Add Sigstore sign/verify to CLI (#310)

* Update to support Sigstore sign via CLI Signed-off-by: Ivan Font <[email protected]> * Update to support Sigstore verify via CLI Signed-off-by: Ivan Font <[email protected]> * Update docs for Sigstore sign/verify CLI Signed-off-by: Ivan Font <[email protected]> * Update doc to reflect latest CLI changes Signed-off-by: Ivan Font <[email protected]> * Fix sign.py lint errors Signed-off-by: Ivan Font <[email protected]> * Fix verify.py lint errors Signed-off-by: Ivan Font <[email protected]> * Remvoe --method option from doc for required arg Signed-off-by: Ivan Font <[email protected]> * Fix Python type errors Signed-off-by: Ivan Font <[email protected]> --------- Signed-off-by: Ivan Font <[email protected]>
sigstore · Oct 11, 2024 · 1ebab2f · 1ebab2f
1 parent 9e133c4
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diff --git a/README.model_signing.md b/README.model_signing.md
@@ -29,6 +29,7 @@ are supported:
 
 * Bring your own key pair
 * Bring your own PKI
+- Keyless signing using Sigstore with Fulcio root
 * Skip signing (only hash and create a bundle)
 
 The signing part creates a [sigstore bundle](https://github.com/sigstore/protobuf-specs/blob/main/protos/sigstore_bundle.proto)
@@ -68,13 +69,13 @@ $ source .venv/bin/activate
 ## Sign
 
 ```bash
-(.venv) $ python3 sign.py --model_path ${MODEL_PATH} --sig_out ${OUTPUT_PATH} --method {private-key, pki} {additional parameters depending on method}
+(.venv) $ python3 sign.py --model_path ${MODEL_PATH} --sig_out ${SIG_PATH} {private-key, pki, sigstore} {additional parameters depending on method}
 ```
 
 ## Verify
 
 ```bash
-(.venv) $ python3 verify.py --model_path ${MODEL_PATH} --method {private-key, pki} {additional parameters depending on method}
+(.venv) $ python3 verify.py --model_path ${MODEL_PATH} --sig_path ${SIG_PATH} {private-key, pki, sigstore} {additional parameters depending on method}
 ```
 
 ### Examples
@@ -83,14 +84,15 @@ $ source .venv/bin/activate
 
 ```bash
 $ MODEL_PATH='/path/to/your/model'
+$ SIG_PATH='./model.sig'
 $ openssl ecparam -name secp256k1 -genkey -noout -out ec-secp256k1-priv-key.pem
 $ openssl ec -in ec-secp256k1-priv-key.pem -pubout > ec-secp256k1-pub-key.pem
 $ source .venv/bin/activate
 # SIGN
-(.venv) $ python3 sign_model.py --model_path ${MODEL_PATH} --method private-key --private-key ec-secp256k1-priv-key.pem
+(.venv) $ python3 sign.py --model_path ${MODEL_PATH} --sig_out ${SIG_PATH} private-key --private-key ec-secp256k1-priv-key.pem
 ...
 #VERIFY
-(.venv) $ python3 verify_model.py --model_path ${MODEL_PATH} --method private-key --public-key ec-secp256k1-pub-key.pem
+(.venv) $ python3 verify.py --model_path ${MODEL_PATH} --sig_path ${SIG_PATH} private-key --public-key ec-secp256k1-pub-key.pem
 ...
 ```
 
@@ -104,27 +106,42 @@ In order to sign a model with your own PKI you need to create the following info
 
 ```bash
 $ MODEL_PATH='/path/to/your/model'
+$ SIG_PATH='./model.sig'
 $ CERT_CHAIN='/path/to/cert_chain'
 $ SIGNING_CERT='/path/to/signing_certificate'
 $ PRIVATE_KEY='/path/to/private_key'
 # SIGN
-(.venv) $ python3 sign_model.py --model_path ${MODEL_PATH} \
-    --method pki \
+(.venv) $ python3 sign.py --model_path ${MODEL_PATH} \
+    --sig_path ${SIG_PATH} \
+    pki \
     --private-key ${PRIVATE_KEY} \
     --signing_cert ${SIGNING_CERT} \
     [--cert_chain ${CERT_CHAIN}]
 ...
 #VERIFY
 $ ROOT_CERTS='/path/to/root/certs'
-(.venv) $ python3 verify_model.py --model_path ${MODEL_PATH} \
-     --method pki \
-     --root_certs ${ROOT_CERTS}
+(.venv) $ python3 verify.py --model_path ${MODEL_PATH} \
+    --sig_path ${SIG_PATH} \
+    pki \
+    --root_certs ${ROOT_CERTS}
 ...
 ```
 
