[libvirt] [PATCH] secret: Add check/validation for correct usage when LookupByUUID

[John Ferlan]

On 12/12/18 9:29 AM, Michal Privoznik wrote:
> On 12/4/18 9:32 PM, John Ferlan wrote:
>> If virSecretGetSecretString is using by secretLookupByUUID,
>> then it's possible the found sec->usageType doesn't match the
>> desired @secretUsageType. If this occurs for the encrypted
>> volume creation processing and a subsequent pool refresh is
>> executed, then the secret used to create the volume will not
>> be found by the storageBackendLoadDefaultSecrets which expects
>> to find secrets by VIR_SECRET_USAGE_TYPE_VOLUME.
>>
>> Add a check to virSecretGetSecretString to avoid the possibility
>> along with an error indicating the incorrect matched types.
>>
>> Signed-off-by: John Ferlan <jferlan at redhat.com>
>> ---
>>
>>  If someone has an idea regarding how the usage could be filled
>>  in "properly" for the qemuxml2argvtest, I'm willing to give it
>>  a shot. However, fair warning trying to "mock" for tls, volume,
>>  iscsi, and ceph could be rather painful. Thus the NONE was the
>>  well, easiest way to go since the stored secret (ahem) shouldn't
>>  be of usageType "none" (famous last words).
>>
>>  src/secret/secret_util.c | 17 +++++++++++++++++
>>  tests/qemuxml2argvtest.c |  4 +++-
>>  2 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/secret/secret_util.c b/src/secret/secret_util.c
>> index 16e43ab2cc..27e164a425 100644
>> --- a/src/secret/secret_util.c
>> +++ b/src/secret/secret_util.c
>> @@ -71,6 +71,23 @@ virSecretGetSecretString(virConnectPtr conn,
>>      if (!sec)
>>          goto cleanup;
>>  
>> +    /* NB: NONE is a byproduct of the qemuxml2argvtest test mocking
>> +     * for UUID lookups. Normal secret XML processing would fail if
>> +     * the usage type was NONE and since we have no way to set the
>> +     * expected usage in that environment, let's just accept NONE */
>> +    if (sec->usageType != VIR_SECRET_USAGE_TYPE_NONE &&
>> +        sec->usageType != secretUsageType) {
>> +        char uuidstr[VIR_UUID_STRING_BUFLEN];
>> +
>> +        virUUIDFormat(seclookupdef->u.uuid, uuidstr);
>> +        virReportError(VIR_ERR_INVALID_ARG,
>> +                       _("secret with uuid %s is of type '%s' not "
>> +                         "expected '%s' type"),
>> +                       uuidstr, virSecretUsageTypeToString(sec->usageType),
>> +                       virSecretUsageTypeToString(secretUsageType));
>> +        goto cleanup;
>> +    }
> 
> I don't quite understand why this is needed. I mean, if
> seclookupdef->type == VIR_SECRET_LOOKUP_TYPE_USAGE then this check is
> done while looking the secret up. If seclookupdef->type ==
> VIR_SECRET_LOOKUP_TYPE_UUID then this check feels odd; the caller wants
> the secret by UUID and they don't care about the usage type.
> 
> Is there an actual error you're seeing?
> 
> Michal
> 

Someone used an "iscsi" usage type secret by to create their luks
encrypted volume. When using vol-dumpxml after creation the secret by
usage existed. Then a pool-refresh caused the secret to disappear
because on pool refresh the secret for a volume is refreshed by "volume"
secret usage type.  When I posted this patch, the bz didn't exist, but
it does now, see: https://bugzilla.redhat.com/show_bug.cgi?id=1656255

John