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From: David Howells <dhowells@redhat.com>
To: Dave Jiang <dave.jiang@intel.com>
Cc: alison.schofield@intel.com, keescook@chromium.org,
	linux-nvdimm@lists.01.org, ebiggers3@gmail.com,
	dhowells@redhat.com, keyrings@vger.kernel.org
Subject: Re: [PATCH v8 06/12] nfit/libnvdimm: add set passphrase support for Intel nvdimms
Date: Sat, 22 Sep 2018 00:57:16 +0100	[thread overview]
Message-ID: <19459.1537574236@warthog.procyon.org.uk> (raw)
In-Reply-To: <153549647177.4089.18112512093259339717.stgit@djiang5-desk3.ch.intel.com>

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.

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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  parent reply	other threads:[~2018-09-21 23:57 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 ` David Howells [this message]
2018-09-22  0:25   ` [PATCH v8 06/12] nfit/libnvdimm: add set passphrase support for Intel nvdimms Dave Jiang
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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