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authorDarrick J. Wong <darrick.wong@oracle.com>2017-05-12 10:44:10 -0700
committerDarrick J. Wong <darrick.wong@oracle.com>2017-05-16 12:26:16 -0700
commitea9a46e1c49251331dbfda19ced7114337966178 (patch)
tree1b1f419d0d072a89b68c6af51a8e7cba9742eba1
parent892d2a5f705723b2cb488bfb38bcbdcf83273184 (diff)
xfs: only return detailed fsmap info if the caller has CAP_SYS_ADMIN
There were a number of handwaving complaints that one could "possibly" use inode numbers and extent maps to fingerprint a filesystem hosting multiple containers and somehow use the information to guess at the contents of other containers and attack them. Despite the total lack of any demonstration that this is actually possible, it's easier to restrict access now and broaden it later, so use the rmapbt fsmap backends only if the caller has CAP_SYS_ADMIN. Unprivileged users will just have to make do with only getting the free space and static metadata placement information. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
-rw-r--r--fs/xfs/xfs_fsmap.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 3683819887a5..814ed729881d 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -828,6 +828,7 @@ xfs_getfsmap(
struct xfs_fsmap dkeys[2]; /* per-dev keys */
struct xfs_getfsmap_dev handlers[XFS_GETFSMAP_DEVS];
struct xfs_getfsmap_info info = { NULL };
+ bool use_rmap;
int i;
int error = 0;
@@ -837,12 +838,14 @@ xfs_getfsmap(
!xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[1]))
return -EINVAL;
+ use_rmap = capable(CAP_SYS_ADMIN) &&
+ xfs_sb_version_hasrmapbt(&mp->m_sb);
head->fmh_entries = 0;
/* Set up our device handlers. */
memset(handlers, 0, sizeof(handlers));
handlers[0].dev = new_encode_dev(mp->m_ddev_targp->bt_dev);
- if (xfs_sb_version_hasrmapbt(&mp->m_sb))
+ if (use_rmap)
handlers[0].fn = xfs_getfsmap_datadev_rmapbt;
else
handlers[0].fn = xfs_getfsmap_datadev_bnobt;