Adds github client and PAT inspection (#138)

* Adds github client and PAT inspection * CI, Python version fixes Consolidate exceptions Signed-off-by: Caroline Russell <caroline@appthreat.dev> Output exception Signed-off-by: Caroline Russell <caroline@appthreat.dev> Handle GitHubException Signed-off-by: Caroline Russell <caroline@appthreat.dev> Don't fail-fast version_tests2 Signed-off-by: Caroline Russell <caroline@appthreat.dev> Fix type hints, unnecessary test runs Signed-off-by: Caroline Russell <caroline@appthreat.dev> * Addressing PR concerns * Adds 3.12 tests (#137) * Adds 3.12 tests Signed-off-by: Prabhu Subramanian <prabhu@appthreat.com> * Adds 3.12 tests Signed-off-by: Prabhu Subramanian <prabhu@appthreat.com> --------- Signed-off-by: Prabhu Subramanian <prabhu@appthreat.com> * Update to work with GitHub Actions tokens --------- Signed-off-by: Caroline Russell <caroline@appthreat.dev> Signed-off-by: Prabhu Subramanian <prabhu@appthreat.com> Co-authored-by: Tim Messing <141575989+timmyteo@users.noreply.github.com> Co-authored-by: Caroline Russell <caroline@appthreat.dev> Co-authored-by: prabhu <prabhu@appthreat.com>
owasp-dep-scan · Oct 25, 2023 · 54dd761 · 54dd761
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commit 54dd761
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diff --git a/.github/workflows/dockertests.yml b/.github/workflows/dockertests.yml
@@ -7,6 +7,9 @@ on:
       - feature/*
     paths-ignore:
       - '**/README.md'
+      - 'gobintests.yml'
+      - 'pythonapp.yml'
+      - 'python-publish.yml'
   pull_request:
 jobs:
   ubuntu_version_tests:
@@ -58,6 +61,7 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         python-version: ['3.11']
+      fail-fast: false
     steps:
     - uses: actions/checkout@v4
     - name: Set up Python

diff --git a/.github/workflows/gobintests.yml b/.github/workflows/gobintests.yml
@@ -6,13 +6,17 @@ on:
       - master
     paths-ignore:
       - '**/README.md'
+      - 'dockertests.yml'
+      - 'pythonapp.yml'
+      - 'python-publish.yml'
   pull_request:
 jobs:
   build:
     runs-on: ubuntu-latest
     strategy:
       matrix:
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
+      fail-fast: false
     steps:
     - uses: actions/checkout@v4
     - name: Set up Python

diff --git a/.github/workflows/pythonapp.yml b/.github/workflows/pythonapp.yml
@@ -4,6 +4,9 @@ on:
   push:
     paths-ignore:
       - '**/README.md'
+      - 'dockertests.yml'
+      - 'dockertests.yml'
+      - 'python-publish.yml'
   pull_request:
 jobs:
   build:
@@ -12,6 +15,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
+      fail-fast: false
     steps:
     - uses: actions/checkout@v4
     - name: Set up Python

diff --git a/.github/workflows/pythonpublish.yml b/.github/workflows/pythonpublish.yml
@@ -6,6 +6,9 @@ on:
   push:
     paths-ignore:
       - '**/README.md'
+      - 'dockertests.yml'
+      - 'pythonapp.yml'
+      - 'gobintests.yml'
     branches:
       - master
     tags:

diff --git a/README.md b/README.md
@@ -308,9 +308,10 @@ The following environment variables can be used to customise the behaviour.
 
 ## GitHub Security Advisory
 
-To download security advisories from GitHub, a personal access token with the following scope is necessary.
+To download security advisories from GitHub, a personal access token with minimal permissions is necessary.
 
