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authorHerbert Xu <herbert@gondor.apana.org.au>2019-12-18 15:53:01 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2019-12-27 18:18:03 +0800
commit5f567fffaae995dce3498e175e47d5a779fb0270 (patch)
tree5c9d1ea0730f324296ef35af028bbd1042c066e6 /crypto/algapi.c
parentcrypto: sun4i-ss - make unexported sun4i_ss_pm_ops static (diff)
downloadlinux-dev-5f567fffaae995dce3498e175e47d5a779fb0270.tar.xz
linux-dev-5f567fffaae995dce3498e175e47d5a779fb0270.zip
crypto: api - Retain alg refcount in crypto_grab_spawn
This patch changes crypto_grab_spawn to retain the reference count on the algorithm. This is because the caller needs to access the algorithm parameters and without the reference count the algorithm can be freed at any time. The reference count will be subsequently dropped by the crypto API once the instance has been registered. The helper crypto_drop_spawn will also conditionally drop the reference count depending on whether it has been registered. Note that the code is actually added to crypto_init_spawn. However, unless the caller activates this by setting spawn->dropref beforehand then nothing happens. The only caller that sets dropref is currently crypto_grab_spawn. Once all legacy users of crypto_init_spawn disappear, then we can kill the dropref flag. Internally each instance will maintain a list of its spawns prior to registration. This memory used by this list is shared with other fields that are only used after registration. In order for this to work a new flag spawn->registered is added to indicate whether spawn->inst can be used. Fixes: d6ef2f198d4c ("crypto: api - Add crypto_grab_spawn primitive") Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to '')
-rw-r--r--crypto/algapi.c48
1 files changed, 40 insertions, 8 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c
index fe57b4f696ac..363849983941 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -124,8 +124,6 @@ static void crypto_remove_instance(struct crypto_instance *inst,
return;
inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
- if (hlist_unhashed(&inst->list))
- return;
if (!tmpl || !crypto_tmpl_get(tmpl))
return;
@@ -175,17 +173,26 @@ void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list,
list);
inst = spawn->inst;
- BUG_ON(&inst->alg == alg);
-
list_move(&spawn->list, &stack);
+ spawn->dead = !spawn->registered || &inst->alg != nalg;
+
+ if (!spawn->registered)
+ break;
+
+ BUG_ON(&inst->alg == alg);
if (&inst->alg == nalg)
break;
- spawn->dead = true;
spawns = &inst->alg.cra_users;
/*
+ * Even if spawn->registered is true, the
+ * instance itself may still be unregistered.
+ * This is because it may have failed during
+ * registration. Therefore we still need to
+ * make the following test.
+ *
* We may encounter an unregistered instance here, since
* an instance's spawns are set up prior to the instance
* being registered. An unregistered instance will have
@@ -208,7 +215,7 @@ void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list,
list_for_each_entry_safe(spawn, n, &secondary_spawns, list) {
if (!spawn->dead)
list_move(&spawn->list, &spawn->alg->cra_users);
- else
+ else if (spawn->registered)
crypto_remove_instance(spawn->inst, list);
}
}
@@ -599,6 +606,7 @@ int crypto_register_instance(struct crypto_template *tmpl,
struct crypto_instance *inst)
{
struct crypto_larval *larval;
+ struct crypto_spawn *spawn;
int err;
err = crypto_check_alg(&inst->alg);
@@ -610,6 +618,23 @@ int crypto_register_instance(struct crypto_template *tmpl,
down_write(&crypto_alg_sem);
+ larval = ERR_PTR(-EAGAIN);
+ for (spawn = inst->spawns; spawn;) {
+ struct crypto_spawn *next;
+
+ if (spawn->dead)
+ goto unlock;
+
+ next = spawn->next;
+ spawn->inst = inst;
+ spawn->registered = true;
+
+ if (spawn->dropref)
+ crypto_mod_put(spawn->alg);
+
+ spawn = next;
+ }
+
larval = __crypto_register_alg(&inst->alg);
if (IS_ERR(larval))
goto unlock;
@@ -655,7 +680,9 @@ int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
if (WARN_ON_ONCE(inst == NULL))
return -EINVAL;
- spawn->inst = inst;
+ spawn->next = inst->spawns;
+ inst->spawns = spawn;
+
spawn->mask = mask;
down_write(&crypto_alg_sem);
@@ -697,8 +724,10 @@ int crypto_grab_spawn(struct crypto_spawn *spawn, const char *name,
if (IS_ERR(alg))
return PTR_ERR(alg);
+ spawn->dropref = true;
err = crypto_init_spawn(spawn, alg, spawn->inst, mask);
- crypto_mod_put(alg);
+ if (err)
+ crypto_mod_put(alg);
return err;
}
EXPORT_SYMBOL_GPL(crypto_grab_spawn);
@@ -709,6 +738,9 @@ void crypto_drop_spawn(struct crypto_spawn *spawn)
if (!spawn->dead)
list_del(&spawn->list);
up_write(&crypto_alg_sem);
+
+ if (spawn->dropref && !spawn->registered)
+ crypto_mod_put(spawn->alg);
}
EXPORT_SYMBOL_GPL(crypto_drop_spawn);