-## Sigstore ID providers
+#### Keyless signing using Sigstore
 
-For developers signing models, there are three identity providers that can
+```bash
+$ MODEL_PATH='/path/to/your/model'
+# SIGN
+(.venv) $ python3 sign.py --model_path ${MODEL_PATH} sigstore
+...
+#VERIFY
+(.venv) $ python3 verify.py --model_path ${MODEL_PATH} --sig_path ./model.sig sigstore --identity [email protected] --identity-provider https://accounts.example.com
+...
+```
+
+### Sigstore ID providers
+
+For developers signing models with Sigstore, there are three identity providers that can
 be used at the moment:
 
 * Google's provider is `https://accounts.google.com`.
@@ -151,11 +168,13 @@ stored in TFHub, run the following commands:
 
 ```bash
 model_path=bertseq2seq
+sig_path=model.sig
 wget "https://tfhub.dev/google/bertseq2seq/bert24_en_de/1?tf-hub-format=compressed" -O "${model_path}".tgz
 mkdir -p "${model_path}"
 cd "${model_path}" && tar xvzf ../"${model_path}".tgz && rm ../"${model_path}".tgz && cd -
-python3 main.py sign --path "${model_path}"
-python3 main.py verify --path "${model_path}" \
+python3 sign.py --model_path "${model_path}" sigstore
+python3 verify.py --model_path "${model_path}" --sig_path ${sig_path} \
+    sigstore \
     --identity-provider https://accounts.google.com \
     --identity [email protected]
 ```
@@ -173,9 +192,11 @@ After this, we can sign and verify a Bert base model:
 ```bash
 model_name=bert-base-uncased
 model_path="${model_name}"
+sig_path=model.sig
 git clone --depth=1 "https://huggingface.co/${model_name}" && rm -rf "${model_name}"/.git
-python3 main.py sign --path "${model_path}"
-python3 main.py verify --path "${model_path}" \
+python3 sign.py --model_path "${model_path}"
+python3 verify.py --model_path "${model_path}" --sig_path ${sig_path} \
+    sigstore \
     --identity-provider https://accounts.google.com \
     --identity [email protected]
 ```
@@ -185,9 +206,11 @@ Similarly, we can sign and verify a Falcon model:
 ```bash
 model_name=tiiuae/falcon-7b
 model_path=$(echo "${model_name}" | cut -d/ -f2)
+sig_path=model.sig
 git clone --depth=1 "https://huggingface.co/${model_name}" && rm -rf "${model_name}"/.git
-python3 main.py sign --path "${model_path}"
-python3 main.py verify --path "${model_path}" \
+python3 sign.py --model_path "${model_path}"
+python3 verify.py --model_path "${model_path}" --sig_path ${sig_path} \
+    sigstore \
     --identity-provider https://accounts.google.com \
     --identity [email protected]
 ```
@@ -197,11 +220,13 @@ We can also support models from  the PyTorch Hub:
 ```bash
 model_name=hustvl/YOLOP
 model_path=$(echo "${model_name}" | cut -d/ -f2)
+sig_path=model.sig
 wget "https://github.com/${model_name}/archive/main.zip" -O "${model_path}".zip
 mkdir -p "${model_path}"
 cd "${model_path}" && unzip ../"${model_path}".zip && rm ../"${model_path}".zip && shopt -s dotglob && mv YOLOP-main/* . && shopt -u dotglob && rmdir YOLOP-main/ && cd -
-python3 main.py sign --path "${model_path}"
-python3 main.py verify --path "${model_path}" \
+python3 sign.py --model_path "${model_path}"
+python3 verify.py --model_path "${model_path}" --sig_path ${sig_path} \
+    sigstore \
     --identity-provider https://accounts.google.com \
     --identity [email protected]
 ```
@@ -211,9 +236,11 @@ We also support ONNX models, for example Roberta:
 ```bash
 model_name=roberta-base-11
 model_path="${model_name}.onnx"
+sig_path=model.sig
 wget "https://github.com/onnx/models/raw/main/text/machine_comprehension/roberta/model/${model_name}.onnx"
-python3 main.py sign --path "${model_path}"
-python3 main.py verify --path "${model_path}" \
+python3 sign.py --model_path "${model_path}"
+python3 verify.py --model_path "${model_path}" --sig_path ${sig_path} \
+    sigstore \
     --identity-provider https://accounts.google.com \
     --identity [email protected]
 ```

