[PATCH 4/9] KEYS: Allow expiry time to be set when preparsing a key

From: David Howells
Date: Mon Nov 04 2013 - 13:22:36 EST


Allow a key type's preparsing routine to set the expiry time for a key.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

Documentation/security/keys.txt | 10 +++++++---
include/linux/key-type.h | 1 +
security/keys/key.c | 8 ++++++++
3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt
index a4c33f1a7c6d..315cf96a41a2 100644
--- a/Documentation/security/keys.txt
+++ b/Documentation/security/keys.txt
@@ -1150,20 +1150,24 @@ The structure has a number of fields, some of which are mandatory:
const void *data;
size_t datalen;
size_t quotalen;
+ time_t expiry;
};

Before calling the method, the caller will fill in data and datalen with
the payload blob parameters; quotalen will be filled in with the default
- quota size from the key type and the rest will be cleared.
+ quota size from the key type; expiry will be set to TIME_T_MAX and the
+ rest will be cleared.

If a description can be proposed from the payload contents, that should be
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.
+ 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 should return 0 if success ful or a negative error code
+ The method should return 0 if successful or a negative error code
otherwise.


diff --git a/include/linux/key-type.h b/include/linux/key-type.h
index d2b4845d74bf..44792ee649de 100644
--- a/include/linux/key-type.h
+++ b/include/linux/key-type.h
@@ -45,6 +45,7 @@ struct key_preparsed_payload {
const void *data; /* Raw data */
size_t datalen; /* Raw datalen */
size_t quotalen; /* Quota length for proposed payload */
+ time_t expiry; /* Expiry time of key */
bool trusted; /* True if key is trusted */
};

diff --git a/security/keys/key.c b/security/keys/key.c
index 64dc9cf6848e..1af0edacd804 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -443,6 +443,11 @@ static int __key_instantiate_and_link(struct key *key,
/* disable the authorisation key */
if (authkey)
key_revoke(authkey);
+
+ if (prep->expiry != TIME_T_MAX) {
+ key->expiry = prep->expiry;
+ key_schedule_gc(prep->expiry + key_gc_delay);
+ }
}
}

@@ -485,6 +490,7 @@ int key_instantiate_and_link(struct key *key,
prep.data = data;
prep.datalen = datalen;
prep.quotalen = key->type->def_datalen;
+ prep.expiry = TIME_T_MAX;
if (key->type->preparse) {
ret = key->type->preparse(&prep);
if (ret < 0)
@@ -817,6 +823,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
prep.datalen = plen;
prep.quotalen = index_key.type->def_datalen;
prep.trusted = flags & KEY_ALLOC_TRUSTED;
+ prep.expiry = TIME_T_MAX;
if (index_key.type->preparse) {
ret = index_key.type->preparse(&prep);
if (ret < 0) {
@@ -947,6 +954,7 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen)
prep.data = payload;
prep.datalen = plen;
prep.quotalen = key->type->def_datalen;
+ prep.expiry = TIME_T_MAX;
if (key->type->preparse) {
ret = key->type->preparse(&prep);
if (ret < 0)

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