linux-kernel - Re: [PATCH] KEYS: Make use of platform keyring for module signature verify

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Date:   Wed, 24 Apr 2019 06:35:02 +1000 (AEST)
From:   James Morris <jmorris@...ei.org>
To:     Robert Holmes <robeholmes@...il.com>
cc:     jeyu@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KEYS: Make use of platform keyring for module signature
 verify

On Tue, 23 Apr 2019, Robert Holmes wrote:

> This patch completes commit 278311e417be ("kexec, KEYS: Make use of
> platform keyring for signature verify") which, while adding the
> platform keyring for bzImage verification, neglected to also add
> this keyring for module verification.
> 

You should most likely add the keyrings list to the cc: for these kinds of 
patches.

> As such, kernel modules signed with keys from the MokList variable
> were not successfully verified.
> 
> Signed-off-by: Robert Holmes <robeholmes@...il.com>
> ---
>  kernel/module_signing.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/module_signing.c b/kernel/module_signing.c
> index 6b9a926fd86b..cf94220e9154 100644
> --- a/kernel/module_signing.c
> +++ b/kernel/module_signing.c
> @@ -49,6 +49,7 @@ int mod_verify_sig(const void *mod, struct load_info *info)
>  {
>  	struct module_signature ms;
>  	size_t sig_len, modlen = info->len;
> +	int ret;
>  
>  	pr_devel("==>%s(,%zu)\n", __func__, modlen);
>  
> @@ -82,8 +83,15 @@ int mod_verify_sig(const void *mod, struct load_info *info)
>  		return -EBADMSG;
>  	}
>  
> -	return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
> -				      VERIFY_USE_SECONDARY_KEYRING,
> -				      VERIFYING_MODULE_SIGNATURE,
> -				      NULL, NULL);
> +	ret = verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
> +				     VERIFY_USE_SECONDARY_KEYRING,
> +				     VERIFYING_MODULE_SIGNATURE,
> +				     NULL, NULL);
> +	if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
> +		ret = verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
> +					     VERIFY_USE_PLATFORM_KEYRING,
> +					     VERIFYING_MODULE_SIGNATURE,
> +					     NULL, NULL);
> +	}
> +	return ret;
>  }
> 

-- 
James Morris
<jmorris@...ei.org>