certs: Explain the rationale to call panic()

The blacklist_init() function calls panic() for memory allocation
errors.  This change documents the reason why we don't return -ENODEV.

Link: https://lore.kernel.org/r/20220322111323.542184-2-mic@digikod.net
Link: https://lore.kernel.org/r/YjeW2r6Wv55Du0bJ@iki.fi
Suggested-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
This commit is contained in:
Mickaël Salaün 2022-03-22 12:13:23 +01:00 committed by Jarkko Sakkinen
parent 6364d106e0
commit 4d99750106

View File

@ -307,6 +307,15 @@ static int restrict_link_for_blacklist(struct key *dest_keyring,
/*
* Initialise the blacklist
*
* The blacklist_init() function is registered as an initcall via
* device_initcall(). As a result if the blacklist_init() function fails for
* any reason the kernel continues to execute. While cleanly returning -ENODEV
* could be acceptable for some non-critical kernel parts, if the blacklist
* keyring fails to load it defeats the certificate/key based deny list for
* signed modules. If a critical piece of security functionality that users
* expect to be present fails to initialize, panic()ing is likely the right
* thing to do.
*/
static int __init blacklist_init(void)
{