[2.12] Add accept_newhostkey option to git module (#73819)

* Add integration test for accept_newhostkey option

* Add changelog

changelogs/fragments/73819-git-accept_new_host_key.yaml

@@ -0,0 +1,3 @@
+---
+minor_changes:
+  - git - Add ``accept_newhostkey`` option (https://github.com/ansible/ansible/issues/69846).

lib/ansible/modules/git.py

@@ -48,6 +48,15 @@ options:
         type: bool
         default: 'no'
         version_added: "1.5"
+    accept_newhostkey:
+        description:
+            - As of OpenSSH 7.5, "-o StrictHostKeyChecking=accept-new" can be
+              used which is safer and will only accepts host keys which are
+              not present or are the same. if C(yes), ensure that
+              "-o StrictHostKeyChecking=accept-new" is present as an ssh option.
+        type: bool
+        default: 'no'
+        version_added: "2.12"
     ssh_opts:
         description:
             - Creates a wrapper script and exports the path as GIT_SSH
@@ -317,6 +326,7 @@ from distutils.version import LooseVersion
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.six import b, string_types
 from ansible.module_utils._text import to_native, to_text
+from ansible.module_utils.common.process import get_bin_path
 
 
 def relocate_repo(module, result, repo_dir, old_repo_dir, worktree_dir):
@@ -462,6 +472,21 @@ def get_version(module, git_path, dest, ref="HEAD"):
     return sha
 
 
+def ssh_supports_acceptnewhostkey(module):
+    try:
+        ssh_path = get_bin_path('ssh')
+    except ValueError as err:
+        module.fail_json(
+            msg='Remote host is missing ssh command, so you cannot '
+            'use acceptnewhostkey option.', details=to_text(err))
+    supports_acceptnewhostkey = True
+    cmd = [ssh_path, '-o', 'StrictHostKeyChecking=accept-new', '-V']
+    rc, stdout, stderr = module.run_command(cmd)
+    if rc != 0:
+        supports_acceptnewhostkey = False
+    return supports_acceptnewhostkey
+
+
 def get_submodule_versions(git_path, module, dest, version='HEAD'):
     cmd = [git_path, 'submodule', 'foreach', git_path, 'rev-parse', version]
     (rc, out, err) = module.run_command(cmd, cwd=dest)
@@ -1107,6 +1132,7 @@ def main():
             verify_commit=dict(default='no', type='bool'),
             gpg_whitelist=dict(default=[], type='list', elements='str'),
             accept_hostkey=dict(default='no', type='bool'),
+            accept_newhostkey=dict(default='no', type='bool'),
             key_file=dict(default=None, type='path', required=False),
             ssh_opts=dict(default=None, required=False),
             executable=dict(default=None, type='path'),
@@ -1119,7 +1145,7 @@ def main():
             archive_prefix=dict(),
             separate_git_dir=dict(type='path'),
         ),
-        mutually_exclusive=[('separate_git_dir', 'bare')],
+        mutually_exclusive=[('separate_git_dir', 'bare'), ('accept_hostkey', 'accept_newhostkey')],
         required_by={'archive_prefix': ['archive']},
         supports_check_mode=True
     )
@@ -1150,11 +1176,21 @@ def main():
 
     if module.params['accept_hostkey']:
         if ssh_opts is not None:
-            if "-o StrictHostKeyChecking=no" not in ssh_opts:
+            if ("-o StrictHostKeyChecking=no" not in ssh_opts) and ("-o StrictHostKeyChecking=accept-new" not in ssh_opts):
                 ssh_opts += " -o StrictHostKeyChecking=no"
         else:
             ssh_opts = "-o StrictHostKeyChecking=no"
 
