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Add public key validation #1598

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Mar 13, 2022
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7 changes: 7 additions & 0 deletions pkg/apis/cosigned/v1alpha1/clusterimagepolicy_validation.go
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ import (
"context"
"strings"

"github.com/sigstore/cosign/pkg/apis/utils"
"knative.dev/pkg/apis"
)

Expand Down Expand Up @@ -93,6 +94,12 @@ func (key *KeyRef) Validate(ctx context.Context) *apis.FieldError {
if key.KMS != "" || key.SecretRef != nil {
errs = errs.Also(apis.ErrMultipleOneOf("data", "kms", "secretref"))
}
validPubkey := utils.IsValidKey([]byte(key.Data))
if !validPubkey {
errs = errs.Also(
apis.ErrInvalidValue(key.Data, "data"),
)
}
} else if key.KMS != "" && key.SecretRef != nil {
errs = errs.Also(apis.ErrMultipleOneOf("data", "kms", "secretref"))
}
Expand Down
44 changes: 43 additions & 1 deletion pkg/apis/cosigned/v1alpha1/clusterimagepolicy_validation_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -115,14 +115,56 @@ func TestKeyValidation(t *testing.T) {
Authorities: []Authority{
{
Key: &KeyRef{
Data: "---some key data----",
Data: "-----BEGIN PUBLIC KEY-----\nMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEaEOVJCFtduYr3xqTxeRWSW32CY/s\nTBNZj4oIUPl8JvhVPJ1TKDPlNcuT4YphSt6t3yOmMvkdQbCj8broX6vijw==\n-----END PUBLIC KEY-----",
KMS: "kms://key/path",
},
},
},
},
},
},
{
name: "Should fail when key has mixed valid and invalid data: %v",
expectErr: true,
errorString: "invalid value: -----BEGIN PUBLIC KEY-----\nMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEaEOVJCFtduYr3xqTxeRWSW32CY/s\nTBNZj4oIUPl8JvhVPJ1TKDPlNcuT4YphSt6t3yOmMvkdQbCj8broX6vijw==\n-----END PUBLIC KEY-----\n---somedata---",
policy: ClusterImagePolicy{
Spec: ClusterImagePolicySpec{
Images: []ImagePattern{
{
Glob: "myglob",
},
},
Authorities: []Authority{
{
Key: &KeyRef{
Data: "-----BEGIN PUBLIC KEY-----\nMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEaEOVJCFtduYr3xqTxeRWSW32CY/s\nTBNZj4oIUPl8JvhVPJ1TKDPlNcuT4YphSt6t3yOmMvkdQbCj8broX6vijw==\n-----END PUBLIC KEY-----\n---somedata---",
},
},
},
},
},
},
{
name: "Should fail when key has malformed pubkey data: %v",
expectErr: true,
errorString: "invalid value: ---some key data----",
policy: ClusterImagePolicy{
Spec: ClusterImagePolicySpec{
Images: []ImagePattern{
{
Glob: "myglob",
},
},
Authorities: []Authority{
{
Key: &KeyRef{
Data: "---some key data----",
},
},
},
},
},
},
{
name: "Should fail when key is empty: %v",
expectErr: true,
Expand Down
52 changes: 52 additions & 0 deletions pkg/apis/utils/key_validations.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,52 @@
// 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.

package utils

import (
"crypto/x509"
"encoding/pem"
)

func IsValidKey(b []byte) bool {
valid := true
pems, validPEM := parsePEMKey(b)
if !validPEM {
return false
}

for _, p := range pems {
_, err := x509.ParsePKIXPublicKey(p.Bytes)
if err != nil {
return false
}
}

return valid
}

func parsePEMKey(b []byte) ([]*pem.Block, bool) {
pemKey, rest := pem.Decode(b)
valid := true
if pemKey == nil {
return nil, false
}
pemBlocks := []*pem.Block{pemKey}

if len(rest) > 0 {
list, check := parsePEMKey(rest)
return append(pemBlocks, list...), check
}
return pemBlocks, valid
}
6 changes: 5 additions & 1 deletion test/testdata/cosigned/invalid/both-regex-and-pattern.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -22,4 +22,8 @@ spec:
regex: image.*
authorities:
- key:
data: "---somedata---"
data: |
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEZxAfzrQG1EbWyCI8LiSB7YgSFXoI
FNGTyQGKHFc6/H8TQumT9VLS78pUwtv3w7EfKoyFZoP32KrO7nzUy2q6Cw==
-----END PUBLIC KEY-----
24 changes: 24 additions & 0 deletions test/testdata/cosigned/invalid/invalid-pubkey.yaml
Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
# 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.
---
apiVersion: cosigned.sigstore.dev/v1alpha1
kind: ClusterImagePolicy
metadata:
name: image-policy
spec:
images:
- glob: image*
authorities:
- key:
data: "---somedata---"
Original file line number Diff line number Diff line change
Expand Up @@ -21,5 +21,9 @@ spec:
- glob: image*
authorities:
- key:
data: "---somedata---"
data: |
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEZxAfzrQG1EbWyCI8LiSB7YgSFXoI
FNGTyQGKHFc6/H8TQumT9VLS78pUwtv3w7EfKoyFZoP32KrO7nzUy2q6Cw==
-----END PUBLIC KEY-----
kms: "kms://url"
Original file line number Diff line number Diff line change
Expand Up @@ -24,4 +24,4 @@ spec:
identities:
- issuer: "issue-details"
key:
data: "---somekey---"
kms: "kms://url"
8 changes: 5 additions & 3 deletions test/testdata/cosigned/valid/valid-policy.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -21,8 +21,6 @@ spec:
- glob: images.*
- glob: image*
authorities:
- key:
data: "---another-public-key---"
- keyless:
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I removed another-public-key and fixed the code validating the key.

ca-key:
secretRef:
Expand All @@ -36,7 +34,11 @@ spec:
identities:
- issuer: "issue-details1"
- key:
data: "---some-key---"
data: |
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEaEOVJCFtduYr3xqTxeRWSW32CY/s
TBNZj4oIUPl8JvhVPJ1TKDPlNcuT4YphSt6t3yOmMvkdQbCj8broX6vijw==
-----END PUBLIC KEY-----
- key:
kms: "kms://key/path"
- key:
Expand Down