[libvirt] [PATCH 2/2] security: aa-helper: gl devices in sysfs at arbitrary depth

[Jamie Strandboge]

On Tue, 05 Mar 2019, Christian Ehrhardt wrote:

> Further testing with more devices showed that we sometimes have a
> different depth of pci device paths when accessing sysfs for device
> attributes.
> 
> But since the access is limited to a set of filenames and read only it
> is safe to use a wildcard for that.
> 
> Related apparmor denies - while we formerly had only considered:
> apparmor="DENIED" operation="open"
>   name="/sys/devices/pci0000:00/0000:00:02.1/uevent"
>   requested_mask="r"
> 
> We now also know of cases like:
> apparmor="DENIED" operation="open"
>   name="/sys/devices/pci0000:00/0000:00:03.1/0000:1c:00.0/uevent"
>   requested_mask="r"
> 
> Fixes: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1817943
> 
> Signed-off-by: Christian Ehrhardt <christian.ehrhardt at canonical.com>
> ---
>  src/security/virt-aa-helper.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
> index 13b507ff69..989dcf1784 100644
> --- a/src/security/virt-aa-helper.c
> +++ b/src/security/virt-aa-helper.c
> @@ -1286,8 +1286,7 @@ get_files(vahControl * ctl)
>          virBufferAddLit(&buf, "  \"/dev/nvidiactl\" rw,\n");
>          virBufferAddLit(&buf, "  # Probe DRI device attributes\n");
>          virBufferAddLit(&buf, "  \"/dev/dri/\" r,\n");
> -        virBufferAddLit(&buf, "  \"/sys/devices/*/*/{uevent,vendor,device,subsystem_vendor,subsystem_device}\" r,\n");
> -        virBufferAddLit(&buf, "  \"/sys/devices/*/*/drm/*/{uevent,vendor,device,subsystem_vendor,subsystem_device}\" r,\n");
> +        virBufferAddLit(&buf, "  \"/sys/devices/**/{uevent,vendor,device,subsystem_vendor,subsystem_device}\" r,\n");

I'm curious about the new denials, but the reads for these files should be
fine.

-- 
Jamie Strandboge             | http://www.canonical.com
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