mirror of
https://github.com/edgelesssys/constellation.git
synced 2024-10-01 01:36:09 -04:00
62 lines
1.9 KiB
Go
62 lines
1.9 KiB
Go
/*
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Copyright (c) Edgeless Systems GmbH
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SPDX-License-Identifier: AGPL-3.0-only
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*/
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package sigstore
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import (
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"bytes"
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"crypto"
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"encoding/base64"
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"fmt"
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"github.com/edgelesssys/constellation/v2/internal/api/versionsapi"
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"github.com/edgelesssys/constellation/v2/internal/constants"
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"github.com/sigstore/sigstore/pkg/cryptoutils"
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sigsig "github.com/sigstore/sigstore/pkg/signature"
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)
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// CosignVerifier checks if the signature of content can be verified
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// using a cosign public key.
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type CosignVerifier struct{}
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// VerifySignature checks if the signature of content can be verified
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// using publicKey.
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// signature is expected to be base64 encoded.
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// publicKey is expected to be PEM encoded.
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func (CosignVerifier) VerifySignature(content, signature, publicKey []byte) error {
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sigRaw := base64.NewDecoder(base64.StdEncoding, bytes.NewReader(signature))
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pubKeyRaw, err := cryptoutils.UnmarshalPEMToPublicKey(publicKey)
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if err != nil {
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return fmt.Errorf("unable to parse public key: %w", err)
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}
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if err := cryptoutils.ValidatePubKey(pubKeyRaw); err != nil {
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return fmt.Errorf("unable to validate public key: %w", err)
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}
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verifier, err := sigsig.LoadVerifier(pubKeyRaw, crypto.SHA256)
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if err != nil {
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return fmt.Errorf("unable to load verifier: %w", err)
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}
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if err := verifier.VerifySignature(sigRaw, bytes.NewReader(content)); err != nil {
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return fmt.Errorf("unable to verify signature: %w", err)
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}
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return nil
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}
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// CosignPublicKeyForVersion returns the public key for the given version.
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func CosignPublicKeyForVersion(ver versionsapi.Version) ([]byte, error) {
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if err := ver.Validate(); err != nil {
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return nil, fmt.Errorf("selecting public key: invalid version %s: %w", ver.ShortPath(), err)
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}
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if ver.Ref == versionsapi.ReleaseRef && ver.Stream == "stable" {
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return []byte(constants.CosignPublicKeyReleases), nil
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}
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return []byte(constants.CosignPublicKeyDev), nil
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}
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