derivepassphrase.git

@@ -11,8 +11,6 @@ import os

 import shutil

 import socket

 import subprocess

-import sys

-import textwrap

 from typing import TYPE_CHECKING, TypeVar

 import hypothesis

@@ -24,7 +22,6 @@ from derivepassphrase import _types, ssh_agent

 if TYPE_CHECKING:

     from collections.abc import Iterator

-    from typing import Literal

 startup_ssh_auth_sock = os.environ.get('SSH_AUTH_SOCK', None)

@@ -68,12 +65,12 @@ def skip_if_no_af_unix_support() -> None:  # pragma: no cover

 def _spawn_pageant(  # pragma: no cover

     executable: str | None, env: dict[str, str]

-) -> tuple[subprocess.Popen[str], bool] | None:

+) -> subprocess.Popen[str] | None:

     """Spawn an isolated Pageant, if possible.

     We attempt to detect whether Pageant is usable, i.e. whether Pageant

     has output buffering problems when announcing its authentication

-    socket.

+    socket.  This is the case for Pageant 0.81 and earlier.

     Args:

         executable:

@@ -83,36 +80,29 @@ def _spawn_pageant(  # pragma: no cover

             include an SSH_AUTH_SOCK variable.

     Returns:

-        (tuple[subprocess.Popen, bool] | None):

-        A 2-tuple `(proc, debug_output)`, where `proc` is the spawned

-        Pageant subprocess, and `debug_output` indicates whether Pageant

-        will continue to emit debug output (that needs to be actively

-        read) or not.

+        The spawned Pageant subprocess.  If the executable is `None`, or

+        if we detect that Pageant cannot be sensibly controlled as

+        a subprocess, then return `None` directly.

         It is the caller's responsibility to clean up the spawned

         subprocess.

-        If the executable is `None`, or if we detect that Pageant is too

-        old to properly flush its output, which prevents readers from

-        learning the SSH_AUTH_SOCK setting needed to connect to Pageant

-        in the first place, then return `None` directly.

-

     """

     if executable is None:  # pragma: no cover

         return None

-    pageant_features = {'flush': False, 'foreground': False}

-

     # Apparently, Pageant 0.81 and lower running in debug mode does

     # not actively flush its output.  As a result, the first two

     # lines, which set the SSH_AUTH_SOCK and the SSH_AGENT_PID, only

     # print once the output buffer is flushed, whenever that is.

     #

-    # This has been reported to the PuTTY developers.

-    #

-    # For testing purposes, I currently build a version of Pageant with

-    # output flushing fixed and with a `--foreground` option.  This is

-    # detected here.

+    # This has been reported to the PuTTY developers.  It is fixed in

+    # version 0.82, though the PuTTY developers consider this to be an

+    # abuse of debug mode.  A new foreground mode (`--foreground`), also

+    # introduced in 0.82, provides the desired behavior: no forking, and

+    # immediately parsable instructions for SSH_AUTH_SOCK and

+    # SSH_AGENT_PID.

+

     help_output = subprocess.run(

         ['pageant', '--help'],

         executable=executable,

@@ -127,44 +117,14 @@ def _spawn_pageant(  # pragma: no cover

         if len(help_lines) >= 2

         else ''

     )

-    v0_81 = packaging.version.Version('0.81')

-    if pageant_version_string not in {'', 'Unidentified build'}:

-        # TODO(the-13th-letter): Once a fixed Pageant is released,

-        # remove the check for build information in the version string.

-        # https://github.com/the-13th-letter/derivepassphrase/issues/14

-        pageant_version_string_numeric, local_segment_list = (

-            pageant_version_string.split('+', 1)

-            if '+' in pageant_version_string

-            else (pageant_version_string, '')

-        )

-        local_segments = frozenset(local_segment_list.split('+'))

-        pageant_version = packaging.version.Version(

-            pageant_version_string_numeric

-        )

-        for key in pageant_features:

-            pageant_features[key] = pageant_version > v0_81 or (

-                pageant_version == v0_81 and key in local_segments

-            )

+    v0_82 = packaging.version.Version('0.82')

+    pageant_version = packaging.version.Version(pageant_version_string)

-    if not pageant_features['flush']:  # pragma: no cover

+    if pageant_version < v0_82:  # pragma: no cover

         return None

-    # Because Pageant's debug mode prints debugging information on

-    # standard output, and because we yield control to a different

-    # thread of execution, we cannot read-and-discard Pageant's output

-    # here.  Instead, spawn a consumer process and connect it to

-    # Pageant's standard output; see _spawn_data_sink.