diff --git a/src/sign.py b/src/sign.py
@@ -25,9 +25,10 @@
 from model_signing.signature import fake
 from model_signing.signature import key
 from model_signing.signature import pki
-from model_signing.signature import signing
 from model_signing.signing import in_toto
 from model_signing.signing import in_toto_signature
+from model_signing.signing import signing
+from model_signing.signing import sigstore
 
 
 log = logging.getLogger(__name__)
@@ -54,7 +55,7 @@ def _arguments() -> argparse.Namespace:
     method_cmd = parser.add_subparsers(
         required=True,
         dest="method",
-        help="method to sign the model: [pki, private-key, skip]",
+        help="method to sign the model: [pki, private-key, sigstore, skip]",
     )
     # PKI
     pki = method_cmd.add_parser("pki")
@@ -91,6 +92,17 @@ def _arguments() -> argparse.Namespace:
         type=pathlib.Path,
         dest="key_path",
     )
+    # sigstore
+    sigstore = method_cmd.add_parser("sigstore")
+    sigstore.add_argument(
+        "--use_ambient_credentials",
+        help="use ambient credentials (also known as Workload Identity,"
+        + "default is true)",
+        required=False,
+        type=bool,
+        default=True,
+        dest="use_ambient_credentials",
+    )
     # skip
     method_cmd.add_parser("skip")
 
@@ -100,17 +112,27 @@ def _arguments() -> argparse.Namespace:
 def _get_payload_signer(args: argparse.Namespace) -> signing.Signer:
     if args.method == "private-key":
         _check_private_key_options(args)
-        return key.ECKeySigner.from_path(private_key_path=args.key_path)
+        payload_signer = key.ECKeySigner.from_path(
+            private_key_path=args.key_path
+        )
+        return in_toto_signature.IntotoSigner(payload_signer)
     elif args.method == "pki":
         _check_pki_options(args)
-        return pki.PKISigner.from_path(
+        payload_signer = pki.PKISigner.from_path(
             args.key_path, args.signing_cert_path, args.cert_chain_path
         )
+        return in_toto_signature.IntotoSigner(payload_signer)
+    elif args.method == "sigstore":
+        return sigstore.SigstoreDSSESigner(
+            use_ambient_credentials=args.use_ambient_credentials
+        )
     elif args.method == "skip":
-        return fake.FakeSigner()
+        return in_toto_signature.IntotoSigner(fake.FakeSigner())
     else:
         log.error(f"unsupported signing method {args.method}")
-        log.error('supported methods: ["pki", "private-key", "skip"]')
+        log.error(
+            'supported methods: ["pki", "private-key", "sigstore", "skip"]'
+        )
         exit(-1)
 
 
@@ -151,10 +173,9 @@ def hasher_factory(file_path: pathlib.Path) -> file.FileHasher:
         file_hasher_factory=hasher_factory
     )
 
-    intoto_signer = in_toto_signature.IntotoSigner(payload_signer)
     sig = model.sign(
         model_path=args.model_path,
-        signer=intoto_signer,
+        signer=payload_signer,
         payload_generator=in_toto.DigestsIntotoPayload.from_manifest,
         serializer=serializer,
         ignore_paths=[args.sig_out],

diff --git a/src/verify.py b/src/verify.py
@@ -27,6 +27,8 @@
 from model_signing.signature import pki
 from model_signing.signature import verifying
 from model_signing.signing import in_toto_signature
+from model_signing.signing import signing
+from model_signing.signing import sigstore
 
