[PATCH 3.16 119/192] ext3: Don't clear SGID when inheriting ACLs

Ben Hutchings
2017-10-09T13:08:49Z

From: Ben Hutchings <ben@decadent.org.uk>

Based on Jan Kara's fix for ext2 (commit a992f2d38e4c), from which the
following description is taken:

> 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 the posix_acl_update_mode() call up from
__ext3_set_acl() into ext3_set_acl().

Fixes: 073931017b49 ("posix_acl: Clear SGID bit when setting file permissions")
Cc: linux-ext4@vger.kernel.org
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/ext3/acl.c | 36 ++++++++++++++++++++++--------------
1 file changed, 22 insertions(+), 14 deletions(-)

--- a/fs/ext3/acl.c
+++ b/fs/ext3/acl.c
@@ -194,13 +194,6 @@ __ext3_set_acl(handle_t *handle, struct
switch(type) {
case ACL_TYPE_ACCESS:
name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
- if (acl) {
- error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
- if (error)
- return error;
- inode->i_ctime = CURRENT_TIME_SEC;
- ext3_mark_inode_dirty(handle, inode);
- }
break;

case ACL_TYPE_DEFAULT:
@@ -239,7 +232,15 @@ retry:
handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
if (IS_ERR(handle))
return PTR_ERR(handle);
+ if (type == ACL_TYPE_ACCESS && acl) {
+ error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
+ if (error)
+ goto journal_stop;
+ inode->i_ctime = CURRENT_TIME_SEC;
+ ext3_mark_inode_dirty(handle, inode);
+ }
error = __ext3_set_acl(handle, inode, type, acl);
+journal_stop:
ext3_journal_stop(handle);
if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
goto retry;