Re: [PATCH v7 2/3] ima-evm-utils: Allow manual setting keyid from a cert file

[Mimi Zohar <zohar@linux.ibm.com>]

Hi Vitaly,

On Thu, 2021-07-01 at 04:13 +0300, Vitaly Chikunov wrote:

> @@ -2805,6 +2811,14 @@ int main(int argc, char *argv[])
>  			}
>  			imaevm_params.keyid = keyid;
>  			break;
> +		case 145:
> +			keyid = imaevm_read_keyid(optarg);
> +			if (keyid == 0) {

The function comment indicates zero is returned on error, which is
normally true, but -1 is returned to indicate reading the cert failed. 

> +				log_err("Error reading keyid.\n");
> +				exit(1);
> +			}
> +			imaevm_params.keyid = keyid;

As a result, imaevm_params.keyid is set to -1, which the "--keyid="
case would detect, but isn't detected here.

> +			break;
>  		case '?':
>  			exit(1);
>  			break;
> diff --git a/src/imaevm.h b/src/imaevm.h
> index fe244f1..491f136 100644
> --- a/src/imaevm.h
> +++ b/src/imaevm.h
> 
> +/**

kernel doc?  :)

> + * imaevm_read_keyid() - Read 32-bit keyid from the cert file
> + * @certfile:	File with certificate in PEM or DER form.
> + *
> + * Try to read keyid from Subject Key Identifier (SKID) of x509 certificate.
> + * Autodetect if cert is in PEM (tried first) or DER encoding.
> + *
> + * Return: 0 on error, logged error message;
> + *         32-bit keyid in host order.

As mentioned above, -1 could be returned.

> + */
> +uint32_t imaevm_read_keyid(const char *certfile)
> +{
> +	uint32_t keyid_be = 0;
> +	X509 *x;
> +
> +	/* true: to load in DER form too. */
> +	if (!(x = read_cert(certfile, true)))
> +		return -1;
> +	extract_keyid(&keyid_be, x, certfile);
> +	/* On error keyid_be will not be set, returning 0. */

Ok

thanks,

Mimi

> +	X509_free(x);
> +	return ntohl(keyid_be);
> +}
> +
>  static EVP_PKEY *read_priv_pkey(const char *keyfile, const char *keypass)
>  {
>  	FILE *fp;