-- read:packages
+- Fine-grained token: Grant no permissions and select the following for repository access: `Public Repositories (read-only)`
+- Token (classic): Grant no permissions
 
 ```bash
 export GITHUB_TOKEN="<PAT token>"

diff --git a/depscan/cli.py b/depscan/cli.py
@@ -20,6 +20,7 @@
 
 import oras.client
 
+from depscan.lib import privado, utils, github
 from depscan.lib.csaf import export_csaf, write_toml
 from depscan.lib import privado, utils
 from depscan.lib.analysis import (
@@ -791,8 +792,20 @@ def main():
             )
 
         sources_list = [OSVSource(), NvdSource()]
-        if os.environ.get("GITHUB_TOKEN"):
-            sources_list.insert(0, GitHubSource())
+        github_token = os.environ.get("GITHUB_TOKEN")
+        if github_token:
+            github_client = github.GitHub(github_token)
+
+            if not github_client.can_authenticate():
+                LOG.error("The GitHub personal access token supplied appears to be invalid or expired. Please see: https://github.com/owasp-dep-scan/dep-scan#github-security-advisory")
+            else:
+                sources_list.insert(0, GitHubSource())
+                scopes = github_client.get_token_scopes()
+                if not scopes is None and len(scopes) > 0:
+                    LOG.warning(
+                        "The GitHub personal access token was granted more permissions than is necessary for depscan to operate, including the scopes of: %s. It is recommended to use a dedicated token with only the minimum scope necesary for depscan to operate. Please see: https://github.com/owasp-dep-scan/dep-scan#github-security-advisory",
+                        ', '.join([scope for scope in scopes])
+                    )
         if run_cacher:
             LOG.debug(
                 "About to download vdb from %s. This might take a while ...",

diff --git a/depscan/lib/github.py b/depscan/lib/github.py
@@ -0,0 +1,62 @@
+from github import Github, Auth
+from depscan.lib import config
+import httpx
+
+
+class GitHub:
+    # The GitHub instance object from the PyGithub library
+    github = None
+    github_token = None
+
+
+    def __init__(self, github_token: str) -> None:
+        self.github = Github(auth=Auth.Token(github_token))
+        self.github_token = github_token
+
+
+    def can_authenticate(self) -> bool:
+        """
+        Calls the GitHub API to determine if the token is valid
+
+        :return: Flag indicating whether authentication was successful or not
+        """
+        headers = {"Authorization": f"token {self.github_token}"}
+
+        response = httpx.get(
+            url='https://api.github.com/',
+            headers=headers,
+            follow_redirects=True,
+            timeout=config.request_timeout_sec
+        )
+
+        if response.status_code == 401:
+            return False
+        else:
+            return True
+
+
+    def get_token_scopes(self) -> list:
+        """
+        Provides the scopes associated to the access token provided in the environment variable
+        Only classic personal access tokens will result in scopes returned from the GitHub API
+
+        :return: List of token scopes
+        """
+        headers = {"Authorization": f"token {self.github_token}"}
+
+        response = httpx.get(
+            url='https://api.github.com/',
+            headers=headers,
+            follow_redirects=True,
+            timeout=config.request_timeout_sec
+        )
+
+        oauth_scopes = response.headers.get('x-oauth-scopes')
+
+        if not oauth_scopes is None:
+            if oauth_scopes == '':
+                return None
+            else:
+                return oauth_scopes.split(', ')
+
+        return None
diff --git a/pyproject.toml b/pyproject.toml
@@ -12,6 +12,7 @@ dependencies = [
     "PyYAML",
     "rich",
     "quart",
+    "PyGithub",
     "toml",
 ]
 
@@ -44,7 +45,8 @@ scan = "depscan.cli:main"
 dev = ["black",
 "flake8",
 "pytest",
-"pytest-cov"
+"pytest-cov",
+"httpretty"
 ]
 
 [build-system]

diff --git a/test/test_github.py b/test/test_github.py
@@ -0,0 +1,122 @@
+from depscan.lib import github
+import httpretty
+
+
+url = 'https://api.github.com/'
+
+
+def test_can_authenticate_success():
+    httpretty.enable()
+    httpretty.reset()
+
+    headers = {
+        'content-type': 'application/json',
+        'X-OAuth-Scopes': 'admin:org, admin:repo_hook, repo, user',
+        'X-Accepted-OAuth-Scopes': 'repo'
+    }
+
+    httpretty.register_uri(
+        method=httpretty.GET,
+        uri=url,
+        adding_headers=headers
+    )
+
+    github_client = github.GitHub('test-token')
+    result = github_client.can_authenticate()
+
+    httpretty.disable()
+
+    assert result == True
+
+
+def test_can_authenticate_unauthentiated():
+    httpretty.enable()
+    httpretty.reset()
+
+    headers = {
+        'content-type': 'application/json'
+    }
+
+    httpretty.register_uri(
+        method=httpretty.GET,
+        uri=url,
+        body='{"message":"Bad credentials"}',
+        adding_headers=headers,
+        status=401
+    )
+
+    github_client = github.GitHub('test-token')
+    result = github_client.can_authenticate()
+
+    httpretty.disable()
+
+    assert result == False
+
+
+def test_get_token_scopes_success():
+    httpretty.enable()
+    httpretty.reset()
+
+    headers = {
+        'content-type': 'application/json',
+        'X-OAuth-Scopes': 'admin:org, admin:repo_hook, repo, user',
+        'X-Accepted-OAuth-Scopes': 'repo'
+    }
+
+    httpretty.register_uri(
+        method=httpretty.GET,
+        uri=url,
+        adding_headers=headers
+    )
+
+    github_client = github.GitHub('test-token')
+    result = github_client.get_token_scopes()
+
+    httpretty.disable()
+
+    assert len(result) == 4 and result.index('admin:org') >= 0 and result.index('admin:repo_hook') >= 0 and result.index('repo') >= 0 and result.index('user') >= 0
+
+
+def test_get_token_scopes_none():
+    httpretty.enable()
+    httpretty.reset()
+
+    headers = {
+        'content-type': 'application/json',
+    }
+
+    httpretty.register_uri(
+        method=httpretty.GET,
+        uri=url,
+        adding_headers=headers
+    )
+
+    github_client = github.GitHub('test-token')
+    result = github_client.get_token_scopes()
+
+    httpretty.disable()
+
+    assert result is None
+
+
+def test_get_token_scopes_empty():
+    httpretty.enable()
+    httpretty.reset()
+
+    headers = {
+        'content-type': 'application/json',
+        'x-oauth-scopes': ''
+    }
+
+    httpretty.register_uri(
+        method=httpretty.GET,
+        uri=url,
+        adding_headers=headers
+    )
+
+    github_client = github.GitHub('test-token')
+    result = github_client.get_token_scopes()
+
+    httpretty.disable()
+
+    assert result is None