Re: [PATCH] ima: require signed IMA policy when UEFI secure boot is enabled

From: Mimi Zohar
Date: Tue Jul 04 2023 - 08:57:31 EST


On Mon, 2023-07-03 at 19:54 +0800, Coiby Xu wrote:
> With the introduction of the .machine keyring for UEFI-based systems,
> users are able to add custom CAs keys via MOK. This allow users to sign
> their own IMA polices. For the sake of security, mandate signed IMA
> policy when UEFI secure boot is enabled.
>
> Suggested-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx>
> ---
> security/integrity/ima/ima_efi.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/security/integrity/ima/ima_efi.c b/security/integrity/ima/ima_efi.c
> index 9db66fe310d4..bb2881759505 100644
> --- a/security/integrity/ima/ima_efi.c
> +++ b/security/integrity/ima/ima_efi.c
> @@ -58,6 +58,9 @@ static const char * const sb_arch_rules[] = {
> #if !IS_ENABLED(CONFIG_MODULE_SIG)
> "appraise func=MODULE_CHECK appraise_type=imasig",
> #endif
> +#if IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING) && IS_ENABLED(CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY)
> + "appraise func=POLICY_CHECK appraise_type=imasig",
> +#endif /* CONFIG_INTEGRITY_MACHINE_KEYRING && IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY */
> "measure func=MODULE_CHECK",
> NULL
> };

Thanks, Coiby.

Using IS_ENABLED() is not wrong, but unnecessary. IS_BUILTIN()
suffices.

--
thanks,

Mimi