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Add verify-blob-attestation command and tests #2337
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Original file line number | Diff line number | Diff line change |
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@@ -279,3 +279,39 @@ The blob may be specified as a path to a file or - for stdin.`, | |
o.AddFlags(cmd) | ||
return cmd | ||
} | ||
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func VerifyBlobAttestation() *cobra.Command { | ||
o := &options.VerifyBlobAttestationOptions{} | ||
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cmd := &cobra.Command{ | ||
Use: "verify-blob-attestation", | ||
Short: "Verify an attestation on the supplied blob", | ||
Long: `Verify an attestation on the supplied blob input using the specified key reference. | ||
You may specify either a key or a kms reference to verify against. | ||
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The signature may be specified as a path to a file or a base64 encoded string. | ||
The blob may be specified as a path to a file.`, | ||
Example: ` cosign verify-blob-attestastion (--key <key path>|<key url>|<kms uri>) --signature <sig> [path to BLOB] | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. nit verify-blob-attestation |
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# Verify a simple blob attestation with a DSSE style signature | ||
cosign verify-blob-attestastion --key cosign.pub (--signature <sig path>|<sig url>)[path to BLOB] | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. ditto. |
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`, | ||
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Args: cobra.ExactArgs(1), | ||
RunE: func(cmd *cobra.Command, args []string) error { | ||
v := verify.VerifyBlobAttestationCommand{ | ||
KeyRef: o.Key, | ||
PredicateType: o.PredicateOptions.Type, | ||
SignaturePath: o.SignaturePath, | ||
} | ||
if len(args) != 1 { | ||
return fmt.Errorf("no path to blob passed in, run `cosign verify-blob-attestation -h` for more help") | ||
} | ||
return v.Exec(cmd.Context(), args[0]) | ||
}, | ||
} | ||
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o.AddFlags(cmd) | ||
return cmd | ||
} |
Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,167 @@ | ||
// | ||
// Copyright 2022 the Sigstore Authors. | ||
// | ||
// Licensed under the Apache License, Version 2.0 (the "License"); | ||
// you may not use this file except in compliance with the License. | ||
// You may obtain a copy of the License at | ||
// | ||
// http://www.apache.org/licenses/LICENSE-2.0 | ||
// | ||
// Unless required by applicable law or agreed to in writing, software | ||
// distributed under the License is distributed on an "AS IS" BASIS, | ||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
// See the License for the specific language governing permissions and | ||
// limitations under the License. | ||
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package verify | ||
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import ( | ||
"bytes" | ||
"context" | ||
"crypto" | ||
"encoding/base64" | ||
"encoding/hex" | ||
"encoding/json" | ||
"fmt" | ||
"os" | ||
"path/filepath" | ||
"strings" | ||
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"github.com/in-toto/in-toto-golang/in_toto" | ||
ssldsse "github.com/secure-systems-lab/go-securesystemslib/dsse" | ||
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"github.com/sigstore/cosign/cmd/cosign/cli/options" | ||
"github.com/sigstore/cosign/pkg/cosign" | ||
"github.com/sigstore/cosign/pkg/cosign/pkcs11key" | ||
sigs "github.com/sigstore/cosign/pkg/signature" | ||
"github.com/sigstore/cosign/pkg/types" | ||
"github.com/sigstore/sigstore/pkg/signature" | ||
"github.com/sigstore/sigstore/pkg/signature/dsse" | ||
) | ||
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// VerifyBlobAttestationCommand verifies an attestation on a supplied blob | ||
// nolint | ||
type VerifyBlobAttestationCommand struct { | ||
CheckClaims bool | ||
KeyRef string | ||
PredicateType string | ||
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SignaturePath string // Path to the signature | ||
} | ||
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// Exec runs the verification command | ||
func (c *VerifyBlobAttestationCommand) Exec(ctx context.Context, artifactPath string) error { | ||
if c.SignaturePath == "" { | ||
return fmt.Errorf("please specify path to the base64 encoded DSSE envelope signature via --signature") | ||
} | ||
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// TODO: Add support for security keys and keyless signing | ||
if !options.OneOf(c.KeyRef) { | ||
return &options.PubKeyParseError{} | ||
} | ||
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var err error | ||
co := &cosign.CheckOpts{} | ||
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if c.CheckClaims { | ||
