Patch "jfs: 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

jfs: 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:
jfs-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: Thu, 22 Jun 2017 15:31:10 +0200
Subject: jfs: Don't clear SGID when inheriting ACLs

From: Jan Kara <[email protected]>

commit 9bcf66c72d726322441ec82962994e69157613e4 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 moving posix_acl_update_mode() out of __jfs_set_acl() into jfs_set_acl(). That way the function will not be called when inheriting ACLs which is what we want as it prevents SGID bit clearing and the mode has been properly set by posix_acl_create() anyway.

---
 fs/jfs/acl.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

@@ -77,13 +77,6 @@ static int __jfs_set_acl(tid_t tid, stru
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		ea_name = XATTR_NAME_POSIX_ACL_ACCESS;
-		if (acl) {
-			rc = posix_acl_update_mode(inode, &inode->i_mode, &acl);
-			if (rc)
-				return rc;
-			inode->i_ctime = current_time(inode);
-			mark_inode_dirty(inode);
-		}
 		break;
 	case ACL_TYPE_DEFAULT:
 		ea_name = XATTR_NAME_POSIX_ACL_DEFAULT;

@@ -118,9 +111,17 @@ int jfs_set_acl(struct inode *inode, str
 
 	tid = txBegin(inode->i_sb, 0);
 	mutex_lock(&JFS_IP(inode)->commit_mutex);
+	if (type == ACL_TYPE_ACCESS && acl) {
+		rc = posix_acl_update_mode(inode, &inode->i_mode, &acl);
+		if (rc)
+			goto end_tx;
+		inode->i_ctime = current_time(inode);
+		mark_inode_dirty(inode);
+	}
 	rc = __jfs_set_acl(tid, inode, type, acl);
 	if (!rc)
 		rc = txCommit(tid, 1, &inode, 0);
+end_tx:
 	txEnd(tid);
 	mutex_unlock(&JFS_IP(inode)->commit_mutex);
 	return rc;

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

queue-4.9/jfs-don-t-clear-sgid-when-inheriting-acls.patch