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| author | Darrick J. Wong <djwong@kernel.org> | 2021-07-12 22:58:51 +0300 |
|---|---|---|
| committer | Darrick J. Wong <djwong@kernel.org> | 2021-07-15 19:58:42 +0300 |
| commit | 5aa5b278237f356f86205c4b03d4cc64a293850a (patch) | |
| tree | 6d86418555329aece03357a9b55144712f626a8d /fs/xfs/xfs_ioctl.c | |
| parent | 83193e5ebb0164d612aa620ceab7d3746e80e2a4 (diff) | |
| download | linux-5aa5b278237f356f86205c4b03d4cc64a293850a.tar.xz | |
xfs: don't expose misaligned extszinherit hints to userspace
Commit 603f000b15f2 changed xfs_ioctl_setattr_check_extsize to reject an
attempt to set an EXTSZINHERIT extent size hint on a directory with
RTINHERIT set if the hint isn't a multiple of the realtime extent size.
However, I have recently discovered that it is possible to change the
realtime extent size when adding a rt device to a filesystem, which
means that the existence of directories with misaligned inherited hints
is not an accident.
As a result, it's possible that someone could have set a valid hint and
added an rt volume with a different rt extent size, which invalidates
the ondisk hints. After such a sequence, FSGETXATTR will report a
misaligned hint, which FSSETXATTR will trip over, causing confusion if
the user was doing the usual GET/SET sequence to change some other
attribute. Change xfs_fill_fsxattr to omit the hint if it isn't aligned
properly.
Fixes: 603f000b15f2 ("xfs: validate extsz hints against rt extent size when rtinherit is set")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs/xfs_ioctl.c')
| -rw-r--r-- | fs/xfs/xfs_ioctl.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c index 275d1c3123bd..16039ea10ac9 100644 --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -1065,7 +1065,24 @@ xfs_fill_fsxattr( fileattr_fill_xflags(fa, xfs_ip2xflags(ip)); - fa->fsx_extsize = XFS_FSB_TO_B(mp, ip->i_extsize); + if (ip->i_diflags & XFS_DIFLAG_EXTSIZE) { + fa->fsx_extsize = XFS_FSB_TO_B(mp, ip->i_extsize); + } else if (ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT) { + /* + * Don't let a misaligned extent size hint on a directory + * escape to userspace if it won't pass the setattr checks + * later. + */ + if ((ip->i_diflags & XFS_DIFLAG_RTINHERIT) && + ip->i_extsize % mp->m_sb.sb_rextsize > 0) { + fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | + FS_XFLAG_EXTSZINHERIT); + fa->fsx_extsize = 0; + } else { + fa->fsx_extsize = XFS_FSB_TO_B(mp, ip->i_extsize); + } + } + if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) fa->fsx_cowextsize = XFS_FSB_TO_B(mp, ip->i_cowextsize); fa->fsx_projid = ip->i_projid; |