[libvirt] [PATCH] qemu: Use correct permissions when determining the image chain

[Eric Blake]

On 02/07/2014 10:53 AM, Peter Krempa wrote:
> The code took into account only the global permissions. The domains now
> support per-vm DAC lables and per-image DAC labels. Use the most

s/lables/labels/

> specific label available.
> ---
>  src/qemu/qemu_domain.c  | 35 +++++++++++++++++++++++++++++++++--
>  src/qemu/qemu_domain.h  |  1 +
>  src/qemu/qemu_driver.c  |  8 ++++----
>  src/qemu/qemu_hotplug.c |  2 +-
>  src/qemu/qemu_process.c |  2 +-
>  5 files changed, 40 insertions(+), 8 deletions(-)

> +static void
> +qemuDomainGetImageIds(virQEMUDriverConfigPtr cfg,
> +                      virDomainObjPtr vm,
> +                      virDomainDiskDefPtr disk,
> +                      uid_t *uid, gid_t *gid)
> +{
> +    virSecurityLabelDefPtr vmlabel;
> +    virSecurityDeviceLabelDefPtr disklabel;

Here, I'd add:

if (uid)
    *uid = -1;
if (gid)
    *gid = -1;

> +
> +    if (cfg) {
> +        if (uid)
> +            *uid = cfg->user;
> +
> +        if (gid)
> +            *gid = cfg->group;
> +    }
> +
> +    if (vm && (vmlabel = virDomainDefGetSecurityLabelDef(vm->def, "dac")))
> +        virParseOwnershipIds(vmlabel->label, uid, gid);
> +
> +    if ((disklabel = virDomainDiskDefGetSecurityLabelDef(disk, "dac")))
> +        virParseOwnershipIds(disklabel->label, uid, gid);

since all three of these more-specific overrides could all be missing,
but ideally, you want to guarantee that we picked the best-possible
uid/gid by the end of this method.

ACK with that fixed - it means that all disks are now being opened by
the same credentials as what we tell qemu to open with.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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