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354 lines (300 loc) · 9.64 KB
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# -*- coding: utf-8 -*-
# MinIO Python Library for Amazon S3 Compatible Cloud Storage,
# (C) 2015-2020 MinIO, Inc.
#
# 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.
"""
minio.signer
~~~~~~~~~~~~~~~
This module implements all helpers for AWS Signature version '4' support.
:copyright: (c) 2015 by MinIO, Inc.
:license: Apache 2.0, see LICENSE for more details.
"""
from __future__ import absolute_import, annotations
import hashlib
import hmac
import re
from collections import OrderedDict
from datetime import datetime
from typing import Mapping, cast
from urllib.parse import SplitResult
from . import time
from .credentials import Credentials
from .helpers import DictType, queryencode, sha256_hash
SIGN_V4_ALGORITHM = 'AWS4-HMAC-SHA256'
_MULTI_SPACE_REGEX = re.compile(r"( +)")
def _hmac_hash(
key: bytes,
data: bytes,
hexdigest: bool = False,
) -> bytes | str:
"""Return HMacSHA256 digest of given key and data."""
hasher = hmac.new(key, data, hashlib.sha256)
return hasher.hexdigest() if hexdigest else hasher.digest()
def _get_scope(date: datetime, region: str, service_name: str) -> str:
"""Get scope string."""
return f"{time.to_signer_date(date)}/{region}/{service_name}/aws4_request"
def _get_canonical_headers(
headers: Mapping[str, str | list[str] | tuple[str]],
) -> tuple[str, str]:
"""Get canonical headers."""
ordered_headers = {}
for key, values in headers.items():
key = key.lower()
if key not in (
"authorization",
"user-agent",
):
values = values if isinstance(values, (list, tuple)) else [values]
ordered_headers[key] = ",".join([
_MULTI_SPACE_REGEX.sub(" ", value).strip() for value in values
])
ordered_headers = OrderedDict(sorted(ordered_headers.items()))
signed_headers = ";".join(ordered_headers.keys())
canonical_headers = "\n".join(
[f"{key}:{value}" for key, value in ordered_headers.items()],
)
return canonical_headers, signed_headers
def _get_canonical_query_string(query: str) -> str:
"""Get canonical query string."""
query = query or ""
return "&".join(
[
"=".join(pair) for pair in sorted(
[params.split("=") for params in query.split("&")],
)
],
)
def _get_canonical_request_hash(
method: str,
url: SplitResult,
headers: Mapping[str, str | list[str] | tuple[str]],
content_sha256: str,
) -> tuple[str, str]:
"""Get canonical request hash."""
canonical_headers, signed_headers = _get_canonical_headers(headers)
canonical_query_string = _get_canonical_query_string(url.query)
# CanonicalRequest =
# HTTPRequestMethod + '\n' +
# CanonicalURI + '\n' +
# CanonicalQueryString + '\n' +
# CanonicalHeaders + '\n\n' +
# SignedHeaders + '\n' +
# HexEncode(Hash(RequestPayload))
canonical_request = (
f"{method}\n"
f"{url.path or '/'}\n"
f"{canonical_query_string}\n"
f"{canonical_headers}\n\n"
f"{signed_headers}\n"
f"{content_sha256}"
)
return sha256_hash(canonical_request), signed_headers
def _get_string_to_sign(
date: datetime,
scope: str,
canonical_request_hash: str,
) -> str:
"""Get string-to-sign."""
return (
f"AWS4-HMAC-SHA256\n{time.to_amz_date(date)}\n{scope}\n"
f"{canonical_request_hash}"
)
def _get_signing_key(
secret_key: str,
date: datetime,
region: str,
service_name: str,
) -> bytes:
"""Get signing key."""
date_key = cast(
bytes,
_hmac_hash(
("AWS4" + secret_key).encode(),
time.to_signer_date(date).encode(),
),
)
date_region_key = cast(bytes, _hmac_hash(date_key, region.encode()))
date_region_service_key = cast(
bytes,
_hmac_hash(date_region_key, service_name.encode()),
)
return cast(
bytes,
_hmac_hash(date_region_service_key, b"aws4_request"),
)
def _get_signature(signing_key: bytes, string_to_sign: str) -> str:
"""Get signature."""
return cast(
str,
_hmac_hash(signing_key, string_to_sign.encode(), hexdigest=True),
)
def _get_authorization(
access_key: str,
scope: str,
signed_headers: str,
signature: str,
) -> str:
"""Get authorization."""
