mirror of
https://github.com/edgelesssys/constellation.git
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39 lines
1.1 KiB
Go
39 lines
1.1 KiB
Go
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/sigstore/sigstore/pkg/cryptoutils"
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sigsig "github.com/sigstore/sigstore/pkg/signature"
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)
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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 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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