Support IMDSv2 HttpTokens

changelog/63067.added

@@ -0,0 +1 @@
+salt-cloud support IMDSv2 tokens when using 'use-instance-role-credentials'

salt/utils/aws.py

@@ -8,15 +8,12 @@ This is a base library used by a number of AWS services.
 :depends: requests
 """
 
-import binascii
 import hashlib
 import hmac
 import logging
 import random
 import re
 import time
-import urllib.parse
-import xml.etree.ElementTree as ET
 from datetime import datetime
 
 import salt.config
@@ -30,6 +27,27 @@ try:
 except ImportError:
     HAS_REQUESTS = False  # pylint: disable=W0612
 
+try:
+    import binascii
+
+    HAS_BINASCII = True  # pylint: disable=W0612
+except ImportError:
+    HAS_BINASCII = False  # pylint: disable=W0612
+
+try:
+    import urllib.parse
+
+    HAS_URLLIB = True  # pylint: disable=W0612
+except ImportError:
+    HAS_URLLIB = False  # pylint: disable=W0612
+
+try:
+    import xml.etree.ElementTree as ET
+
+    HAS_ETREE = True  # pylint: disable=W0612
+except ImportError:
+    HAS_ETREE = False  # pylint: disable=W0612
+
 # pylint: enable=import-error,redefined-builtin,no-name-in-module
 
 log = logging.getLogger(__name__)
@@ -54,6 +72,7 @@ __Token__ = ""
 __Expiration__ = ""
 __Location__ = ""
 __AssumeCache__ = {}
+__IMDS_Token__ = None
 
 
 def sleep_exponential_backoff(attempts):
@@ -71,6 +90,44 @@ def sleep_exponential_backoff(attempts):
     time.sleep(random.uniform(1, 2**attempts))
 
 
+def get_metadata(path, refresh_token_if_needed=True):
+    """
+    Get the instance metadata at the provided path
+    The path argument will be prepended by http://169.254.169.254/latest/
+    If using IMDSv2 with tokens required, the token will be fetched and used for subsequent requests
+    (unless refresh_token_if_needed is False, in which case this will fail if tokens are required
+    and no token was already cached)
+    """
+    global __IMDS_Token__
+
+    headers = {}
+    if __IMDS_Token__ is not None:
+        headers["X-aws-ec2-metadata-token"] = __IMDS_Token__
+
+    # Connections to instance meta-data must fail fast and never be proxied
+    result = requests.get(
+        "http://169.254.169.254/latest/{}".format(path),
+        proxies={"http": ""},
+        headers=headers,
+        timeout=AWS_METADATA_TIMEOUT,
+    )
+
+    if result.status_code == 401 and refresh_token_if_needed:
+        # Probably using IMDSv2 with tokens required, so fetch token and retry
+        token_result = requests.put(
+            "http://169.254.169.254/latest/api/token",
+            headers={"X-aws-ec2-metadata-token-ttl-seconds": "21600"},
+            proxies={"http": ""},
+            timeout=AWS_METADATA_TIMEOUT,
+        )
+        __IMDS_Token__ = token_result.text
+        if token_result.ok:
+            return get_metadata(path, False)
+
+    result.raise_for_status()
+    return result
+
+
 def creds(provider):
     """
     Return the credentials for AWS signing.  This could be just the id and key
@@ -95,27 +152,14 @@ def creds(provider):
                 return __AccessKeyId__, __SecretAccessKey__, __Token__
         # We don't have any cached credentials, or they are expired, get them
 
-        # Connections to instance meta-data must fail fast and never be proxied
         try:
-            result = requests.get(
-                "http://169.254.169.254/latest/meta-data/iam/security-credentials/",
-                proxies={"http": ""},
-                timeout=AWS_METADATA_TIMEOUT,
-            )
-            result.raise_for_status()
+            result = get_metadata("meta-data/iam/security-credentials/")
             role = result.text
         except (requests.exceptions.HTTPError, requests.exceptions.ConnectionError):
             return provider["id"], provider["key"], ""
 
         try:
-            result = requests.get(
-                "http://169.254.169.254/latest/meta-data/iam/security-credentials/{}".format(
-                    role
-                ),
-                proxies={"http": ""},
-                timeout=AWS_METADATA_TIMEOUT,
-            )
-            result.raise_for_status()
+            result = get_metadata("meta-data/iam/security-credentials/{}".format(role))
         except (requests.exceptions.HTTPError, requests.exceptions.ConnectionError):
             return provider["id"], provider["key"], ""
 
@@ -578,12 +622,7 @@ def get_region_from_metadata():
         return __Location__
 
     try:
-        # Connections to instance meta-data must fail fast and never be proxied
-        result = requests.get(
-            "http://169.254.169.254/latest/dynamic/instance-identity/document",
-            proxies={"http": ""},
-            timeout=AWS_METADATA_TIMEOUT,
-        )
+        result = get_metadata("dynamic/instance-identity/document")
     except requests.exceptions.RequestException:
         log.warning("Failed to get AWS region from instance metadata.", exc_info=True)
         # Do not try again

tests/pytests/unit/utils/test_aws.py

@@ -0,0 +1,52 @@
+"""
+    tests.unit.utils.aws_test
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Test the salt aws functions
+"""
+
+import io
+
+import requests
+
+from salt.utils.aws import get_metadata
+from tests.support.mock import MagicMock, patch
+
+
+def test_get_metadata_imdsv1():
+    response = requests.Response()
+    response.status_code = 200
+    response.reason = "OK"
+    response.raw = io.BytesIO(b"""test""")
+    with patch("requests.get", return_value=response):
+        result = get_metadata("/")
+        assert result.text == "test"
+
+
+def test_get_metadata_imdsv2():
+    mock_token = "abc123"
+
+    def handle_get_mock(_, **args):
+        response = requests.Response()
+        if (
+            "X-aws-ec2-metadata-token" in args["headers"]
+            and args["headers"]["X-aws-ec2-metadata-token"] == mock_token
+        ):
+            response.status_code = 200
+            response.reason = "OK"
+            response.raw = io.BytesIO(b"""test""")
+        else:
+            response.status_code = 401
+            response.reason = "Unauthorized"
+        return response
+
+    put_response = requests.Response()
+    put_response.status_code = 200
+    put_response.reason = "OK"
+    put_response.raw = io.BytesIO(mock_token.encode("utf-8"))
+
+    with patch("requests.get", MagicMock(side_effect=handle_get_mock)), patch(
+        "requests.put", return_value=put_response
+    ):
+        result = get_metadata("/")
+        assert result.text == "test"