linux-kernel - Re: [PATCH v3 02/11] evm: Load EVM key in ima_load

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Message-ID: <58c23338f15ea13278f275832ac35eeff875daad.camel@linux.ibm.com>
Date:   Mon, 01 Mar 2021 13:06:31 -0500
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     Roberto Sassu <roberto.sassu@...wei.com>, mjg59@...gle.com
Cc:     linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        silviu.vlasceanu@...wei.com
Subject: Re: [PATCH v3 02/11] evm: Load EVM key in ima_load_x509() to avoid
 appraisal

Hi Roberto,

On Wed, 2020-11-11 at 10:22 +0100, Roberto Sassu wrote:
> Public keys do not need to be appraised by IMA as the restriction on the
> IMA/EVM keyrings ensures that a key can be loaded only if it is signed with
> a key in the primary or secondary keyring.
> 
> However, when evm_load_x509() is called, appraisal is already enabled and
> a valid IMA signature must be added to the EVM key to pass verification.
> 
> Since the restriction is applied on both IMA and EVM keyrings, it is safe
> to disable appraisal also when the EVM key is loaded. This patch calls
> evm_load_x509() inside ima_load_x509() if CONFIG_IMA_LOAD_X509 is defined.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@...wei.com>
> Reviewed-by: Mimi Zohar <zohar@...ux.ibm.com>
> ---
>  security/integrity/iint.c         | 2 ++
>  security/integrity/ima/ima_init.c | 4 ++++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/security/integrity/iint.c b/security/integrity/iint.c
> index 1d20003243c3..7d08c31c612f 100644
> --- a/security/integrity/iint.c
> +++ b/security/integrity/iint.c
> @@ -200,7 +200,9 @@ int integrity_kernel_read(struct file *file, loff_t offset,
>  void __init integrity_load_keys(void)
>  {
>  	ima_load_x509();
> +#ifndef CONFIG_IMA_LOAD_X509
>  	evm_load_x509();
> +#endif

Please replace the ifdef with the IS_ENABLED() equivalent.

thanks,

Mimi