[PATCH] xfs: fix sgid inheritance for subdirectories inheriting default acls [V2]

Carlos Maiolino
2013-06-18T15:32:26Z

XFS removes sgid bits of subdirectories under a directory containing a default
acl.

When a default acl is set, it implies xfs to call xfs_setattr_nonsize() in its
code path. Such function is shared among mkdir and chmod system calls, and
does some checks unneeded by mkdir (calling inode_change_ok()). Such checks
remove sgid bit from the inode after it has been granted.

With this patch, we extend the meaning of XFS_ATTR_NOACL flag to avoid these
checks when acls are being inherited (thanks hch).

Also, xfs_setattr_mode, doesn't need to re-check for group id and capabilities
permissions, this only implies in another try to remove sgid bit from the
directories. Such check is already done either on inode_change_ok() or
xfs_setattr_nonsize().

Changelog:

V2: Extends the meaning of XFS_ATTR_NOACL instead of wrap the tests into another
function

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
fs/xfs/xfs_iops.c | 27 ++++++++++++++-------------
1 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index ca9ecaa..3547d89 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -467,9 +467,6 @@ xfs_setattr_mode(
ASSERT(tp);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));

- if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
- mode &= ~S_ISGID;
-
ip->i_d.di_mode &= S_IFMT;
ip->i_d.di_mode |= mode & ~S_IFMT;

@@ -495,15 +492,18 @@ xfs_setattr_nonsize(

trace_xfs_setattr(ip);

- if (mp->m_flags & XFS_MOUNT_RDONLY)
- return XFS_ERROR(EROFS);
+ /* If acls are being inherited, we already have this checked */
+ if (!(flags & XFS_ATTR_NOACL)) {
+ if (mp->m_flags & XFS_MOUNT_RDONLY)
+ return XFS_ERROR(EROFS);

- if (XFS_FORCED_SHUTDOWN(mp))
- return XFS_ERROR(EIO);
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return XFS_ERROR(EIO);

- error = -inode_change_ok(inode, iattr);
- if (error)
- return XFS_ERROR(error);
+ error = -inode_change_ok(inode, iattr);
+ if (error)
+ return XFS_ERROR(error);
+ }

ASSERT((mask & ATTR_SIZE) == 0);

@@ -594,9 +594,10 @@ xfs_setattr_nonsize(
* The set-user-ID and set-group-ID bits of a file will be
* cleared upon successful return from chown()
*/
- if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) &&
- !capable(CAP_FSETID))
- ip->i_d.di_mode &= ~(S_ISUID|S_ISGID);
+ if (!S_ISDIR(inode->i_mode))
+ if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) &&
+ !capable(CAP_FSETID))
+ ip->i_d.di_mode &= ~(S_ISUID|S_ISGID);

/*
* Change the ownerships and register quota modifications
--
1.7.1