X.509: if signature is unsupported skip validation

[PATCH] X.509: if signature is unsupported skip validation

Posted by Thore Sommer 2 years, 4 months ago

When the hash algorithm for the signature is not available the digest size
is 0 and the signature in the certificate is marked as unsupported.

When validating a self-signed certificate, this needs to be checked,
because otherwise trying to validate the signature will fail with an
warning:

Loading compiled-in X.509 certificates
WARNING: CPU: 0 PID: 1 at crypto/rsa-pkcs1pad.c:537 \
pkcs1pad_verify+0x46/0x12c
...
Problem loading in-kernel X.509 certificate (-22)

Signed-off-by: Thore Sommer <public@thson.de>
---
 crypto/asymmetric_keys/x509_public_key.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 6fdfc82e23a8..7c71db3ac23d 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -130,6 +130,11 @@ int x509_check_for_self_signed(struct x509_certificate *cert)
 			goto out;
 	}
 
+	if (cert->unsupported_sig) {
+		ret = 0;
+		goto out;
+	}
+
 	ret = public_key_verify_signature(cert->pub, cert->sig);
 	if (ret < 0) {
 		if (ret == -ENOPKG) {
-- 
2.41.0

Re: [PATCH] X.509: if signature is unsupported skip validation

Posted by Herbert Xu 2 years, 3 months ago

On Tue, Aug 15, 2023 at 02:29:42PM +0300, Thore Sommer wrote:
> When the hash algorithm for the signature is not available the digest size
> is 0 and the signature in the certificate is marked as unsupported.
> 
> When validating a self-signed certificate, this needs to be checked,
> because otherwise trying to validate the signature will fail with an
> warning:
> 
> Loading compiled-in X.509 certificates
> WARNING: CPU: 0 PID: 1 at crypto/rsa-pkcs1pad.c:537 \
> pkcs1pad_verify+0x46/0x12c
> ...
> Problem loading in-kernel X.509 certificate (-22)
> 
> Signed-off-by: Thore Sommer <public@thson.de>
> ---
>  crypto/asymmetric_keys/x509_public_key.c | 5 +++++
>  1 file changed, 5 insertions(+)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH] X.509: if signature is unsupported skip validation

Posted by Jarkko Sakkinen 2 years, 4 months ago

On Tue Aug 15, 2023 at 2:29 PM EEST, Thore Sommer wrote:
> When the hash algorithm for the signature is not available the digest size
> is 0 and the signature in the certificate is marked as unsupported.
>
> When validating a self-signed certificate, this needs to be checked,
> because otherwise trying to validate the signature will fail with an
> warning:
>
> Loading compiled-in X.509 certificates
> WARNING: CPU: 0 PID: 1 at crypto/rsa-pkcs1pad.c:537 \
> pkcs1pad_verify+0x46/0x12c
> ...
> Problem loading in-kernel X.509 certificate (-22)
>
> Signed-off-by: Thore Sommer <public@thson.de>
> ---
>  crypto/asymmetric_keys/x509_public_key.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
> index 6fdfc82e23a8..7c71db3ac23d 100644
> --- a/crypto/asymmetric_keys/x509_public_key.c
> +++ b/crypto/asymmetric_keys/x509_public_key.c
> @@ -130,6 +130,11 @@ int x509_check_for_self_signed(struct x509_certificate *cert)
>  			goto out;
>  	}
>  
> +	if (cert->unsupported_sig) {
> +		ret = 0;
> +		goto out;
> +	}
> +
>  	ret = public_key_verify_signature(cert->pub, cert->sig);
>  	if (ret < 0) {
>  		if (ret == -ENOPKG) {
> -- 
> 2.41.0

Should have:

Cc: stable@vger.kernel.org # v4.7+
Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier")

