Patch "ext4: Don't clear SGID when inheriting ACLs" has been added to the 4.12-stable tree

[<gregkh@linuxfoundation.org>]

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

    ext4: Don't clear SGID when inheriting ACLs

to the 4.12-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:
     ext4-don-t-clear-sgid-when-inheriting-acls.patch
and it can be found in the queue-4.12 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 a3bb2d5587521eea6dab2d05326abb0afb460abd Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Sun, 30 Jul 2017 23:33:01 -0400
Subject: ext4: Don't clear SGID when inheriting ACLs

From: Jan Kara <jack@suse.cz>

commit a3bb2d5587521eea6dab2d05326abb0afb460abd 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
__ext4_set_acl() into ext4_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.

Fixes: 073931017b49d9458aa351605b43a7e34598caef
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ext4/acl.c |   28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -189,18 +189,10 @@ __ext4_set_acl(handle_t *handle, struct
 	void *value = NULL;
 	size_t size = 0;
 	int error;
-	int update_mode = 0;
-	umode_t mode = inode->i_mode;
 
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
-		if (acl) {
-			error = posix_acl_update_mode(inode, &mode, &acl);
-			if (error)
-				return error;
-			update_mode = 1;
-		}
 		break;
 
 	case ACL_TYPE_DEFAULT:
@@ -224,11 +216,6 @@ __ext4_set_acl(handle_t *handle, struct
 	kfree(value);
 	if (!error) {
 		set_cached_acl(inode, type, acl);
-		if (update_mode) {
-			inode->i_mode = mode;
-			inode->i_ctime = current_time(inode);
-			ext4_mark_inode_dirty(handle, inode);
-		}
 	}
 
 	return error;
@@ -239,6 +226,8 @@ ext4_set_acl(struct inode *inode, struct
 {
 	handle_t *handle;
 	int error, retries = 0;
+	umode_t mode = inode->i_mode;
+	int update_mode = 0;
 
 	error = dquot_initialize(inode);
 	if (error)
@@ -249,7 +238,20 @@ retry:
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
+	if ((type == ACL_TYPE_ACCESS) && acl) {
+		error = posix_acl_update_mode(inode, &mode, &acl);
+		if (error)
+			goto out_stop;
+		update_mode = 1;
+	}
+
 	error = __ext4_set_acl(handle, inode, type, acl);
+	if (!error && update_mode) {
+		inode->i_mode = mode;
+		inode->i_ctime = current_time(inode);
+		ext4_mark_inode_dirty(handle, inode);
+	}
+out_stop:
 	ext4_journal_stop(handle);
 	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 		goto retry;


Patches currently in stable-queue which might be from jack@suse.cz are

queue-4.12/ext4-preserve-i_mode-if-__ext4_set_acl-fails.patch
queue-4.12/ext4-don-t-clear-sgid-when-inheriting-acls.patch
queue-4.12/ext4-fix-seek_hole-seek_data-for-blocksize-pagesize.patch
queue-4.12/ocfs2-don-t-clear-sgid-when-inheriting-acls.patch