On 07/18/2018 04:14 AM, David Howells wrote:
> Dave Jiang <[email protected]> wrote:
>
>> Add support for setting and/or updating passphrase on the Intel nvdimms.
>> The passphrase is pulled from userspace through the kernel key management.
>> We trigger the update via writing "update" to the sysfs attribute
>> "security". The state of the security can also be read via the "security"
>> attribute. libnvdimm will generically support the key_change API call.
>
> Btw, could you use a logon-type key rather than spinning your own? Do you
> specifically not want it to be updateable?
Ok stupid question David. I'm attempting to use the logon-type key. I
have added this line to the request-key.conf:
create logon nvdimm* * /usr/sbin/nvdimm-upcall %k
But I can't seem to get /sbin/request-key to trigger this line and call
my upcall app.
On the kernel side it seems ok?
==>
search_nested_keyrings({17212177},{logon,nvdimm.update:cdab-0a-07e0-ffffffff})
<== call_sbin_request_key() = -126
<== construct_key() = -126
cons failed
What am I doing wrong?
>
>> +static int intel_dimm_security_update_passphrase(
>> + struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
>> + struct nvdimm_key_data *old_data,
>> + struct nvdimm_key_data *new_data)
>
> You might want to mark old_data and new_data as const here. At least, they
> don't appear to be changed. Also, can you stick a banner comment on the
> function to say what it actually does? Is it changing the key stored in h/w
> or is it meant to be changing what's stored in the key payload?
>
>> + /* request new key from userspace */
>> + key = nvdimm_request_key(dev);
>> + if (!key) {
>> + dev_dbg(dev, "%s: failed to acquire new key\n", __func__);
>> + return -ENXIO;
>> + }
>> +
>> + dev_dbg(dev, "%s: new key: %#x\n", __func__, key->serial);
>> +
>> + if (key->datalen == NVDIMM_PASSPHRASE_LEN) {
>> + old_data = NULL;
>> + new_data = key->payload.data[0];
>> + } else if (key->datalen == (NVDIMM_PASSPHRASE_LEN * 2)) {
>> + new_data = key->payload.data[0];
>> + old_data = new_data + NVDIMM_PASSPHRASE_LEN;
>> + } else {
>> + key_invalidate(key);
>> + key_put(key);
>> + dev_warn(dev, "Incorrect key payload size for update: %u\n",
>> + key->datalen);
>> + return -EINVAL;
>> + }
>> +
>> + down_read(&key->sem);
>> + rc = nvdimm->security_ops->change_key(nvdimm_bus, nvdimm, old_data,
>> + new_data);
>
> Why do you need to get a read lock on key->sem and not a write-lock?
>
>> + if (rc == 0 && key->datalen == (NVDIMM_PASSPHRASE_LEN * 2))
>> + memcpy(old_data, new_data, NVDIMM_PASSPHRASE_LEN);
>
> You appear to be changing the key content here. If that's the case, don't you
> need to write-lock key->sem?
>
>> + up_read(&key->sem);
>
> David
>
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