fix verification of signatures produced with pki11 #142
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The documentation of the `SignatureLayer::new` method was mentioning a parameter that no longer exists. Signed-off-by: Flavio Castelli <fcastelli@suse.com>
The `cosign` tool can produce signatures using a PKCS11 token. These signatures feature a `certificate` annotation inside of their OCI layer. However, when `COSIGN_EXPERIMENTAL` is not enabled, the layer will not feature a Rekor bundle. Prior to this commit, the code assumed signature layers could have a `certificate` annotation only when using the Fulcio integration. Because of that, layers with a `certificate` but without a Rekor bundle were discarded. That was done to ensure the robustness of keyless verification. This commit changes the code that creates `SignatureLayer` objects to not raise errors when an embedded certificate cannot be verified. Be it because it has been forged/invalid/etc or because the Rekor bundle is not found inside of the layer. The resulting `SignatureLayer` will not be discarded, but it will have its `certificate_signature` attribute set to `None`. > **Note:** `SignatureLayer::certificate_signature` was already a `Option` > before of this commit. The verification constraints implementing keyless verification will discard these kind of layers because they do not have a `certificate_signature`. However, the public key based verifier will be able to verify the signature stored inside of the layer. This solves the following scenario: > Given Alice signed a container image using a PKCS11 token but without having cosign's Rekor integration enabled > When verifying the container image signature using the public key associated with the certificate stored on her PKCS11 token > Then the container image will be reported as successfully verified Fixes sigstore#135 Signed-off-by: Flavio Castelli <fcastelli@suse.com>
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Address clippy and rustfmt warnings Signed-off-by: Flavio Castelli <fcastelli@suse.com>
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viccuad
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Oct 13, 2022
| SigstoreError::SigstoreFulcioCertificatesNotProvidedError | ||
| )); | ||
| ); | ||
| assert!(cert.is_none()); |
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I think the test functions should be renamed now, e.g:
get_certificate_signature_from_annotations_fails_when_no_bundle_is_given()
get_certificate_signature_from_annotations_fails_when_no_fulcio_pub_key_is_given()
should be renamed to [...]_returns_none()
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I like this approach. This PR fix #135 by not failing if the certificate in the |
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Fixes ===== * fix verification of signatures produced with PKI11 (sigstore#142) Others ====== * Update rsa dependency to stable version 0.7.0 (sigstore#141) * Bump actions/checkout from 3.0.2 to 3.1.0 (sigstore#140) Contributors ============ * Flavio Castelli (@flavio) * Xynnn (@Xynnn007) Signed-off-by: Flavio Castelli <fcastelli@suse.com>
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The
cosigntool can produce signatures using a PKCS11 token. These signatures feature acertificateannotation inside of their OCI layer.However, when
COSIGN_EXPERIMENTALis not enabled, the layer will not feature a Rekor bundle.Prior to this commit, the code assumed signature layers could have a
certificateannotation only when using the Fulcio integration. Because of that, layers with acertificatebut without a Rekor bundle were discarded. That was done to ensure the robustness of keyless verification.This commit changes the code that creates
SignatureLayerobjects to not raise errors when an embedded certificate cannot be verified. Be it because it has been forged/invalid/etc or because the Rekor bundle is not found inside of the layer.The resulting
SignatureLayerwill not be discarded, but it will have itscertificate_signatureattribute set toNone.The verification constraints implementing keyless verification will discard these kind of layers because they do not have a
certificate_signature.However, the public key based verifier will be able to verify the signature stored inside of the layer.
This solves the following scenario:
Fixes #135