[PATCH] KEYS: trusted: Rollback init_trusted() consistently

[Sumit Garg]

On Wed, 11 Oct 2023 at 04:46, Jarkko Sakkinen <jarkko at kernel.org> wrote:
>
> Do bind neither static calls nor trusted_key_exit() before a successful
> init, in order to maintain a consistent state. In addition, depart the
> init_trusted() in the case of a real error (i.e. getting back something
> else than -ENODEV).
>
> Reported-by: Linus Torvalds <torvalds at linux-foundation.org>
> Closes: https://lore.kernel.org/linux-integrity/CAHk-=whOPoLaWM8S8GgoOPT7a2+nMH5h3TLKtn=R_3w4R1_Uvg@mail.gmail.com/
> Cc: stable at vger.kernel.org # v5.13+
> Fixes: 5d0682be3189 ("KEYS: trusted: Add generic trusted keys framework")
> Signed-off-by: Jarkko Sakkinen <jarkko at kernel.org>
> ---
>  security/keys/trusted-keys/trusted_core.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
> index 85fb5c22529a..fee1ab2c734d 100644
> --- a/security/keys/trusted-keys/trusted_core.c
> +++ b/security/keys/trusted-keys/trusted_core.c
> @@ -358,17 +358,17 @@ static int __init init_trusted(void)
>                 if (!get_random)
>                         get_random = kernel_get_random;
>
> -               static_call_update(trusted_key_seal,
> -                                  trusted_key_sources[i].ops->seal);
> -               static_call_update(trusted_key_unseal,
> -                                  trusted_key_sources[i].ops->unseal);
> -               static_call_update(trusted_key_get_random,
> -                                  get_random);
> -               trusted_key_exit = trusted_key_sources[i].ops->exit;
> -               migratable = trusted_key_sources[i].ops->migratable;
> -
>                 ret = trusted_key_sources[i].ops->init();
> -               if (!ret)
> +               if (!ret) {
> +                       static_call_update(trusted_key_seal, trusted_key_sources[i].ops->seal);
> +                       static_call_update(trusted_key_unseal, trusted_key_sources[i].ops->unseal);
> +                       static_call_update(trusted_key_get_random, get_random);
> +
> +                       trusted_key_exit = trusted_key_sources[i].ops->exit;
> +                       migratable = trusted_key_sources[i].ops->migratable;
> +               }
> +
> +               if (!ret || ret != -ENODEV)

As mentioned in the other thread, we should allow other trust sources
to be initialized if the primary one fails.

-Sumit

>                         break;
>         }
>
> --
> 2.39.2
>