-    #

-    # This will hopefully not be necessary with newer Pageants:

-    # a feature request for a `--foreground` option that just avoids the

-    # forking behavior has been submitted.

-

     return subprocess.Popen(

-        [

-            'pageant',

-            '--foreground' if pageant_features['foreground'] else '--debug',

-            '-s',

-        ],

+        ['pageant', '--foreground', '-s'],

         executable=executable,

         stdin=subprocess.DEVNULL,

         stdout=subprocess.PIPE,

@@ -172,18 +132,14 @@ def _spawn_pageant(  # pragma: no cover

         env=env,

         text=True,

         bufsize=1,

-    ), not pageant_features['foreground']

+    )

 def _spawn_openssh_agent(  # pragma: no cover

     executable: str | None, env: dict[str, str]

-) -> tuple[subprocess.Popen[str], Literal[False]] | None:

+) -> subprocess.Popen[str] | None:

     """Spawn an isolated OpenSSH agent, if possible.

-    We attempt to detect whether Pageant is usable, i.e. whether Pageant

-    has output buffering problems when announcing its authentication

-    socket.

-

     Args:

         executable:

             The path to the OpenSSH agent executable.

@@ -192,17 +148,12 @@ def _spawn_openssh_agent(  # pragma: no cover

             not include an SSH_AUTH_SOCK variable.

     Returns:

-        (tuple[subprocess.Popen, Literal[False]] | None):

-        A 2-tuple `(proc, debug_output)`, where `proc` is the spawned

-        OpenSSH agent subprocess, and `debug_output` indicates whether

-        the OpenSSH agent will continue to emit debug output that needs

-        to be actively read (which it doesn't, so this is always false).

+        The spawned OpenSSH agent subprocess.  If the executable is

+        `None`, then return `None` directly.

         It is the caller's responsibility to clean up the spawned

         subprocess.

-        If the executable is `None`, then return `None` directly.

-

     """

     if executable is None:

         return None

@@ -215,7 +166,7 @@ def _spawn_openssh_agent(  # pragma: no cover

         env=env,

         text=True,

         bufsize=1,

-    ), False

+    )

 def _spawn_system_agent(  # pragma: no cover

@@ -245,11 +196,10 @@ def running_ssh_agent(  # pragma: no cover

     can it guarantee a particular set of loaded keys.

     Yields:

-        :

-            A 2-tuple `(ssh_auth_sock, agent_type)`, where

-            `ssh_auth_sock` is the value of the `SSH_AUTH_SOCK`

-            environment variable, to be used to connect to the running

-            agent, and `agent_type` is the agent type.

+        A 2-tuple `(ssh_auth_sock, agent_type)`, where `ssh_auth_sock`

+        is the value of the `SSH_AUTH_SOCK` environment variable, to be

+        used to connect to the running agent, and `agent_type` is the

+        agent type.

     Raises:

         pytest.skip.Exception:

@@ -305,14 +255,9 @@ def running_ssh_agent(  # pragma: no cover

                     os.environ.get('SSH_AUTH_SOCK', None)

                     == startup_ssh_auth_sock

                 ), f'SSH_AUTH_SOCK mismatch when checking for spawnable {exec_name}'  # noqa: E501

-                spawn_data = spawn_func(  # type: ignore[operator]

-                    executable=shutil.which(exec_name), env={}

-                )

-                if spawn_data is None:

+                proc = spawn_func(executable=shutil.which(exec_name), env={})

+                if proc is None:

                     continue

-                proc: subprocess.Popen[str]

-                emits_debug_output: bool

-                proc, emits_debug_output = spawn_data

                 with exit_stack:

                     exit_stack.enter_context(terminate_on_exit(proc))

                     assert (

@@ -333,15 +278,6 @@ def running_ssh_agent(  # pragma: no cover

                         and '_pid' not in pid_line.lower()