co.ClaimVerifier = cosign.IntotoSubjectClaimVerifier | ||
} | ||
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keyRef := c.KeyRef | ||
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// TODO: keyless signing | ||
co.SigVerifier, err = sigs.PublicKeyFromKeyRef(ctx, keyRef) | ||
if err != nil { | ||
return fmt.Errorf("loading public key: %w", err) | ||
} | ||
pkcs11Key, ok := co.SigVerifier.(*pkcs11key.Key) | ||
if ok { | ||
defer pkcs11Key.Close() | ||
} | ||
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// Read the signature and decode it (it should be base64-encoded) | ||
encodedSig, err := os.ReadFile(filepath.Clean(c.SignaturePath)) | ||
if err != nil { | ||
return fmt.Errorf("reading %s: %w", c.SignaturePath, err) | ||
} | ||
decodedSig, err := base64.StdEncoding.DecodeString(string(encodedSig)) | ||
if err != nil { | ||
return fmt.Errorf("decoding signature: %w", err) | ||
} | ||
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// Verify the signature on the attestation against the provided public key | ||
env := ssldsse.Envelope{} | ||
if err := json.Unmarshal(decodedSig, &env); err != nil { | ||
return fmt.Errorf("marshaling envelope: %w", err) | ||
} | ||
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if env.PayloadType != types.IntotoPayloadType { | ||
return cosign.NewVerificationError("invalid payloadType %s on envelope. Expected %s", env.PayloadType, types.IntotoPayloadType) | ||
} | ||
dssev, err := ssldsse.NewEnvelopeVerifier(&dsse.VerifierAdapter{SignatureVerifier: co.SigVerifier}) | ||
if err != nil { | ||
return fmt.Errorf("new envelope verifier: %w", err) | ||
} | ||
if _, err := dssev.Verify(&env); err != nil { | ||
return fmt.Errorf("dsse verify: %w", err) | ||
} | ||
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// Verify the attestation is for the provided blob and the predicate type | ||
if err := verifyBlobAttestation(env, artifactPath, c.PredicateType); err != nil { | ||
return err | ||
} | ||
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fmt.Fprintln(os.Stderr, "Verified OK") | ||
return nil | ||
} | ||
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func verifyBlobAttestation(env ssldsse.Envelope, blobPath, predicateType string) error { | ||
artifact, err := os.ReadFile(blobPath) | ||
if err != nil { | ||
return fmt.Errorf("reading %s: %w", blobPath, err) | ||
} | ||
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// Get the actual digest of the blob | ||
digest, _, err := signature.ComputeDigestForSigning(bytes.NewReader(artifact), crypto.SHA256, []crypto.Hash{crypto.SHA256, crypto.SHA384}) | ||
if err != nil { | ||
return err | ||
} | ||
actualDigest := strings.ToLower(hex.EncodeToString(digest)) | ||
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// Get the expected digest from the attestation | ||
decodedPredicate, err := base64.StdEncoding.DecodeString(env.Payload) | ||
if err != nil { | ||
return fmt.Errorf("decoding dsse payload: %w", err) | ||
} | ||
var statement in_toto.Statement | ||
if err := json.Unmarshal(decodedPredicate, &statement); err != nil { | ||
return fmt.Errorf("decoding predicate: %w", err) | ||
} | ||
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// Compare the actual and expected | ||
if statement.Subject == nil { | ||
return fmt.Errorf("no subject in intoto statement") | ||
} | ||
if len(statement.Subject) != 1 { | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. should this definitely be a requirement? if the attestation signed over say, a jar file and a pom file, the attestation should verify against the jar file, right? There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. it's sad that There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Ah I added this in because |
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return fmt.Errorf("expected one subject in intoto statement") | ||
} | ||
subject := statement.Subject[0] | ||
sha256Digest, ok := subject.Digest["sha256"] | ||
if !ok { | ||
return fmt.Errorf("no sha256 digest available") | ||
} | ||
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if sha256Digest != actualDigest { | ||
return fmt.Errorf("expected digest %s but %s has a digest of %s", sha256Digest, blobPath, actualDigest) | ||
} | ||
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// Check the predicate | ||
parsedPredicateType, err := options.ParsePredicateType(predicateType) | ||
if err != nil { | ||
return fmt.Errorf("parsing predicate type %s: %w", predicateType, err) | ||
} | ||
if statement.PredicateType != parsedPredicateType { | ||
return fmt.Errorf("expected predicate type %s but is %s: specify an expected predicate type with the --type flag", parsedPredicateType, statement.PredicateType) | ||
} | ||
return nil | ||
} |
Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,102 @@ | ||
// Copyright 2022 the Sigstore Authors. | ||
