When group ownership is changed a caller whose fsuid owns the inode can
change the group of the inode to any group they are a member of. When
searching through the caller's groups we failed to use the gid mapped
according to the idmapped mount otherwise we fail to change ownership.
Add a test for this.
Cc: Seth Forshee <sforshee@xxxxxxxxxxxxxxxx>
Cc: Amir Goldstein <amir73il@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Aleksa Sarai <cyphar@xxxxxxxxxx>
Cc: <fstests@xxxxxxxxxxxxxxx>
Signed-off-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>
---
/* v2 */
- Zorro Lang <zlang@xxxxxxxxxx>:
- various minor fixes
- Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>:
- Expand test to also cover overlayfs on top of idmapped mounts.
---
tests/generic/692 | 181 ++++++++++++++++++++++++++++++++++++++++++
tests/generic/692.out | 31 ++++++++
2 files changed, 212 insertions(+)
create mode 100755 tests/generic/692
create mode 100644 tests/generic/692.out
diff --git a/tests/generic/692 b/tests/generic/692
new file mode 100755
index 00000000..9c982c8a
--- /dev/null
+++ b/tests/generic/692
@@ -0,0 +1,181 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022 Christian Brauner (Microsoft). All Rights Reserved.
+#
+# FS QA Test 692
+#
+# Test that users can changed group ownership of a file they own to a group
+# they are a member of.
+#
+# Regression test for commit:
+#
+# 168f91289340 ("fs: account for group membership")
+#
+. ./common/preamble
+_begin_fstest auto quick perms attr idmapped mount
+
+# Override the default cleanup function.
+_cleanup()
+{
+ cd /
+ $UMOUNT_PROG $SCRATCH_MNT/target-mnt 2>/dev/null
+ $UMOUNT_PROG $SCRATCH_MNT/ovl-merge 2>/dev/null
+ $UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
+ rm -r -f $tmp.*
+}
+
+# real QA test starts here
+_supported_fs ^overlay
+_require_extra_fs overlay
+_supports_filetype $SCRATCH_MNT || _notrun "overlayfs test requires d_type"
+_require_scratch
+_require_chown
+_require_idmapped_mounts
+_require_test_program "vfs/mount-idmapped"
+_require_user fsgqa2
+_require_group fsgqa2
+# Do this SECOND so that qa_user is fsgqa, and _user_do uses that account
+_require_user fsgqa
+_require_group fsgqa
+
+_scratch_mkfs >> $seqres.full
+_scratch_mount
+
+uqid=`id -u fsgqa`
+gqid=`id -g fsgqa`
+uqid2=`id -u fsgqa2`
+gqid2=`id -g fsgqa2`
+
+setup_tree()
+{
+ mkdir -p $SCRATCH_MNT/source-mnt
+ chmod 0777 $SCRATCH_MNT/source-mnt
+ touch $SCRATCH_MNT/source-mnt/file1
+ chown 65534:65534 $SCRATCH_MNT
+ chown 65534:65534 $SCRATCH_MNT/source-mnt
+ chown 65534:65535 $SCRATCH_MNT/source-mnt/file1
+
+ mkdir -p $SCRATCH_MNT/target-mnt
+ chmod 0777 $SCRATCH_MNT/target-mnt
+}
+
+# Setup an idmapped mount where uid and gid 65534 are mapped to fsgqa and uid
+# and gid 65535 are mapped to fsgqa2.
+setup_idmapped_mnt()
+{
+ $here/src/vfs/mount-idmapped \
+ --map-mount=u:65534:$uqid:1 \
+ --map-mount=g:65534:$gqid:1 \
+ --map-mount=u:65535:$uqid2:1 \
+ --map-mount=g:65535:$gqid2:1 \
+ $SCRATCH_MNT/source-mnt $SCRATCH_MNT/target-mnt
+}
+
+# We've created a layout where fsgqa owns the target file but the group of the
+# target file is owned by another group. We now test that user fsgqa can change
+# the group ownership of the file to a group they control. In this case to the
+# fsgqa group.