+    if module.params['accept_newhostkey']:
+        if not ssh_supports_acceptnewhostkey(module):
+            module.warn("Your ssh client does not support accept_newhostkey option, therefore it cannot be used.")
+        else:
+            if ssh_opts is not None:
+                if ("-o StrictHostKeyChecking=no" not in ssh_opts) and ("-o StrictHostKeyChecking=accept-new" not in ssh_opts):
+                    ssh_opts += " -o StrictHostKeyChecking=accept-new"
+            else:
+                ssh_opts = "-o StrictHostKeyChecking=accept-new"
+
     # evaluate and set the umask before doing anything else
     if umask is not None:
         if not isinstance(umask, string_types):

test/integration/targets/git/tasks/main.yml

@@ -21,6 +21,7 @@
 
 - import_tasks: formats.yml
 - import_tasks: missing_hostkey.yml
+- import_tasks: missing_hostkey_acceptnew.yml
 - import_tasks: no-destination.yml
 - import_tasks: specific-revision.yml
 - import_tasks: submodules.yml

test/integration/targets/git/tasks/missing_hostkey.yml

@@ -46,3 +46,16 @@
     that:
       - git_result is changed
   when: github_ssh_private_key is defined
+
+- name: MISSING-HOSTEKY | Remove github.com hostkey from known_hosts
+  lineinfile:
+    dest: '{{ output_dir }}/known_hosts'
+    regexp: "github.com"
+    state: absent
+  when: github_ssh_private_key is defined
+
+- name: MISSING-HOSTKEY | clear checkout_dir
+  file:
+    state: absent
+    path: '{{ checkout_dir }}'
+  when: github_ssh_private_key is defined

test/integration/targets/git/tasks/missing_hostkey_acceptnew.yml

@@ -0,0 +1,78 @@
+- name: MISSING-HOSTKEY | check accept_newhostkey support
+  shell: ssh -o StrictHostKeyChecking=accept-new -V
+  register: ssh_supports_accept_newhostkey
+  ignore_errors: true
+
+- block:
+    - name: MISSING-HOSTKEY | accept_newhostkey when ssh does not support the option
+      git:
+        repo: '{{ repo_format2 }}'
+        dest: '{{ checkout_dir }}'
+        accept_newhostkey: true
+        ssh_opts: '-o UserKnownHostsFile={{ output_dir }}/known_hosts'
+      register: git_result
+      ignore_errors: true
+
+    - assert:
+        that:
+          - git_result is failed
+          - git_result.warnings is search("does not support")
+
+  when: ssh_supports_accept_newhostkey.rc != 0
+
+- name: MISSING-HOSTKEY | checkout ssh://git@github.com repo without accept_newhostkey (expected fail)
+  git:
+    repo: '{{ repo_format2 }}'
+    dest: '{{ checkout_dir }}'
+    ssh_opts: '-o UserKnownHostsFile={{ output_dir }}/known_hosts'
+  register: git_result
+  ignore_errors: true
+
+- assert:
+    that:
+      - git_result is failed
+
+- block:
+    - name: MISSING-HOSTKEY | checkout git@github.com repo with accept_newhostkey (expected pass)
+      git:
+        repo: '{{ repo_format2 }}'
+        dest: '{{ checkout_dir }}'
+        accept_newhostkey: true
+        key_file: '{{ github_ssh_private_key }}'
+        ssh_opts: '-o UserKnownHostsFile={{ output_dir }}/known_hosts'
+      register: git_result
+
+    - assert:
+        that:
+          - git_result is changed
+
+    - name: MISSING-HOSTKEY | clear checkout_dir
+      file:
+        state: absent
+        path: '{{ checkout_dir }}'
+
+    - name: MISSING-HOSTKEY | checkout ssh://git@github.com repo with accept_newhostkey (expected pass)
+      git:
+        repo: '{{ repo_format3 }}'
+        dest: '{{ checkout_dir }}'
+        version: 'master'
+        accept_newhostkey: false # should already have been accepted
+        key_file: '{{ github_ssh_private_key }}'
+        ssh_opts: '-o UserKnownHostsFile={{ output_dir }}/known_hosts'
+      register: git_result
+
+    - assert:
+        that:
+          - git_result is changed
+
+    - name: MISSING-HOSTEKY | Remove github.com hostkey from known_hosts
+      lineinfile:
+        dest: '{{ output_dir }}/known_hosts'
+        regexp: "github.com"
+        state: absent
+
+    - name: MISSING-HOSTKEY | clear checkout_dir
+      file:
+        state: absent
+        path: '{{ checkout_dir }}'
+  when: github_ssh_private_key is defined and ssh_supports_accept_newhostkey.rc == 0