// | ||
// Licensed under the Apache License, Version 2.0 (the "License"); | ||
// you may not use this file except in compliance with the License. | ||
// You may obtain a copy of the License at | ||
// | ||
// http://www.apache.org/licenses/LICENSE-2.0 | ||
// | ||
// Unless required by applicable law or agreed to in writing, software | ||
// distributed under the License is distributed on an "AS IS" BASIS, | ||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
// See the License for the specific language governing permissions and | ||
// limitations under the License. | ||
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package verify | ||
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import ( | ||
"encoding/base64" | ||
"encoding/json" | ||
"os" | ||
"path/filepath" | ||
"testing" | ||
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ssldsse "github.com/secure-systems-lab/go-securesystemslib/dsse" | ||
) | ||
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const ( | ||
blobContents = "some-payload" | ||
anotherBlobContents = "another-blob" | ||
blobSLSAProvenanceSignature = "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" | ||
dssePredicateEmptySubject = "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" | ||
dssePredicateMissingSha256 = "ewogICJwYXlsb2FkVHlwZSI6ICJhcHBsaWNhdGlvbi92bmQuaW4tdG90bytqc29uIiwKICAicGF5bG9hZCI6ICJld29nSUNKZmRIbHdaU0k2SUNKb2RIUndjem92TDJsdUxYUnZkRzh1YVc4dlUzUmhkR1Z0Wlc1MEwzWXdMakVpTEFvZ0lDSndjbVZrYVdOaGRHVlVlWEJsSWpvZ0ltaDBkSEJ6T2k4dmMyeHpZUzVrWlhZdmNISnZkbVZ1WVc1alpTOTJNQzR5SWl3S0lDQWljM1ZpYW1WamRDSTZJRnNLSUNBZ0lIc0tJQ0FnSUNBZ0ltNWhiV1VpT2lBaVlteHZZaUlzQ2lBZ0lDQWdJQ0prYVdkbGMzUWlPaUI3Q2lBZ0lDQWdJQ0FnSW01dmRITm9ZVEkxTmlJNklDSTJOVGczT0RGalpEUmxaRGxpWTJFMk1HUmhZMlF3T1dZM1ltSTVNVFJpWWpVeE5UQXlaVGhpTldRMk1UbG1OVGRtTXpsaE1XUTJOVEkxT1Raall6STBJZ29nSUNBZ0lDQjlDaUFnSUNCOUNpQWdYU3dLSUNBaWNISmxaR2xqWVhSbElqb2dld29nSUNBZ0ltSjFhV3hrWlhJaU9pQjdDaUFnSUNBZ0lDSnBaQ0k2SUNJeUlnb2dJQ0FnZlN3S0lDQWdJQ0ppZFdsc1pGUjVjR1VpT2lBaWVDSXNDaUFnSUNBaWFXNTJiMk5oZEdsdmJpSTZJSHNLSUNBZ0lDQWdJbU52Ym1acFoxTnZkWEpqWlNJNklIdDlDaUFnSUNCOUNpQWdmUXA5Q2c9PSIsCiAgInNpZ25hdHVyZXMiOiBbCiAgICB7CiAgICAgICJrZXlpZCI6ICIiLAogICAgICAic2lnIjogIk1HWUNNUURYdmFVUDBmaVh1clRyZk02a1A2NE9wREIzSnNKUTNsUUdlYTlSZkE5UEJjcmZZMk5zR3ErUnQzN2cyWmppSko4Q01RQ01jenNXL3A4YmJ6Rk5KRGp4SGU4U1F1NFNrOEFreG1MR0sxUTZHaVRrMDNvaEdTd2xmRlE1cytNbFFMWkZlekE9IgogICAgfQogIF0KfQo=" | ||
) | ||
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func TestVerifyBlobAttestation(t *testing.T) { | ||
tmpdir := t.TempDir() | ||
blobPath := filepath.Join(tmpdir, "blob") | ||
if err := os.WriteFile(blobPath, []byte(blobContents), 0755); err != nil { | ||
t.Fatal(err) | ||
} | ||
anotherBlobPath := filepath.Join(tmpdir, "another-blob") | ||
if err := os.WriteFile(anotherBlobPath, []byte(anotherBlobContents), 0755); err != nil { | ||
t.Fatal(err) | ||
} | ||
defer os.RemoveAll(tmpdir) | ||
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tests := []struct { | ||
description string | ||
blobPath string | ||
signature string | ||
predicateType string | ||
shouldErr bool | ||
}{ | ||
{ | ||
description: "verify a slsaprovenance predicate", | ||
predicateType: "slsaprovenance", | ||
blobPath: blobPath, | ||
signature: blobSLSAProvenanceSignature, | ||
}, { | ||
description: "fail with incorrect predicate", | ||
signature: blobSLSAProvenanceSignature, | ||
blobPath: blobPath, | ||
predicateType: "custom", | ||
shouldErr: true, | ||
}, { | ||
description: "fail with incorrect blob", | ||
signature: blobSLSAProvenanceSignature, | ||
blobPath: anotherBlobPath, | ||
shouldErr: true, | ||
}, { | ||
description: "dsse envelope predicate has no subject", | ||
signature: dssePredicateEmptySubject, | ||
blobPath: blobPath, | ||
shouldErr: true, | ||
}, { | ||
description: "dsse envelope predicate missing sha256 digest", | ||
signature: dssePredicateMissingSha256, | ||
blobPath: blobPath, | ||
shouldErr: true, | ||
}, | ||
} | ||
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for _, test := range tests { | ||
t.Run(test.description, func(t *testing.T) { | ||
decodedSig, err := base64.StdEncoding.DecodeString(test.signature) | ||
if err != nil { | ||
t.Fatal(err) | ||
} | ||
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// Verify the signature on the attestation against the provided public key | ||
env := ssldsse.Envelope{} | ||
if err := json.Unmarshal(decodedSig, &env); err != nil { | ||
t.Fatal(err) | ||
} | ||
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err = verifyBlobAttestation(env, test.blobPath, test.predicateType) | ||
if (err != nil) != test.shouldErr { | ||
t.Fatalf("verifyBlobAttestation()= %s, expected shouldErr=%t ", err, test.shouldErr) | ||
} | ||
}) | ||
} | ||
} |
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nit, this seems like cut&paste?
VerifyBlobAttestationOptions is ...
verify-blob-attestation
command.