iotests/fuse-allow-other: Test allow-other

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210625142317.271673-7-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/tests/fuse-allow-other

+#!/usr/bin/env bash
+# group: rw
+#
+# Test FUSE exports' allow-other option
+#
+# Copyright (C) 2021 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+seq=$(basename "$0")
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_qemu
+    _cleanup_test_img
+    rm -f "$EXT_MP"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ../common.rc
+. ../common.filter
+. ../common.qemu
+
+_supported_fmt generic
+
+_supported_proto file # We create the FUSE export manually
+
+sudo -n -u nobody true || \
+    _notrun 'Password-less sudo as nobody required to test allow_other'
+
+# $1: Export ID
+# $2: Options (beyond the node-name and ID)
+# $3: Expected return value (defaults to 'return')
+# $4: Node to export (defaults to 'node-format')
+fuse_export_add()
+{
+    allow_other_not_supported='option allow_other only allowed if'
+
+    output=$(
+        success_or_failure=yes _send_qemu_cmd $QEMU_HANDLE \
+            "{'execute': 'block-export-add',
+              'arguments': {
+                  'type': 'fuse',
+                  'id': '$1',
+                  'node-name': '${4:-node-format}',
+                  $2
+              } }" \
+            "${3:-return}" \
+            "$allow_other_not_supported" \
+            | _filter_imgfmt
+    )
+
+    if echo "$output" | grep -q "$allow_other_not_supported"; then
+        # Shut down qemu gracefully so it can unmount the export
+        _send_qemu_cmd $QEMU_HANDLE \
+            "{'execute': 'quit'}" \
+            'return'
+
+        wait=yes _cleanup_qemu
+
+        _notrun "allow_other not supported"
+    fi
+
+    echo "$output"
+}
+
+EXT_MP="$TEST_DIR/fuse-export"
+
+_make_test_img 64k
+touch "$EXT_MP"
+
+echo
+echo '=== Test permissions ==='
+
+# $1: allow-other value ('on'/'off'/'auto')
+run_permission_test()
+{
+    _launch_qemu \
+        -blockdev \
+        "$IMGFMT,node-name=node-format,file.driver=file,file.filename=$TEST_IMG"
+
+    _send_qemu_cmd $QEMU_HANDLE \
+        "{'execute': 'qmp_capabilities'}" \
+        'return'
+
+    fuse_export_add 'export' \
+        "'mountpoint': '$EXT_MP',
+         'allow-other': '$1'"
+
+    # Should always work
+    echo '(Removing all permissions)'
+    chmod 000 "$EXT_MP" 2>&1 | _filter_testdir | _filter_imgfmt
+    stat -c 'Permissions post-chmod: %a' "$EXT_MP"
+
+    # Should always work
+    echo '(Granting u+r)'
+    chmod u+r "$EXT_MP" 2>&1 | _filter_testdir | _filter_imgfmt
+    stat -c 'Permissions post-chmod: %a' "$EXT_MP"
+
+    # Should only work with allow-other: Otherwise, no permissions can be
+    # granted to the group or others
+    echo '(Granting read permissions for everyone)'
+    chmod 444 "$EXT_MP" 2>&1 | _filter_testdir | _filter_imgfmt
+    stat -c 'Permissions post-chmod: %a' "$EXT_MP"
+
+    echo 'Doing operations as nobody:'
+    # Change to TEST_DIR, so nobody will not have to attempt a lookup
+    pushd "$TEST_DIR" >/dev/null
+
+    # This is already prevented by the permissions (without allow-other, FUSE
+    # exports always have o-r), but test it anyway
+    sudo -n -u nobody cat fuse-export >/dev/null
+
+    # If the only problem were the lack of permissions, we should still be able
+    # to stat the export as nobody; it should not work without allow-other,
+    # though
+    sudo -n -u nobody \
+        stat -c 'Permissions seen by nobody: %a' fuse-export 2>&1 \
+        | _filter_imgfmt
+
+    # To prove the point, revoke read permissions for others and try again
+    chmod o-r fuse-export 2>&1 | _filter_testdir | _filter_imgfmt
+
+    # Should fail
+    sudo -n -u nobody cat fuse-export >/dev/null
+    # Should work with allow_other
+    sudo -n -u nobody \
+        stat -c 'Permissions seen by nobody: %a' fuse-export 2>&1 \
+        | _filter_imgfmt
+
+    popd >/dev/null
+
+    _send_qemu_cmd $QEMU_HANDLE \
+        "{'execute': 'quit'}" \
+        'return'
+
+    wait=yes _cleanup_qemu
+}
+
+# 'auto' should behave exactly like 'on', because 'on' tests that
+# allow_other works (otherwise, this test is skipped)
+for ao in off on auto; do
+    echo
+    echo "--- allow-other=$ao ---"
+
+    run_permission_test "$ao"
+done
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/tests/fuse-allow-other.out

+QA output created by fuse-allow-other
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=65536
+
+=== Test permissions ===
+
+--- allow-other=off ---
+{'execute': 'qmp_capabilities'}
+{"return": {}}
+{'execute': 'block-export-add',
+              'arguments': {
+                  'type': 'fuse',
+                  'id': 'export',
+                  'node-name': 'node-format',
+                  'mountpoint': 'TEST_DIR/fuse-export',
+         'allow-other': 'off'
+              } }
+{"return": {}}
+(Removing all permissions)
+Permissions post-chmod: 0
+(Granting u+r)
+Permissions post-chmod: 400
+(Granting read permissions for everyone)
+chmod: changing permissions of 'TEST_DIR/fuse-export': Operation not permitted
+Permissions post-chmod: 400
+Doing operations as nobody:
+cat: fuse-export: Permission denied
+stat: cannot statx 'fuse-export': Permission denied
+cat: fuse-export: Permission denied
+stat: cannot statx 'fuse-export': Permission denied
+{'execute': 'quit'}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_EXPORT_DELETED", "data": {"id": "export"}}
+
+--- allow-other=on ---
+{'execute': 'qmp_capabilities'}
+{"return": {}}
+{'execute': 'block-export-add',
+              'arguments': {
+                  'type': 'fuse',
+                  'id': 'export',
+                  'node-name': 'node-format',
+                  'mountpoint': 'TEST_DIR/fuse-export',
+         'allow-other': 'on'
+              } }
+{"return": {}}
+(Removing all permissions)
+Permissions post-chmod: 0
+(Granting u+r)
+Permissions post-chmod: 400
+(Granting read permissions for everyone)
+Permissions post-chmod: 444
+Doing operations as nobody:
+Permissions seen by nobody: 444
+cat: fuse-export: Permission denied
+Permissions seen by nobody: 440
+{'execute': 'quit'}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_EXPORT_DELETED", "data": {"id": "export"}}
+
+--- allow-other=auto ---
+{'execute': 'qmp_capabilities'}
+{"return": {}}
+{'execute': 'block-export-add',
+              'arguments': {
+                  'type': 'fuse',
+                  'id': 'export',
+                  'node-name': 'node-format',
+                  'mountpoint': 'TEST_DIR/fuse-export',
+         'allow-other': 'auto'
+              } }
+{"return": {}}
+(Removing all permissions)
+Permissions post-chmod: 0
+(Granting u+r)
+Permissions post-chmod: 400
+(Granting read permissions for everyone)
+Permissions post-chmod: 444
+Doing operations as nobody:
+Permissions seen by nobody: 444
+cat: fuse-export: Permission denied
+Permissions seen by nobody: 440
+{'execute': 'quit'}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_EXPORT_DELETED", "data": {"id": "export"}}
+*** done