@@ -49,7 +49,7 @@ obj-$(CONFIG_SYSCTL) += drop_caches.o
obj-$(CONFIG_FHANDLE) += fhandle.o
obj-$(CONFIG_FS_RICHACL) += richacl.o
-richacl-y := richacl_base.o
+richacl-y := richacl_base.o richacl_inode.o
obj-y += quota/
new file mode 100644
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2010 Novell, Inc.
+ * Copyright (C) 2015 Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruenba@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/richacl.h>
+
+/**
+ * richacl_permission - richacl permission check algorithm
+ * @inode: inode to check
+ * @acl: rich acl of the inode
+ * @want: requested access (MAY_* flags)
+ *
+ * Checks if the current process is granted @mask flags in @acl.
+ */
+int
+richacl_permission(struct inode *inode, const struct richacl *acl,
+ int want)
+{
+ const struct richace *ace;
+ unsigned int mask = richacl_want_to_mask(want);
+ unsigned int requested = mask, denied = 0;
+ int in_owning_group = in_group_p(inode->i_gid);
+ int in_owner_or_group_class = in_owning_group;
+
+ /*
+ * A process is
+ * - in the owner file class if it owns the file,
+ * - in the group file class if it is in the file's owning group or
+ * it matches any of the user or group entries, and
+ * - in the other file class otherwise.
+ * The file class is only relevant for determining which file mask to
+ * apply, which only happens for masked acls.
+ */
+ if (acl->a_flags & RICHACL_MASKED) {
+ if ((acl->a_flags & RICHACL_WRITE_THROUGH) &&
+ uid_eq(current_fsuid(), inode->i_uid)) {
+ denied = requested & ~acl->a_owner_mask;
+ goto out;
+ }
+ } else {
+ /*
+ * When the acl is not masked, there is no need to determine if
+ * the process is in the group class and we can break out
+ * earlier of the loop below.
+ */
+ in_owner_or_group_class = 1;
+ }
+
+ /*
+ * Check if the acl grants the requested access and determine which
+ * file class the process is in.
+ */
+ richacl_for_each_entry(ace, acl) {
+ unsigned int ace_mask = ace->e_mask;
+
+ if (richace_is_inherit_only(ace))
+ continue;
+ if (richace_is_owner(ace)) {
+ if (!uid_eq(current_fsuid(), inode->i_uid))
+ continue;
+ goto entry_matches_owner;
+ } else if (richace_is_group(ace)) {
+ if (!in_owning_group)
+ continue;
+ } else if (richace_is_unix_user(ace)) {
+ if (!uid_eq(current_fsuid(), ace->e_id.uid))
+ continue;
+ if (uid_eq(current_fsuid(), inode->i_uid))
+ goto entry_matches_owner;
+ } else if (richace_is_unix_group(ace)) {
+ if (!in_group_p(ace->e_id.gid))
+ continue;
+ } else
+ goto entry_matches_everyone;
+
+ /*
+ * Apply the group file mask to entries other than owner@ and
+ * everyone@ or user entries matching the owner. This ensures
+ * that we grant the same permissions as the acl computed by
+ * richacl_apply_masks().
+ *
+ * Without this restriction, the following richacl would grant
+ * rw access to processes which are both the owner and in the
+ * owning group, but not to other users in the owning group,
+ * which could not be represented without masks:
+ *
+ * owner:rw::mask
+ * group@:rw::allow
+ */
+ if ((acl->a_flags & RICHACL_MASKED) && richace_is_allow(ace))
+ ace_mask &= acl->a_group_mask;
+
+entry_matches_owner:
+ /* The process is in the owner or group file class. */
+ in_owner_or_group_class = 1;
+
+entry_matches_everyone:
+ /* Check which mask flags the ACE allows or denies. */
+ if (richace_is_deny(ace))
+ denied |= ace_mask & mask;
+ mask &= ~ace_mask;
+
+ /*
+ * Keep going until we know which file class
+ * the process is in.
+ */
+ if (!mask && in_owner_or_group_class)
+ break;
+ }
+ denied |= mask;
+
+ if (acl->a_flags & RICHACL_MASKED) {
+ /*
+ * The file class a process is in determines which file mask
+ * applies. Check if that file mask also grants the requested
+ * access.
+ */
+ if (uid_eq(current_fsuid(), inode->i_uid))
+ denied |= requested & ~acl->a_owner_mask;
+ else if (in_owner_or_group_class)
+ denied |= requested & ~acl->a_group_mask;
+ else {
+ if (acl->a_flags & RICHACL_WRITE_THROUGH)
+ denied = requested & ~acl->a_other_mask;
+ else
+ denied |= requested & ~acl->a_other_mask;
+ }
+ }
+
+out:
+ return denied ? -EACCES : 0;
+}
+EXPORT_SYMBOL_GPL(richacl_permission);
@@ -180,4 +180,7 @@ extern unsigned int richacl_mode_to_mask(umode_t);
extern unsigned int richacl_want_to_mask(unsigned int);
extern void richacl_compute_max_masks(struct richacl *);
+/* richacl_inode.c */
+extern int richacl_permission(struct inode *, const struct richacl *, int);
+
#endif /* __RICHACL_H */