BR, Jarkko

Re: [PATCH] X.509: if signature is unsupported skip validation

Posted by Thore Sommer 2 years, 3 months ago

On 16.08.23 23:54, Jarkko Sakkinen wrote:
> On Tue Aug 15, 2023 at 2:29 PM EEST, Thore Sommer wrote:
>> When the hash algorithm for the signature is not available the digest size
>> is 0 and the signature in the certificate is marked as unsupported.
>>
>> When validating a self-signed certificate, this needs to be checked,
>> because otherwise trying to validate the signature will fail with an
>> warning:
>>
>> Loading compiled-in X.509 certificates
>> WARNING: CPU: 0 PID: 1 at crypto/rsa-pkcs1pad.c:537 \
>> pkcs1pad_verify+0x46/0x12c
>> ...
>> Problem loading in-kernel X.509 certificate (-22)
>>
>> Signed-off-by: Thore Sommer <public@thson.de>
>> ---
>>   crypto/asymmetric_keys/x509_public_key.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
>> index 6fdfc82e23a8..7c71db3ac23d 100644
>> --- a/crypto/asymmetric_keys/x509_public_key.c
>> +++ b/crypto/asymmetric_keys/x509_public_key.c
>> @@ -130,6 +130,11 @@ int x509_check_for_self_signed(struct x509_certificate *cert)
>>   			goto out;
>>   	}
>>   
>> +	if (cert->unsupported_sig) {
>> +		ret = 0;
>> +		goto out;
>> +	}
>> +
>>   	ret = public_key_verify_signature(cert->pub, cert->sig);
>>   	if (ret < 0) {
>>   		if (ret == -ENOPKG) {
>> -- 
>> 2.41.0
> 
> Should have:
> 
> Cc: stable@vger.kernel.org # v4.7+
> Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier")
> 
> BR, Jarkko

Hi Jarkko,

should I resend it with the stable mailing list in CC or will it be 
added when a maintainer includes the change?

Best regards,
Thore

Re: [PATCH] X.509: if signature is unsupported skip validation

Posted by Jarkko Sakkinen 2 years, 3 months ago

On Mon Aug 21, 2023 at 1:30 PM EEST, Thore Sommer wrote:
> On 16.08.23 23:54, Jarkko Sakkinen wrote:
> > On Tue Aug 15, 2023 at 2:29 PM EEST, Thore Sommer wrote:
> >> When the hash algorithm for the signature is not available the digest size
> >> is 0 and the signature in the certificate is marked as unsupported.
> >>
> >> When validating a self-signed certificate, this needs to be checked,
> >> because otherwise trying to validate the signature will fail with an
> >> warning:
> >>
> >> Loading compiled-in X.509 certificates
> >> WARNING: CPU: 0 PID: 1 at crypto/rsa-pkcs1pad.c:537 \
> >> pkcs1pad_verify+0x46/0x12c
> >> ...
> >> Problem loading in-kernel X.509 certificate (-22)
> >>
> >> Signed-off-by: Thore Sommer <public@thson.de>
> >> ---
> >>   crypto/asymmetric_keys/x509_public_key.c | 5 +++++
> >>   1 file changed, 5 insertions(+)
> >>
> >> diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
> >> index 6fdfc82e23a8..7c71db3ac23d 100644
> >> --- a/crypto/asymmetric_keys/x509_public_key.c
> >> +++ b/crypto/asymmetric_keys/x509_public_key.c
> >> @@ -130,6 +130,11 @@ int x509_check_for_self_signed(struct x509_certificate *cert)
> >>   			goto out;
> >>   	}
> >>   
> >> +	if (cert->unsupported_sig) {
> >> +		ret = 0;
> >> +		goto out;
> >> +	}
> >> +
> >>   	ret = public_key_verify_signature(cert->pub, cert->sig);
> >>   	if (ret < 0) {
> >>   		if (ret == -ENOPKG) {
> >> -- 
> >> 2.41.0
> > 
> > Should have:
> > 
> > Cc: stable@vger.kernel.org # v4.7+
> > Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier")
> > 
> > BR, Jarkko
>
> Hi Jarkko,
>
> should I resend it with the stable mailing list in CC or will it be 
> added when a maintainer includes the change?

AFAIK the correct tags, and automation takes care of the rest.

If there is a merge conflict to some stable branch, the bots will call
back to you :-)

BR, Jarkko