Patch "tmpfs: clear S_ISGID when setting posix ACLs" has been added to the 4.9-stable tree

Patch "tmpfs: clear S_ISGID when setting posix ACLs" has been added to the 4.9-stable tree

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From 497de07d89c1410d76a15bec2bb41f24a2a89f31 Mon Sep 17 00:00:00 2001
From: Gu Zheng <guzheng1@huawei.com>
Date: Mon, 9 Jan 2017 09:34:48 +0800
Subject: tmpfs: clear S_ISGID when setting posix ACLs

From: Gu Zheng <guzheng1@huawei.com>

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

Signed-off-by: Gu Zheng <guzheng1@huawei.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -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 guzheng1@huawei.com are

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