From: Dave Jiang <dave.jiang@intel.com>
To: David Howells <dhowells@redhat.com>
Cc: alison.schofield@intel.com, keescook@chromium.org,
linux-nvdimm@lists.01.org, ebiggers3@gmail.com,
keyrings@vger.kernel.org
Subject: Re: [PATCH v8 06/12] nfit/libnvdimm: add set passphrase support for Intel nvdimms
Date: Fri, 21 Sep 2018 17:25:08 -0700 [thread overview]
Message-ID: <c804ec81-68c5-3e11-c65f-1226e68a4b2b@intel.com> (raw)
In-Reply-To: <19459.1537574236@warthog.procyon.org.uk>
On 09/21/2018 04:57 PM, David Howells wrote:
> Dave Jiang <dave.jiang@intel.com> wrote:
>
>> + new_key = key_alloc(&key_type_logon, key->description,
>> + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, &init_cred, 0,
>
> KEY_POS_SEARCH? KEY_USR_VIEW?
>
>> + KEY_ALLOC_NOT_IN_QUOTA, NULL);
>> + ...
>> + down_read(&key->sem);
>> + payload = key->payload.data[0];
>> + rc = key_instantiate_and_link(new_key, payload->data, key->datalen,
>
> payload->datalen, not key->datalen.
>
>> + nvdimm_keyring, NULL);
>
> Okay, that's a weird way of going about things. I presume you don't want to
> add key to nvdimm_keyring - maybe in case it gets updated whilst you're using
> it and your private key isn't in quota?
>
>> + up_read(&key->sem);
>> + if (rc < 0) {
>> + key_revoke(new_key);
>> + key_put(new_key);
>> + return NULL;
>> + }
>
> Just putting it here should work since it didn't get linked to the keyring if
> any errors occurred. Revoking it too shouldn't be necessary.
>
>> + key_invalidate(key);
>> + key_put(key);
>
> Why are you invalidating the user's key?
>
>> + keyref = lookup_user_key(id, 0, 0);
>
> KEY_NEED_SEARCH? Though I suppose it's not strictly necessary as it's a key
> that's private to the kernel.
>
>> + if (old_keyid != 0) {
>> + old_key = nvdimm_get_key(dev);
>> + if (old_key) {
>> + if (key_serial(old_key) != old_keyid) {
>
> Ummm... That's not what I meant. Given the permissions you've set on your
> private key, userspace shouldn't be able to find it, let alone give you the
> key ID.
>
> What I meant here was to use, say, nvdimm_lookup_user_key() to get a key from
> userspace that contains the old password. You can use the description of the
> key to search nvdimm_keyring for the private key and then compare the
> passwords.
Ok I have a bit of confusion here. When the user injects a new key with
the same description and new passphrase, would that not replace the
existing user key with the old passphrase? Also, if I'm calling
lookup_user_key, where would the key_id come from for the old user key?
I suppose I can cache it.... Maybe I'm not quite understanding the exact
flow of how things you are suggesting.
>
> Then you don't need to passphrases in the new key.
>
>> + rc = nvdimm_check_key_len(key->datalen, update);
>
> payload->datalen.
>
>> + down_read(&key->sem);
>
> This needs to be earlier. The payload attached to the new key can be replaced
> by keyctl_update() at any time whilst you're not holding the lock, so you
> cannot use key->payload[*] without holding the lock or the RCU read lock.
>
>> + if (update)
>> + key_invalidate(key);
>
> The key doesn't belong to you - should you really be invalidating it?
>
>> + else {
>> + key_link(nvdimm_keyring, key);
>> + nvdimm->key = key;
>> + key->perm |= KEY_USR_SEARCH;
>> + }
>
> Um - do you really want to be taking the key into your internal keyring? Why
> aren't you calling nvdimm_replace_key()? Also, you shouldn't alter the
> permission - it's not your key.
>
>> +static int __parse_update(const char *buf, size_t len, unsigned int *old_id,
>> + unsigned int *new_id)
>> +{
>
> Try using sscanf()?
>
> David
>
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next prev parent reply other threads:[~2018-09-22 0:25 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-28 22:47 [PATCH v8 00/12] Adding security support for nvdimm Dave Jiang
2018-08-28 22:47 ` [PATCH v8 01/12] nfit: add support for Intel DSM 1.7 commands Dave Jiang
2018-08-28 22:47 ` [PATCH v8 02/12] libnvdimm: create keyring to store security keys Dave Jiang
2018-09-22 0:19 ` Dan Williams
2018-09-24 21:04 ` David Howells
2018-09-24 21:12 ` Dave Jiang
2018-08-28 22:47 ` [PATCH v8 03/12] nfit/libnvdimm: store dimm id as a member to struct nvdimm Dave Jiang
2018-08-28 22:47 ` [PATCH v8 04/12] keys: export lookup_user_key to external users Dave Jiang
2018-09-21 21:59 ` Dan Williams
2018-09-21 22:02 ` Dave Jiang
2018-09-21 23:05 ` David Howells
2018-08-28 22:47 ` [PATCH v8 05/12] nfit/libnvdimm: add unlock of nvdimm support for Intel DIMMs Dave Jiang
2018-09-23 0:10 ` Dan Williams
2018-08-28 22:47 ` [PATCH v8 06/12] nfit/libnvdimm: add set passphrase support for Intel nvdimms Dave Jiang
2018-08-28 22:47 ` [PATCH v8 07/12] nfit/libnvdimm: add disable passphrase support to Intel nvdimm Dave Jiang
2018-08-28 22:48 ` [PATCH v8 08/12] nfit/libnvdimm: add freeze security " Dave Jiang
2018-08-28 22:48 ` [PATCH v8 09/12] nfit/libnvdimm: add support for issue secure erase DSM " Dave Jiang
2018-08-28 22:48 ` [PATCH v8 10/12] nfit_test: add context to dimm_dev for nfit_test Dave Jiang
2018-08-28 22:48 ` [PATCH v8 11/12] nfit_test: add test support for Intel nvdimm security DSMs Dave Jiang
2018-08-28 22:48 ` [PATCH v8 12/12] libnvdimm: add documentation for nvdimm security support Dave Jiang
2018-09-21 23:07 ` [PATCH v8 02/12] libnvdimm: create keyring to store security keys David Howells
2018-09-21 23:20 ` [PATCH v8 05/12] nfit/libnvdimm: add unlock of nvdimm support for Intel DIMMs David Howells
2018-09-21 23:27 ` Dave Jiang
2018-09-21 23:51 ` Dan Williams
2018-09-21 23:57 ` [PATCH v8 06/12] nfit/libnvdimm: add set passphrase support for Intel nvdimms David Howells
2018-09-22 0:25 ` Dave Jiang [this message]
2018-09-22 1:26 ` Dan Williams
2018-09-22 0:01 ` [PATCH v8 04/12] keys: export lookup_user_key to external users David Howells
2018-09-24 21:02 ` [PATCH v8 02/12] libnvdimm: create keyring to store security keys David Howells
2018-09-24 21:15 ` Dave Jiang
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