",
+				 r->param.mount.dev->name,
+				 r->param.mount.dir->name,
+				 r->param.mount.type->name,
+				 r->param.mount.flags);
+}
+
+/**
+ * tomoyo_check_mount_acl - Check permission for path path path number operation.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @ptr: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if granted, false otherwise.
+ */
+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. Maybe NULL.
+ * @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,
+			    const char *dev_name,
+			    const struct path *dir, const char *type,
+			    unsigned long flags)
+{
+	struct tomoyo_obj_info obj = { };
+	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;
+	r->obj = &obj;
+
+	/* Get fstype. */
+	requested_type = tomoyo_encode(type);
+	if (!requested_type)
+		goto out;
+	rtype.name = requested_type;
+	tomoyo_fill_path_info(&rtype);
+
+	/* Get mount point. */
+	obj.path2 = *dir;
+	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 (type == tomoyo_mounts[TOMOYO_MOUNT_REMOUNT]) {
+		/* dev_name is ignored. */
+	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE] ||
+		   type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE] ||
+		   type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE] ||
+		   type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED]) {
+		/* dev_name is ignored. */
+	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_BIND] ||
+		   type == tomoyo_mounts[TOMOYO_MOUNT_MOVE]) {
+		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 (!dev_name || kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
+			error = -ENOENT;
+			goto out;
+		}
+		obj.path1 = path;
+		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);
+	/* Drop refcount obtained by kern_path(). */
+	if (obj.path1.dentry)
+		path_put(&obj.path1);
+	return error;
+}
+
+/**
+ * tomoyo_mount_permission - Check permission for mount() operation.
+ *
+ * @dev_name:  Name of device file. Maybe NULL.
+ * @path:      Pointer to "struct path".
+ * @type:      Name of filesystem type. Maybe NULL.
+ * @flags:     Mount options.
+ * @data_page: Optional data. Maybe NULL.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_mount_permission(const char *dev_name, const struct path *path,
+			    const 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_mounts[TOMOYO_MOUNT_REMOUNT];
+		flags &= ~MS_REMOUNT;
+	} else if (flags & MS_BIND) {
+		type = tomoyo_mounts[TOMOYO_MOUNT_BIND];
+		flags &= ~MS_BIND;
+	} else if (flags & MS_SHARED) {
+		if (flags & (MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+			return -EINVAL;
+		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED];
+		flags &= ~MS_SHARED;
+	} else if (flags & MS_PRIVATE) {
+		if (flags & (MS_SHARED | MS_SLAVE | MS_UNBINDABLE))
+			return -EINVAL;
+		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE];
+		flags &= ~MS_PRIVATE;
+	} else if (flags & MS_SLAVE) {
+		if (flags & (MS_SHARED | MS_PRIVATE | MS_UNBINDABLE))
+			return -EINVAL;
+		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE];
+		flags &= ~MS_SLAVE;
+	} else if (flags & MS_UNBINDABLE) {
+		if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE))
+			return -EINVAL;
+		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE];
+		flags &= ~MS_UNBINDABLE;
+	} else if (flags & MS_MOVE) {
+		type = tomoyo_mounts[TOMOYO_MOUNT_MOVE];
+		flags &= ~MS_MOVE;
+	}
+	if (!type)
+		type = "<NULL>";
+	idx = tomoyo_read_lock();
+	error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
+	tomoyo_read_unlock(idx);
+	return error;
+}