(namespace) Revert "UBUNTU: SAUCE: fs: Update posix_acl support to handle user namespace mounts"

BugLink: http://bugs.launchpad.net/bugs/1634964

This reverts commit 7efdc167 in
order to apply the corresponding upstream patch.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

fs/posix_acl.c

@@ -626,77 +626,59 @@ EXPORT_SYMBOL(posix_acl_update_mode);
 /*
  * Fix up the uids and gids in posix acl extended attributes in place.
  */
-static int posix_acl_fix_xattr_userns(
+static void posix_acl_fix_xattr_userns(
 	struct user_namespace *to, struct user_namespace *from,
 	void *value, size_t size)
 {
 	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
 	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
 	int count;
-	kuid_t kuid;
-	uid_t uid;
-	kgid_t kgid;
-	gid_t gid;
+	kuid_t uid;
+	kgid_t gid;
 
 	if (!value)
-		return 0;
+		return;
 	if (size < sizeof(posix_acl_xattr_header))
-		return 0;
+		return;
 	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
-		return 0;
+		return;
 
 	count = posix_acl_xattr_count(size);
 	if (count < 0)
-		return 0;
+		return;
 	if (count == 0)
-		return 0;
+		return;
 
 	for (end = entry + count; entry != end; entry++) {
 		switch(le16_to_cpu(entry->e_tag)) {
 		case ACL_USER:
-			kuid = make_kuid(from, le32_to_cpu(entry->e_id));
-			if (!uid_valid(kuid))
-				return -EOVERFLOW;
-			uid = from_kuid(to, kuid);
-			if (uid == (uid_t)-1)
-				return -EOVERFLOW;
-			entry->e_id = cpu_to_le32(uid);
+			uid = make_kuid(from, le32_to_cpu(entry->e_id));
+			entry->e_id = cpu_to_le32(from_kuid(to, uid));
 			break;
 		case ACL_GROUP:
-			kgid = make_kgid(from, le32_to_cpu(entry->e_id));
-			if (!gid_valid(kgid))
-				return -EOVERFLOW;
-			gid = from_kgid(to, kgid);
-			if (gid == (gid_t)-1)
-				return -EOVERFLOW;
-			entry->e_id = cpu_to_le32(gid);
+			gid = make_kgid(from, le32_to_cpu(entry->e_id));
+			entry->e_id = cpu_to_le32(from_kgid(to, gid));
 			break;
 		default:
 			break;
 		}
 	}
-
-	return 0;
 }
 
-int
-posix_acl_fix_xattr_from_user(struct user_namespace *target_ns, void *value,
-			      size_t size)
+void posix_acl_fix_xattr_from_user(void *value, size_t size)
 {
-	struct user_namespace *source_ns = current_user_ns();
-	if (source_ns == target_ns)
-		return 0;
-	return posix_acl_fix_xattr_userns(target_ns, source_ns, value, size);
+	struct user_namespace *user_ns = current_user_ns();
+	if (user_ns == &init_user_ns)
+		return;
+	posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
 }
 
-int
-posix_acl_fix_xattr_to_user(struct user_namespace *source_ns, void *value,
-			    size_t size)
+void posix_acl_fix_xattr_to_user(void *value, size_t size)
 {
-	struct user_namespace *target_ns = current_user_ns();
-	if (target_ns == source_ns)
-		return 0;
-	return posix_acl_fix_xattr_userns(target_ns, source_ns, value, size);
+	struct user_namespace *user_ns = current_user_ns();
+	if (user_ns == &init_user_ns)
+		return;
+	posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
 }
 
 /*
@@ -831,7 +813,7 @@ posix_acl_xattr_get(const struct xattr_handler *handler,
 	if (acl == NULL)
 		return -ENODATA;
 
-	error = posix_acl_to_xattr(dentry->d_sb->s_user_ns, acl, value, size);
+	error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
 	posix_acl_release(acl);
 
 	return error;
@@ -872,8 +854,7 @@ posix_acl_xattr_set(const struct xattr_handler *handler,
 		return -EINVAL;
 
 	if (value) {
-		acl = posix_acl_from_xattr(dentry->d_sb->s_user_ns, value,
-					   size);
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
 		if (IS_ERR(acl))
 			return PTR_ERR(acl);
 	}

fs/xattr.c

@@ -352,12 +352,8 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
 			goto out;
 		}
 		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) {
-			error = posix_acl_fix_xattr_from_user(d->d_sb->s_user_ns,
-							      kvalue, size);
-			if (error)
-				goto out;
-		}
+		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
+			posix_acl_fix_xattr_from_user(kvalue, size);
 	}
 
 	error = vfs_setxattr(d, kname, kvalue, size, flags);
@@ -457,14 +453,9 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
 	error = vfs_getxattr(d, kname, kvalue, size);
 	if (error > 0) {
 		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) {
-			int ret;
-			ret = posix_acl_fix_xattr_to_user(d->d_sb->s_user_ns,
-							  kvalue, size);
-			if (ret)
-				error = ret;
-		}
-		if (error > 0 && size && copy_to_user(value, kvalue, error))
+		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
+			posix_acl_fix_xattr_to_user(kvalue, size);
+		if (size && copy_to_user(value, kvalue, error))
 			error = -EFAULT;
 	} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
 		/* The file system tried to returned a value bigger

include/linux/posix_acl_xattr.h

@@ -53,23 +53,14 @@ posix_acl_xattr_count(size_t size)
 }
 
 #ifdef CONFIG_FS_POSIX_ACL
-int posix_acl_fix_xattr_from_user(struct user_namespace *target_ns,
-				  void *value, size_t size);
-int posix_acl_fix_xattr_to_user(struct user_namespace *source_ns, void *value,
-				size_t size);
+void posix_acl_fix_xattr_from_user(void *value, size_t size);
+void posix_acl_fix_xattr_to_user(void *value, size_t size);
 #else
-static inline int
-posix_acl_fix_xattr_from_user(struct user_namespace *target_ns, void *value,
-			      size_t size)
+static inline void posix_acl_fix_xattr_from_user(void *value, size_t size)
 {
-	return 0;
 }
-
-static inline int
-posix_acl_fix_xattr_to_user(struct user_namespace *source_ns, void *value,
-			    size_t size)
+static inline void posix_acl_fix_xattr_to_user(void *value, size_t size)
 {
-	return 0;
 }
 #endif