diff options
| author | Jason A. Donenfeld | 2022-03-01 20:22:39 +0100 |
|---|---|---|
| committer | Jason A. Donenfeld | 2022-03-12 18:00:56 -0700 |
| commit | f3c2682bad7bc6033c837e9c66e5af881fe8d465 (patch) | |
| tree | f0101c73dee541fd4cd6e599e26f5e5b1195190e /drivers/char | |
| parent | 5acd35487dc911541672b3ffc322851769c32a56 (diff) | |
random: provide notifier for VM fork
Drivers such as WireGuard need to learn when VMs fork in order to clear
sessions. This commit provides a simple notifier_block for that, with a
register and unregister function. When no VM fork detection is compiled
in, this turns into a no-op, similar to how the power notifier works.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index aa7bc9a3a864..d9ca441c14bd 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1140,6 +1140,8 @@ void add_bootloader_randomness(const void *buf, size_t size) EXPORT_SYMBOL_GPL(add_bootloader_randomness); #if IS_ENABLED(CONFIG_VMGENID) +static BLOCKING_NOTIFIER_HEAD(vmfork_chain); + /* * Handle a new unique VM ID, which is unique, not secret, so we * don't credit it, but we do immediately force a reseed after so @@ -1152,10 +1154,23 @@ void add_vmfork_randomness(const void *unique_vm_id, size_t size) crng_reseed(true); pr_notice("crng reseeded due to virtual machine fork\n"); } + blocking_notifier_call_chain(&vmfork_chain, 0, NULL); } #if IS_MODULE(CONFIG_VMGENID) EXPORT_SYMBOL_GPL(add_vmfork_randomness); #endif + +int register_random_vmfork_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&vmfork_chain, nb); +} +EXPORT_SYMBOL_GPL(register_random_vmfork_notifier); + +int unregister_random_vmfork_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&vmfork_chain, nb); +} +EXPORT_SYMBOL_GPL(unregister_random_vmfork_notifier); #endif struct fast_pool { |