return (
f"AWS4-HMAC-SHA256 Credential={access_key}/{scope}, "
f"SignedHeaders={signed_headers}, Signature={signature}"
)
def _sign_v4(
*,
service_name: str,
method: str,
url: SplitResult,
region: str,
headers: DictType,
credentials: Credentials,
content_sha256: str,
date: datetime,
) -> DictType:
"""Do signature V4 of given request for given service name."""
scope = _get_scope(date, region, service_name)
canonical_request_hash, signed_headers = _get_canonical_request_hash(
method, url, headers, content_sha256,
)
string_to_sign = _get_string_to_sign(date, scope, canonical_request_hash)
signing_key = _get_signing_key(
credentials.secret_key, date, region, service_name,
)
signature = _get_signature(signing_key, string_to_sign)
authorization = _get_authorization(
credentials.access_key, scope, signed_headers, signature,
)
headers["Authorization"] = authorization
return headers
def sign_v4_s3(
*,
method: str,
url: SplitResult,
region: str,
headers: DictType,
credentials: Credentials,
content_sha256: str,
date: datetime,
) -> DictType:
"""Do signature V4 of given request for S3 service."""
return _sign_v4(
service_name="s3",
method=method,
url=url,
region=region,
headers=headers,
credentials=credentials,
content_sha256=content_sha256,
date=date,
)
def sign_v4_sts(
*,
method: str,
url: SplitResult,
region: str,
headers: DictType,
credentials: Credentials,
content_sha256: str,
date: datetime,
) -> DictType:
"""Do signature V4 of given request for STS service."""
return _sign_v4(
service_name="sts",
method=method,
url=url,
region=region,
headers=headers,
credentials=credentials,
content_sha256=content_sha256,
date=date,
)
def _get_presign_canonical_request_hash( # pylint: disable=invalid-name
*,
method: str,
url: SplitResult,
access_key: str,
scope: str,
date: datetime,
expires: int,
) -> tuple[str, SplitResult]:
"""Get canonical request hash for presign request."""
x_amz_credential = queryencode(access_key + "/" + scope)
canonical_headers, signed_headers = "host:" + url.netloc, "host"
query = url.query+"&" if url.query else ""
query += (
f"X-Amz-Algorithm=AWS4-HMAC-SHA256"
f"&X-Amz-Credential={x_amz_credential}"
f"&X-Amz-Date={time.to_amz_date(date)}"
f"&X-Amz-Expires={expires}"
f"&X-Amz-SignedHeaders={signed_headers}"
)
parts = list(url)
parts[3] = query
url = SplitResult(*parts)
canonical_query_string = _get_canonical_query_string(query)
# CanonicalRequest =
# HTTPRequestMethod + '\n' +
# CanonicalURI + '\n' +
# CanonicalQueryString + '\n' +
# CanonicalHeaders + '\n\n' +
# SignedHeaders + '\n' +
# HexEncode(Hash(RequestPayload))
canonical_request = (
f"{method}\n"
f"{url.path or '/'}\n"
f"{canonical_query_string}\n"
f"{canonical_headers}\n\n"
f"{signed_headers}\n"
f"UNSIGNED-PAYLOAD"
)
return sha256_hash(canonical_request), url
def presign_v4(
*,
method: str,
url: SplitResult,
region: str,
credentials: Credentials,
date: datetime,
expires: int,
) -> SplitResult:
"""Do signature V4 of given presign request."""
scope = _get_scope(date, region, "s3")
canonical_request_hash, url = _get_presign_canonical_request_hash(
method=method,
url=url,
access_key=credentials.access_key,
scope=scope,
date=date,
expires=expires,
)
string_to_sign = _get_string_to_sign(date, scope, canonical_request_hash)
signing_key = _get_signing_key(credentials.secret_key, date, region, "s3")
signature = _get_signature(signing_key, string_to_sign)
parts = list(url)
parts[3] = url.query + "&X-Amz-Signature=" + queryencode(signature)
url = SplitResult(*parts)
return url
def get_credential_string(access_key: str, date: datetime, region: str) -> str:
"""Get credential string of given access key, date and region."""
return f"{access_key}/{time.to_signer_date(date)}/{region}/s3/aws4_request"
def post_presign_v4(
data: str,
secret_key: str,
date: datetime,
region: str,
) -> str:
"""Do signature V4 of given presign POST form-data."""
return _get_signature(
_get_signing_key(secret_key, date, region, "s3"),
data,
)