Re: [PATCH 4/4] iotests/308: Test allow-other

[Kevin Wolf]

Am 14.06.2021 um 16:44 hat Max Reitz geschrieben:
> We cannot reasonably test the main point of allow-other, which is to
> allow users other than the current one to access the FUSE export,
> because that would require access to sudo, which this test most likely
> will not have.  (Also, we would need to figure out some user/group that
> is on the machine and that is not the current user/group, which may
> become a bit hairy.)
> 
> But we can test some byproducts: First, whether changing permissions
> works (our FUSE code only allows so for allow-other=true), and second,
> whether the kernel applies permission checks with allow-other=true
> (because that implies default_permissions).
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>

This seems to have the problem that you mentioned:

--- /home/kwolf/source/qemu/tests/qemu-iotests/308.out
+++ 308.out.bad
@@ -205,7 +205,9 @@
          'writable': true,
          'allow-other': true
           } }
-{"return": {}}
+fusermount3: option allow_other only allowed if 'user_allow_other' is set in 
/etc/fuse.conf
+{"error": {"class": "GenericError", "desc": "Failed to mount FUSE session to 
export"}}
+Timeout waiting for return on handle 2
 (Invoking chmod)
 Permissions post-chmod: 666
 (Removing all permissions)

Maybe it should be a separate test case that is skipped with
user_allow_other is disabled.

>  tests/qemu-iotests/308     | 91 ++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/308.out | 47 ++++++++++++++++++++
>  2 files changed, 138 insertions(+)
> 
> diff --git a/tests/qemu-iotests/308 b/tests/qemu-iotests/308
> index f122065d0f..1b2f908947 100755
> --- a/tests/qemu-iotests/308
> +++ b/tests/qemu-iotests/308
> @@ -334,6 +334,97 @@ echo '=== Compare copy with original ==='
>  
>  $QEMU_IMG compare -f raw -F $IMGFMT "$COPIED_IMG" "$TEST_IMG"
>  
> +echo
> +echo '=== Test permissions ==='
> +
> +# Test that you can only change permissions on the export with 
> allow-other=true.
> +# We cannot really test the primary reason behind allow-other (i.e. to allow
> +# users other than the current one access to the export), because for that we
> +# would need sudo, which realistically nobody will allow this test to use.
> +# What we can do is test that allow-other=true also enables 
> default_permissions,
> +# i.e. whether we can still read from the file if we remove the read 
> permission.

We already have other test cases that use sudo if available. Though I
guess it means that these tests aren't run very often.

Kevin