random: replace custom notifier chain with standard one
commit 5acd35487dc911541672b3ffc322851769c32a56 upstream.
We previously rolled our own randomness readiness notifier, which only
has two users in the whole kernel. Replace this with a more standard
atomic notifier block that serves the same purpose with less code. Also
unexport the symbols, because no modules use it, only unconditional
builtins. The only drawback is that it's possible for a notification
handler returning the "stop" code to prevent further processing, but
given that there are only two users, and that we're unexporting this
anyway, that doesn't seem like a significant drawback for the
simplification we receive here.
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Theodore Ts'o <[email protected]>
Reviewed-by: Dominik Brodowski <[email protected]>
[Jason: for stable, also backported to crypto/drbg.c, not unexporting.]
Signed-off-by: Jason A. Donenfeld <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
diff --git a/crypto/drbg.c b/crypto/drbg.c
index 3132967..19ea8d6 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1490,12 +1490,13 @@ static int drbg_generate_long(struct drbg_state *drbg,
return 0;
}
-static void drbg_schedule_async_seed(struct random_ready_callback *rdy)
+static int drbg_schedule_async_seed(struct notifier_block *nb, unsigned long action, void *data)
{
- struct drbg_state *drbg = container_of(rdy, struct drbg_state,
+ struct drbg_state *drbg = container_of(nb, struct drbg_state,
random_ready);
schedule_work(&drbg->seed_work);
+ return 0;
}
static int drbg_prepare_hrng(struct drbg_state *drbg)
@@ -1510,10 +1511,8 @@ static int drbg_prepare_hrng(struct drbg_state *drbg)
INIT_WORK(&drbg->seed_work, drbg_async_seed);
- drbg->random_ready.owner = THIS_MODULE;
- drbg->random_ready.func = drbg_schedule_async_seed;
-
- err = add_random_ready_callback(&drbg->random_ready);
+ drbg->random_ready.notifier_call = drbg_schedule_async_seed;
+ err = register_random_ready_notifier(&drbg->random_ready);
switch (err) {
case 0:
@@ -1524,7 +1523,7 @@ static int drbg_prepare_hrng(struct drbg_state *drbg)
fallthrough;
default:
- drbg->random_ready.func = NULL;
+ drbg->random_ready.notifier_call = NULL;
return err;
}
@@ -1628,8 +1627,8 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
*/
static int drbg_uninstantiate(struct drbg_state *drbg)
{
- if (drbg->random_ready.func) {
- del_random_ready_callback(&drbg->random_ready);
+ if (drbg->random_ready.notifier_call) {
+ unregister_random_ready_notifier(&drbg->random_ready);
cancel_work_sync(&drbg->seed_work);
}
