Patch "tmpfs: clear S_ISGID when setting posix 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

tmpfs: clear S_ISGID when setting posix 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:
tmpfs-clear-s_isgid-when-setting-posix-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: Gu Zheng <[email protected]>
Date: Mon, 9 Jan 2017 09:34:48 +0800
Subject: tmpfs: clear S_ISGID when setting posix ACLs

From: Gu Zheng <[email protected]>

commit 497de07d89c1410d76a15bec2bb41f24a2a89f31 upstream.

This change was missed the tmpfs modification in In CVE-2016-7097 commit 073931017b49 ("posix_acl: Clear SGID bit when setting file permissions")
It can test by xfstest generic/375, which failed to clear setgid bit in the following test case on tmpfs:

touch $testfile
chown 100:100 $testfile
chmod 2755 $testfile
_runas -u 100 -g 101 -- setfacl -m u::rwx,g::rwx,o::rwx $testfile

---
 fs/posix_acl.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

@@ -922,11 +922,10 @@ int simple_set_acl(struct inode *inode,
 	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(inode);

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

queue-4.9/tmpfs-clear-s_isgid-when-setting-posix-acls.patch