[RFC PATCH v3 02/13] certs: Introduce ability to link to a system key

[Jarkko Sakkinen]

On Thu, 2024-10-17 at 09:55 -0600, Eric Snowberg wrote:
> Introduce system_key_link(), a new function to allow a keyring to
> link
> to a key contained within one of the system keyrings (builtin,
> secondary,
> or platform). Depending on how the kernel is built, if the machine
> keyring is available, it will be checked as well, since it is linked
> to
> the secondary keyring. If the asymmetric key id matches a key within
> one
> of these system keyrings, the matching key is linked into the passed
> in
> keyring.
> 
> Signed-off-by: Eric Snowberg <eric.snowberg at oracle.com>
> ---
>  certs/system_keyring.c        | 30 ++++++++++++++++++++++++++++++
>  include/keys/system_keyring.h |  7 ++++++-
>  2 files changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/certs/system_keyring.c b/certs/system_keyring.c
> index e344cee10d28..4abee7514442 100644
> --- a/certs/system_keyring.c
> +++ b/certs/system_keyring.c
> @@ -20,6 +20,9 @@
>  static struct key *builtin_trusted_keys;
>  #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
>  static struct key *secondary_trusted_keys;

/*
 * Explain system_trusted_keys (nothing too detailed, only the gist)
 */

> +#define system_trusted_keys secondary_trusted_keys
> +#else
> +#define system_trusted_keys builtin_trusted_keys
>  #endif
>  #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
>  static struct key *machine_trusted_keys;

We have enough these to make this quite convoluted so let's put some
helpful reminders. I would forget this in no time ;-) So if it comes
down to that, please put something because I have a goldfish memory.

BR, Jarkko