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keys: Move the RCU locks outwards from the keyring search functions

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Move the RCU locks outwards from the keyring search functions so that it
will become possible to provide an RCU-capable partial request_key()
function in a later commit.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells
2019-06-19 16:10:15 +01:00
parent a09003b5d7
commit e59428f721
8 changed files with 77 additions and 61 deletions
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60
security/keys/request_key_auth.c
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@@ -58,7 +58,7 @@ static void request_key_auth_free_preparse(struct key_preparsed_payload *prep)
static int request_key_auth_instantiate(struct key *key,
struct key_preparsed_payload *prep)
{
key->payload.data[0] = (struct request_key_auth *)prep->data;
rcu_assign_keypointer(key, (struct request_key_auth *)prep->data);
return 0;
}
@@ -68,7 +68,7 @@ static int request_key_auth_instantiate(struct key *key,
static void request_key_auth_describe(const struct key *key,
struct seq_file *m)
{
struct request_key_auth *rka = get_request_key_auth(key);
struct request_key_auth *rka = dereference_key_rcu(key);
seq_puts(m, "key:");
seq_puts(m, key->description);
@@ -83,7 +83,7 @@ static void request_key_auth_describe(const struct key *key,
static long request_key_auth_read(const struct key *key,
char __user *buffer, size_t buflen)
{
struct request_key_auth *rka = get_request_key_auth(key);
struct request_key_auth *rka = dereference_key_locked(key);
size_t datalen;
long ret;
@@ -102,23 +102,6 @@ static long request_key_auth_read(const struct key *key,
return ret;
}
/*
* Handle revocation of an authorisation token key.
*
* Called with the key sem write-locked.
*/
static void request_key_auth_revoke(struct key *key)
{
struct request_key_auth *rka = get_request_key_auth(key);
kenter("{%d}", key->serial);
if (rka->cred) {
put_cred(rka->cred);
rka->cred = NULL;
}
}
static void free_request_key_auth(struct request_key_auth *rka)
{
if (!rka)
@@ -131,16 +114,43 @@ static void free_request_key_auth(struct request_key_auth *rka)
kfree(rka);
}
/*
* Dispose of the request_key_auth record under RCU conditions
*/
static void request_key_auth_rcu_disposal(struct rcu_head *rcu)
{
struct request_key_auth *rka =
container_of(rcu, struct request_key_auth, rcu);
free_request_key_auth(rka);
}
/*
* Handle revocation of an authorisation token key.
*
* Called with the key sem write-locked.
*/
static void request_key_auth_revoke(struct key *key)
{
struct request_key_auth *rka = dereference_key_locked(key);
kenter("{%d}", key->serial);
rcu_assign_keypointer(key, NULL);
call_rcu(&rka->rcu, request_key_auth_rcu_disposal);
}
/*
* Destroy an instantiation authorisation token key.
*/
static void request_key_auth_destroy(struct key *key)
{
struct request_key_auth *rka = get_request_key_auth(key);
struct request_key_auth *rka = rcu_access_pointer(key->payload.rcu_data0);
kenter("{%d}", key->serial);
free_request_key_auth(rka);
if (rka) {
rcu_assign_keypointer(key, NULL);
call_rcu(&rka->rcu, request_key_auth_rcu_disposal);
}
}
/*
@@ -249,7 +259,9 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id)
ctx.index_key.desc_len = sprintf(description, "%x", target_id);
authkey_ref = search_process_keyrings(&ctx);
rcu_read_lock();
authkey_ref = search_process_keyrings_rcu(&ctx);
rcu_read_unlock();
if (IS_ERR(authkey_ref)) {
authkey = ERR_CAST(authkey_ref);