 
 log = logging.getLogger(__name__)
@@ -51,7 +53,7 @@ def _arguments() -> argparse.Namespace:
     method_cmd = parser.add_subparsers(
         required=True,
         dest="method",
-        help="method to verify the model: [pki, private-key, skip]",
+        help="method to verify the model: [pki, private-key, sigstore, skip]",
     )
     # pki subcommand
     pki = method_cmd.add_parser("pki")
@@ -73,12 +75,52 @@ def _arguments() -> argparse.Namespace:
         type=pathlib.Path,
         dest="key",
     )
-
+    # sigstore subcommand
+    sigstore = method_cmd.add_parser("sigstore")
+    sigstore.add_argument(
+        "--identity",
+        help="the expected identity of the signer e.g. [email protected]",
+        required=True,
+        type=str,
+        dest="identity",
+    )
+    sigstore.add_argument(
+        "--identity-provider",
+        help="the identity provider expected e.g. https://accounts.example.com",
+        required=True,
+        type=str,
+        dest="identity_provider",
+    )
+    # skip subcommand
     method_cmd.add_parser("skip")
 
     return parser.parse_args()
 
 
+def _get_verifier(args: argparse.Namespace) -> signing.Verifier:
+    verifier: verifying.Verifier
+    if args.method == "private-key":
+        _check_private_key_flags(args)
+        verifier = key.ECKeyVerifier.from_path(args.key)
+        return in_toto_signature.IntotoVerifier(verifier)
+    elif args.method == "pki":
+        _check_pki_flags(args)
+        verifier = pki.PKIVerifier.from_paths(args.root_certs)
+        return in_toto_signature.IntotoVerifier(verifier)
+    elif args.method == "sigstore":
+        return sigstore.SigstoreDSSEVerifier(
+            identity=args.identity, oidc_issuer=args.identity_provider
+        )
+    elif args.method == "skip":
+        return in_toto_signature.IntotoVerifier(fake.FakeVerifier())
+    else:
+        log.error(f"unsupported verification method {args.method}")
+        log.error(
+            'supported methods: ["pki", "private-key", "sigstore", "skip"]'
+        )
+        exit(-1)
+
+
 def _check_private_key_flags(args: argparse.Namespace):
     if args.key == "":
         log.error("--public_key must be defined")
@@ -90,28 +132,22 @@ def _check_pki_flags(args: argparse.Namespace):
         log.warning("no root of trust is set using system default")
 
 
+def _get_signature(args: argparse.Namespace) -> signing.Signature:
+    if args.method == "sigstore":
+        return sigstore.SigstoreSignature.read(args.sig_path)
+    else:
+        return in_toto_signature.IntotoSignature.read(args.sig_path)
+
+
 def main():
     logging.basicConfig(level=logging.INFO)
     args = _arguments()
 
-    verifier: verifying.Verifier
     log.info(f"Creating verifier for {args.method}")
-    if args.method == "private-key":
-        _check_private_key_flags(args)
-        verifier = key.ECKeyVerifier.from_path(args.key)
-    elif args.method == "pki":
-        _check_pki_flags(args)
-        verifier = pki.PKIVerifier.from_paths(args.root_certs)
-    elif args.method == "skip":
-        verifier = fake.FakeVerifier()
-    else:
-        log.error(f"unsupported verification method {args.method}")
-        log.error('supported methods: ["pki", "private-key", "skip"]')
-        exit(-1)
-
+    verifier = _get_verifier(args)
     log.info(f"Verifying model signature from {args.sig_path}")
 
-    sig = in_toto_signature.IntotoSignature.read(args.sig_path)
+    sig = _get_signature(args)
 
     def hasher_factory(file_path: pathlib.Path) -> file.FileHasher:
         return file.SimpleFileHasher(
@@ -122,12 +158,10 @@ def hasher_factory(file_path: pathlib.Path) -> file.FileHasher:
         file_hasher_factory=hasher_factory
     )
 
-    intoto_verifier = in_toto_signature.IntotoVerifier(verifier)
-
     try:
         model.verify(
             sig=sig,
-            verifier=intoto_verifier,
+            verifier=verifier,
             model_path=args.model_path,
             serializer=serializer,
             ignore_paths=[args.sig_path],