1 files changed, 58 insertions, 23 deletions

diff --git a/kernel/fs/posix_acl.c b/kernel/fs/posix_acl.c
index 4adde1e2c..993bb3b5f 100644
--- a/kernel/fs/posix_acl.c
+++ b/kernel/fs/posix_acl.c
@@ -592,6 +592,37 @@ no_mem:
 }
 EXPORT_SYMBOL_GPL(posix_acl_create);
 
+/**
+ * posix_acl_update_mode  -  update mode in set_acl
+ *
+ * Update the file mode when setting an ACL: compute the new file permission
+ * bits based on the ACL.  In addition, if the ACL is equivalent to the new
+ * file mode, set *acl to NULL to indicate that no ACL should be set.
+ *
+ * As with chmod, clear the setgit bit if the caller is not in the owning group
+ * or capable of CAP_FSETID (see inode_change_ok).
+ *
+ * Called from set_acl inode operations.
+ */
+int posix_acl_update_mode(struct inode *inode, umode_t *mode_p,
+			  struct posix_acl **acl)
+{
+	umode_t mode = inode->i_mode;
+	int error;
+
+	error = posix_acl_equiv_mode(*acl, &mode);
+	if (error < 0)
+		return error;
+	if (error == 0)
+		*acl = NULL;
+	if (!in_group_p(inode->i_gid) &&
+	    !capable_wrt_inode_uidgid(inode, CAP_FSETID))
+		mode &= ~S_ISGID;
+	*mode_p = mode;
+	return 0;
+}
+EXPORT_SYMBOL(posix_acl_update_mode);
+
 /*
  * Fix up the uids and gids in posix acl extended attributes in place.
  */
@@ -788,6 +819,28 @@ posix_acl_xattr_get(const struct xattr_handler *handler,
 	return error;
 }
 
+int
+set_posix_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+	if (!IS_POSIXACL(inode))
+		return -EOPNOTSUPP;
+	if (!inode->i_op->set_acl)
+		return -EOPNOTSUPP;
+
+	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
+		return acl ? -EACCES : 0;
+	if (!inode_owner_or_capable(inode))
+		return -EPERM;
+
+	if (acl) {
+		int ret = posix_acl_valid(acl);
+		if (ret)
+			return ret;
+	}
+	return inode->i_op->set_acl(inode, acl, type);
+}
+EXPORT_SYMBOL(set_posix_acl);
+
 static int
 posix_acl_xattr_set(const struct xattr_handler *handler,
 		    struct dentry *dentry, const char *name,
@@ -799,30 +852,13 @@ posix_acl_xattr_set(const struct xattr_handler *handler,
 
 	if (strcmp(name, "") != 0)
 		return -EINVAL;
-	if (!IS_POSIXACL(inode))
-		return -EOPNOTSUPP;
-	if (!inode->i_op->set_acl)
-		return -EOPNOTSUPP;
-
-	if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
-		return value ? -EACCES : 0;
-	if (!inode_owner_or_capable(inode))
-		return -EPERM;
 
 	if (value) {
 		acl = posix_acl_from_xattr(&init_user_ns, value, size);
 		if (IS_ERR(acl))
 			return PTR_ERR(acl);
-
-		if (acl) {
-			ret = posix_acl_valid(acl);
-			if (ret)
-				goto out;
-		}
 	}
-
-	ret = inode->i_op->set_acl(inode, acl, handler->flags);
-out:
+	ret = set_posix_acl(inode, handler->flags, acl);
 	posix_acl_release(acl);
 	return ret;
 }
@@ -867,11 +903,10 @@ int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	int error;
 
 	if (type == ACL_TYPE_ACCESS) {
-		error = posix_acl_equiv_mode(acl, &inode->i_mode);
-		if (error < 0)
-			return 0;
-		if (error == 0)
-			acl = NULL;
+		error = posix_acl_update_mode(inode,
+				&inode->i_mode, &acl);
+		if (error)
+			return error;
 	}
 
 	inode->i_ctime = CURRENT_TIME;