+change_group_ownership()
+{
+ local path="$1"
+
+ stat -c '%U:%G' $path
+ _user_do "id -u --name; id -g --name; chgrp $gqid $path"
+ stat -c '%U:%G' $path
+}
+
+reset_ownership()
+{
+ local path="$SCRATCH_MNT/source-mnt/file1"
+
+ echo ""
+ echo "reset ownership"
+ chown 65534:65534 $path
+ stat -c '%u:%g' $path
+ chown 65534:65535 $path
+ stat -c '%u:%g' $path
+}
+
+# Basic test as explained in the comment for change_group_ownership().
+run_base_test()
+{
+ echo ""
+ echo "base idmapped test"
+ change_group_ownership "$SCRATCH_MNT/target-mnt/file1"
+ reset_ownership
+}
+
+lower="$SCRATCH_MNT/target-mnt"
+upper="$SCRATCH_MNT/ovl-upper"
+work="$SCRATCH_MNT/ovl-work"
+merge="$SCRATCH_MNT/ovl-merge"
+
+# Prepare overlayfs with metacopy turned off.
+setup_overlayfs_idmapped_lower_metacopy_off()
+{
+ mkdir $upper
+ mkdir $work
+ mkdir $merge
+
+ mount -t overlay overlay -o "lowerdir=$lower,upperdir=$upper,workdir=$work,metacopy=off" $merge || _notrun "overlayfs test doesn't support idmappped layers"
+}
+
+# Prepare overlayfs with metacopy turned on.
+setup_overlayfs_idmapped_lower_metacopy_on()
+{
+ mkdir $upper
+ mkdir $work
+ mkdir $merge
+
+ mount -t overlay overlay -o "lowerdir=$lower,upperdir=$upper,workdir=$work,metacopy=on" $merge
+}
+
+reset_overlayfs()
+{
+ rm -rf $upper
+ rm -rf $work
+ $UMOUNT_PROG $SCRATCH_MNT/ovl-merge 2>/dev/null
+ rm -rf $merge
+}
+
+# Overlayfs can be mounted on top of idmapped layers. Make sure that the basic
+# test explained in the comment for change_group_ownership() passes with
+# overlayfs mounted on top of it.
+# This tests overlayfs with metacopy turned off, i.e., changing a file copies
+# up data and metadata.
+run_overlayfs_idmapped_lower_metacopy_off()
+{
+ echo ""
+ echo "overlayfs idmapped lower metacopy off"
+ change_group_ownership "$SCRATCH_MNT/ovl-merge/file1"
+ reset_overlayfs
+ reset_ownership
+}
+
+# Overlayfs can be mounted on top of idmapped layers. Make sure that the basic
+# test explained in the comment for change_group_ownership() passes with
+# overlayfs mounted on top of it.
+# This tests overlayfs with metacopy turned on, i.e., changing a file tries to
+# only copy up metadata.
+run_overlayfs_idmapped_lower_metacopy_on()
+{
+ echo ""
+ echo "overlayfs idmapped lower metacopy on"
+ change_group_ownership "$SCRATCH_MNT/ovl-merge/file1"
+ reset_overlayfs
+ reset_ownership
+}
+
+setup_tree
+setup_idmapped_mnt
+run_base_test
+
+setup_overlayfs_idmapped_lower_metacopy_off
+run_overlayfs_idmapped_lower_metacopy_off
+
+setup_overlayfs_idmapped_lower_metacopy_on
+run_overlayfs_idmapped_lower_metacopy_on
+
+# success, all done
+status=0
+exit
diff --git a/tests/generic/692.out b/tests/generic/692.out
new file mode 100644
index 00000000..bda8400e
--- /dev/null
+++ b/tests/generic/692.out
@@ -0,0 +1,31 @@
+QA output created by 692
+
+base idmapped test
+fsgqa:fsgqa2
+fsgqa
+fsgqa
+fsgqa:fsgqa
+
+reset ownership
+65534:65534
+65534:65535
+
+overlayfs idmapped lower metacopy off
+fsgqa:fsgqa2
+fsgqa
+fsgqa
+fsgqa:fsgqa
+
+reset ownership
+65534:65534
+65534:65535
+
+overlayfs idmapped lower metacopy on
+fsgqa:fsgqa2
+fsgqa
+fsgqa
+fsgqa:fsgqa
+
+reset ownership
+65534:65534
+65534:65535
base-commit: 568ac9fffeb6afec03e5d6c9936617232fd7fc6d
--
2.34.1
