Patch "xfs: Don't clear SGID when inheriting ACLs" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

xfs: Don't clear SGID when inheriting ACLs

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xfs-don-t-clear-sgid-when-inheriting-acls.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jan Kara <[email protected]>
Date: Mon, 26 Jun 2017 08:48:18 -0700
Subject: xfs: Don't clear SGID when inheriting ACLs

From: Jan Kara <[email protected]>

commit 8ba358756aa08414fa9e65a1a41d28304ed6fd7f upstream.

When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit set, DIR1 is expected to have SGID bit set (and owning group equal to the owning group of 'DIR0'). However when 'DIR0' also has some default ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on 'DIR1' to get cleared if user is not member of the owning group.

Fix the problem by calling __xfs_set_acl() instead of xfs_set_acl() when setting up inode in xfs_generic_create(). That prevents SGID bit clearing and mode is properly set by posix_acl_create() anyway. We also reorder arguments of __xfs_set_acl() to match the ordering of xfs_set_acl() to make things consistent.

---
 fs/xfs/xfs_acl.c  |    6 +++---
 fs/xfs/xfs_acl.h  |    1 +
 fs/xfs/xfs_iops.c |    4 ++--
 3 files changed, 6 insertions(+), 5 deletions(-)

@@ -170,8 +170,8 @@ xfs_get_acl(struct inode *inode, int typ
 	return acl;
 }
 
-STATIC int
-__xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
+int
+__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
 	struct xfs_inode *ip = XFS_I(inode);
 	unsigned char *ea_name;

@@ -268,5 +268,5 @@ xfs_set_acl(struct inode *inode, struct
 	}
 
  set_acl:
-	return __xfs_set_acl(inode, type, acl);
+	return __xfs_set_acl(inode, acl, type);
 }

@@ -24,6 +24,7 @@ struct posix_acl;
 #ifdef CONFIG_XFS_POSIX_ACL
 extern struct posix_acl *xfs_get_acl(struct inode *inode, int type);
 extern int xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+extern int __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 #else
 static inline struct posix_acl *xfs_get_acl(struct inode *inode, int type)
 {

@@ -190,12 +190,12 @@ xfs_generic_create(
 
 #ifdef CONFIG_XFS_POSIX_ACL
 	if (default_acl) {
-		error = xfs_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
+		error = __xfs_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
 		if (error)
 			goto out_cleanup_inode;
 	}
 	if (acl) {
-		error = xfs_set_acl(inode, acl, ACL_TYPE_ACCESS);
+		error = __xfs_set_acl(inode, acl, ACL_TYPE_ACCESS);
 		if (error)
 			goto out_cleanup_inode;
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/f2fs-don-t-clear-sgid-when-inheriting-acls.patch queue-4.9/ext2-don-t-clear-sgid-when-inheriting-acls.patch queue-4.9/btrfs-don-t-clear-sgid-when-inheriting-acls.patch queue-4.9/xfs-don-t-clear-sgid-when-inheriting-acls.patch