userns: Teach security_path_chown to take kuids and kgids

Don't make the security modules deal with raw user space uid and
gids instead pass in a kuid_t and a kgid_t so that security modules
only have to deal with internal kernel uids and gids.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: James Morris <james.l.morris@oracle.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

fs/open.c

@@ -534,7 +534,7 @@ static int chown_common(struct path *path, uid_t user, gid_t group)
 		newattrs.ia_valid |=
 			ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 	mutex_lock(&inode->i_mutex);
-	error = security_path_chown(path, user, group);
+	error = security_path_chown(path, uid, gid);
 	if (!error)
 		error = notify_change(path->dentry, &newattrs);
 	mutex_unlock(&inode->i_mutex);

include/linux/security.h

@@ -1437,7 +1437,7 @@ struct security_operations {
 	int (*path_rename) (struct path *old_dir, struct dentry *old_dentry,
 			    struct path *new_dir, struct dentry *new_dentry);
 	int (*path_chmod) (struct path *path, umode_t mode);
-	int (*path_chown) (struct path *path, uid_t uid, gid_t gid);
+	int (*path_chown) (struct path *path, kuid_t uid, kgid_t gid);
 	int (*path_chroot) (struct path *path);
 #endif
 
@@ -2832,7 +2832,7 @@ int security_path_link(struct dentry *old_dentry, struct path *new_dir,
 int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
 			 struct path *new_dir, struct dentry *new_dentry);
 int security_path_chmod(struct path *path, umode_t mode);
-int security_path_chown(struct path *path, uid_t uid, gid_t gid);
+int security_path_chown(struct path *path, kuid_t uid, kgid_t gid);
 int security_path_chroot(struct path *path);
 #else	/* CONFIG_SECURITY_PATH */
 static inline int security_path_unlink(struct path *dir, struct dentry *dentry)
@@ -2888,7 +2888,7 @@ static inline int security_path_chmod(struct path *path, umode_t mode)
 	return 0;
 }
 
-static inline int security_path_chown(struct path *path, uid_t uid, gid_t gid)
+static inline int security_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 {
 	return 0;
 }

security/apparmor/lsm.c

@@ -352,7 +352,7 @@ static int apparmor_path_chmod(struct path *path, umode_t mode)
 	return common_perm_mnt_dentry(OP_CHMOD, path->mnt, path->dentry, AA_MAY_CHMOD);
 }
 
-static int apparmor_path_chown(struct path *path, uid_t uid, gid_t gid)
+static int apparmor_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 {
 	struct path_cond cond =  { path->dentry->d_inode->i_uid,
 				   path->dentry->d_inode->i_mode

security/capability.c

@@ -284,7 +284,7 @@ static int cap_path_chmod(struct path *path, umode_t mode)
 	return 0;
 }
 
-static int cap_path_chown(struct path *path, uid_t uid, gid_t gid)
+static int cap_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 {
 	return 0;
 }

security/security.c

@@ -434,7 +434,7 @@ int security_path_chmod(struct path *path, umode_t mode)
 	return security_ops->path_chmod(path, mode);
 }
 
-int security_path_chown(struct path *path, uid_t uid, gid_t gid)
+int security_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 {
 	if (unlikely(IS_PRIVATE(path->dentry->d_inode)))
 		return 0;

security/tomoyo/tomoyo.c

@@ -373,13 +373,15 @@ static int tomoyo_path_chmod(struct path *path, umode_t mode)
  *
  * Returns 0 on success, negative value otherwise.
  */
-static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
+static int tomoyo_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 {
 	int error = 0;
-	if (uid != (uid_t) -1)
-		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path, uid);
-	if (!error && gid != (gid_t) -1)
-		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path, gid);
+	if (uid_valid(uid))
+		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path,
+						from_kuid(&init_user_ns, uid));
+	if (!error && gid_valid(gid))
+		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path,
+						from_kgid(&init_user_ns, gid));
 	return error;
 }