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List:       linux-keyrings
Subject:    Re: [PATCH v1 2/2] asymmetric_keys: log on fatal failures in PE/pkcs7
From:       Jarkko Sakkinen <jarkko () kernel ! org>
Date:       2023-02-17 21:14:00
Message-ID: Y+/uGG1rsvf9kt4d () kernel ! org
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On Fri, Feb 17, 2023 at 03:14:35PM -0500, Robbie Harwood wrote:
> These particular errors can be encountered while trying to kexec when
> secureboot lockdown is in place.  Without this change, even with a
> signed debug build, one still needs to reboot the machine to add the
> appropriate dyndbg parameters (since lockdown blocks debugfs).
> 
> Accordingly, upgrade all pr_debug() before fatal error into pr_info().
> 
> Signed-off-by: Robbie Harwood <rharwood@redhat.com>

Eessentially this changes configuration to hard coded implementation.

No gain IMHO. If you are ready to patch the kernel you could live with
boot time dyndbg parameters.

> ---
>  crypto/asymmetric_keys/pkcs7_verify.c  | 10 +++++-----
>  crypto/asymmetric_keys/verify_pefile.c | 24 ++++++++++++------------
>  2 files changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
> index f6321c785714..da425d142720 100644
> --- a/crypto/asymmetric_keys/pkcs7_verify.c
> +++ b/crypto/asymmetric_keys/pkcs7_verify.c
> @@ -79,16 +79,16 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
>  		}
>  
>  		if (sinfo->msgdigest_len != sig->digest_size) {
> -			pr_debug("Sig %u: Invalid digest size (%u)\n",
> -				 sinfo->index, sinfo->msgdigest_len);
> +			pr_info("Sig %u: Invalid digest size (%u)\n",
> +				sinfo->index, sinfo->msgdigest_len);
>  			ret = -EBADMSG;
>  			goto error;
>  		}
>  
>  		if (memcmp(sig->digest, sinfo->msgdigest,
>  			   sinfo->msgdigest_len) != 0) {
> -			pr_debug("Sig %u: Message digest doesn't match\n",
> -				 sinfo->index);
> +			pr_info("Sig %u: Message digest doesn't match\n",
> +				sinfo->index);
>  			ret = -EKEYREJECTED;
>  			goto error;
>  		}
> @@ -478,7 +478,7 @@ int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7,
>  			       const void *data, size_t datalen)
>  {
>  	if (pkcs7->data) {
> -		pr_debug("Data already supplied\n");
> +		pr_info("Data already supplied\n");
>  		return -EINVAL;
>  	}
>  	pkcs7->data = data;
> diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c
> index fe1bb374239d..c30e6610db26 100644
> --- a/crypto/asymmetric_keys/verify_pefile.c
> +++ b/crypto/asymmetric_keys/verify_pefile.c
> @@ -74,7 +74,7 @@ static int pefile_parse_binary(const void *pebuf, unsigned int pelen,
>  		break;
>  
>  	default:
> -		pr_debug("Unknown PEOPT magic = %04hx\n", pe32->magic);
> +		pr_info("Unknown PEOPT magic = %04hx\n", pe32->magic);
>  		return -ELIBBAD;
>  	}
>  
> @@ -95,7 +95,7 @@ static int pefile_parse_binary(const void *pebuf, unsigned int pelen,
>  	ctx->certs_size = ddir->certs.size;
>  
>  	if (!ddir->certs.virtual_address || !ddir->certs.size) {
> -		pr_debug("Unsigned PE binary\n");
> +		pr_info("Unsigned PE binary\n");
>  		return -ENODATA;
>  	}
>  
> @@ -127,7 +127,7 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
>  	unsigned len;
>  
>  	if (ctx->sig_len < sizeof(wrapper)) {
> -		pr_debug("Signature wrapper too short\n");
> +		pr_info("Signature wrapper too short\n");
>  		return -ELIBBAD;
>  	}
>  
> @@ -142,16 +142,16 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
>  	 * rounded up since 0.110.
>  	 */
>  	if (wrapper.length > ctx->sig_len) {
> -		pr_debug("Signature wrapper bigger than sig len (%x > %x)\n",
> -			 ctx->sig_len, wrapper.length);
> +		pr_info("Signature wrapper bigger than sig len (%x > %x)\n",
> +			ctx->sig_len, wrapper.length);
>  		return -ELIBBAD;
>  	}
>  	if (wrapper.revision != WIN_CERT_REVISION_2_0) {
> -		pr_debug("Signature is not revision 2.0\n");
> +		pr_info("Signature is not revision 2.0\n");
>  		return -ENOTSUPP;
>  	}
>  	if (wrapper.cert_type != WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
> -		pr_debug("Signature certificate type is not PKCS\n");
> +		pr_info("Signature certificate type is not PKCS\n");
>  		return -ENOTSUPP;
>  	}
>  
> @@ -164,7 +164,7 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
>  	ctx->sig_offset += sizeof(wrapper);
>  	ctx->sig_len -= sizeof(wrapper);
>  	if (ctx->sig_len < 4) {
> -		pr_debug("Signature data missing\n");
> +		pr_info("Signature data missing\n");
>  		return -EKEYREJECTED;
>  	}
>  
> @@ -198,7 +198,7 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
>  		return 0;
>  	}
>  not_pkcs7:
> -	pr_debug("Signature data not PKCS#7\n");
> +	pr_info("Signature data not PKCS#7\n");
>  	return -ELIBBAD;
>  }
>  
> @@ -341,8 +341,8 @@ static int pefile_digest_pe(const void *pebuf, unsigned int pelen,
>  	digest_size = crypto_shash_digestsize(tfm);
>  
>  	if (digest_size != ctx->digest_len) {
> -		pr_debug("Digest size mismatch (%zx != %x)\n",
> -			 digest_size, ctx->digest_len);
> +		pr_info("Digest size mismatch (%zx != %x)\n",
> +			digest_size, ctx->digest_len);
>  		ret = -EBADMSG;
>  		goto error_no_desc;
>  	}
> @@ -373,7 +373,7 @@ static int pefile_digest_pe(const void *pebuf, unsigned int pelen,
>  	 * PKCS#7 certificate.
>  	 */
>  	if (memcmp(digest, ctx->digest, ctx->digest_len) != 0) {
> -		pr_debug("Digest mismatch\n");
> +		pr_info("Digest mismatch\n");
>  		ret = -EKEYREJECTED;
>  	} else {
>  		pr_debug("The digests match!\n");
> -- 
> 2.39.1
> 

BR, Jarkko
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