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KEYS: Merge the type-specific data with the payload data

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Merge the type-specific data with the payload data into one four-word chunk
as it seems pointless to keep them separate.

Use user_key_payload() for accessing the payloads of overloaded
user-defined keys.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
cc: ecryptfs@vger.kernel.org
cc: linux-ext4@vger.kernel.org
cc: linux-f2fs-devel@lists.sourceforge.net
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-ima-devel@lists.sourceforge.net
This commit is contained in:
David Howells 2015-10-21 14:04:48 +01:00
parent 4adc605edc
commit 146aa8b145
49 changed files with 286 additions and 230 deletions
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41
Documentation/security/keys.txt
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@ -1049,12 +1049,12 @@ search a specific keyring, so using keyrings in this way is of limited utility.
NOTES ON ACCESSING PAYLOAD CONTENTS
===================================
The simplest payload is just a number in key->payload.value. In this case,
there's no need to indulge in RCU or locking when accessing the payload.
The simplest payload is just data stored in key->payload directly. In this
case, there's no need to indulge in RCU or locking when accessing the payload.
More complex payload contents must be allocated and a pointer to them set in
key->payload.data. One of the following ways must be selected to access the
data:
More complex payload contents must be allocated and pointers to them set in the
key->payload.data[] array. One of the following ways must be selected to
access the data:
(1) Unmodifiable key type.
@ -1092,6 +1092,13 @@ data:
the payload. key->datalen cannot be relied upon to be consistent with the
payload just dereferenced if the key's semaphore is not held.
Note that key->payload.data[0] has a shadow that is marked for __rcu
usage. This is called key->payload.rcu_data0. The following accessors
wrap the RCU calls to this element:
rcu_assign_keypointer(struct key *key, void *data);
void *rcu_dereference_key(struct key *key);
===================
DEFINING A KEY TYPE
@ -1143,8 +1150,7 @@ The structure has a number of fields, some of which are mandatory:
struct key_preparsed_payload {
char *description;
void *type_data[2];
void *payload;
union key_payload payload;
const void *data;
size_t datalen;
size_t quotalen;
@ -1160,10 +1166,9 @@ The structure has a number of fields, some of which are mandatory:
attached as a string to the description field. This will be used for the
key description if the caller of add_key() passes NULL or "".
The method can attach anything it likes to type_data[] and payload. These
are merely passed along to the instantiate() or update() operations. If
set, the expiry time will be applied to the key if it is instantiated from
this data.
The method can attach anything it likes to payload. This is merely passed
along to the instantiate() or update() operations. If set, the expiry
time will be applied to the key if it is instantiated from this data.
The method should return 0 if successful or a negative error code
otherwise.
@ -1172,11 +1177,10 @@ The structure has a number of fields, some of which are mandatory:
(*) void (*free_preparse)(struct key_preparsed_payload *prep);
This method is only required if the preparse() method is provided,
otherwise it is unused. It cleans up anything attached to the
description, type_data and payload fields of the key_preparsed_payload
struct as filled in by the preparse() method. It will always be called
after preparse() returns successfully, even if instantiate() or update()
succeed.
otherwise it is unused. It cleans up anything attached to the description
and payload fields of the key_preparsed_payload struct as filled in by the
preparse() method. It will always be called after preparse() returns
successfully, even if instantiate() or update() succeed.
(*) int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
@ -1197,6 +1201,11 @@ The structure has a number of fields, some of which are mandatory:
It is safe to sleep in this method.
generic_key_instantiate() is provided to simply copy the data from
prep->payload.data[] to key->payload.data[], with RCU-safe assignment on
the first element. It will then clear prep->payload.data[] so that the
free_preparse method doesn't release the data.
(*) int (*update)(struct key *key, const void *data, size_t datalen);