                     ):  # pragma: no cover

                         pytest.skip(f'Cannot parse agent output: {pid_line!r}')

-                    proc2 = _spawn_data_sink(

-                        emits_debug_output=emits_debug_output, proc=proc

-                    )

-                    if proc2 is not None:  # pragma: no cover

-                        exit_stack.enter_context(terminate_on_exit(proc2))

-                    assert (

-                        os.environ.get('SSH_AUTH_SOCK', None)

-                        == startup_ssh_auth_sock

-                    ), f'SSH_AUTH_SOCK mismatch after spawning {exec_name} helper'  # noqa: E501

                     monkeypatch2 = exit_stack.enter_context(

                         pytest.MonkeyPatch.context()

                     )

@@ -355,43 +291,8 @@ def running_ssh_agent(  # pragma: no cover

         pytest.skip('No SSH agent running or spawnable')

-def _spawn_data_sink(  # pragma: no cover

-    emits_debug_output: bool, *, proc: subprocess.Popen[str]

-) -> subprocess.Popen[str] | None:

-    """Spawn a data sink to read and discard standard input.

-

-    Necessary for certain SSH agents that emit copious debugging output.

-

-    On UNIX, we can use `cat`, redirected to `/dev/null`.  Otherwise,

-    the most robust thing to do is to spawn Python and repeatedly call

-    `.read()` on `sys.stdin.buffer`.

-

-    """

-    if not emits_debug_output:

-        return None

-    if proc.stdout is None:

-        return None

-    sink_script = textwrap.dedent("""

-    import sys

-    while sys.stdin.buffer.read(4096):

-        pass

-    """)

-    return subprocess.Popen(

-        (

-            ['cat']

-            if os.name == 'posix'

-            else [sys.executable or 'python3', '-c', sink_script]

-        ),

-        executable=sys.executable or None,

-        stdin=proc.stdout.fileno(),

-        stdout=subprocess.DEVNULL,

-        shell=False,

-        text=True,

-    )

-

-

 @pytest.fixture(params=_spawn_handlers, ids=operator.itemgetter(0))

-def spawn_ssh_agent(  # noqa: C901

+def spawn_ssh_agent(

     request: pytest.FixtureRequest,

     skip_if_no_af_unix_support: None,

 ) -> Iterator[tests.SpawnedSSHAgentInfo]:

@@ -402,11 +303,10 @@ def spawn_ssh_agent(  # noqa: C901

     PuTTY's Pageant, and the "(system)" fallback agent.

     Yields:

-        (tests.SpawnedSSHAgentInfo):

-            A [named tuple][collections.namedtuple] containing

-            information about the spawned agent, e.g. the software

-            product, a client connected to the agent, and whether the

-            agent is isolated from other clients.

+        A [named tuple][collections.namedtuple] containing information

+        about the spawned agent, e.g. the software product, a client

+        connected to the agent, and whether the agent is isolated from

+        other clients.

     Raises:

         pytest.skip.Exception:

@@ -471,15 +371,14 @@ def spawn_ssh_agent(  # noqa: C901

             assert (

                 os.environ.get('SSH_AUTH_SOCK', None) == startup_ssh_auth_sock

             ), f'SSH_AUTH_SOCK mismatch when checking for spawnable {exec_name}'  # noqa: E501

-            spawn_data = spawn_func(

+            proc = spawn_func(

                 executable=shutil.which(exec_name), env=agent_env

             )

             assert (

                 os.environ.get('SSH_AUTH_SOCK', None) == startup_ssh_auth_sock

             ), f'SSH_AUTH_SOCK mismatch after spawning {exec_name}'

-            if spawn_data is None:  # pragma: no cover

+            if proc is None:  # pragma: no cover

                 pytest.skip(f'Cannot spawn usable {exec_name}')

-            proc, emits_debug_output = spawn_data

             with exit_stack:

                 exit_stack.enter_context(terminate_on_exit(proc))

                 assert proc.stdout is not None

@@ -502,15 +401,6 @@ def spawn_ssh_agent(  # noqa: C901

                     os.environ.get('SSH_AUTH_SOCK', None)

                     == startup_ssh_auth_sock

                 ), f'SSH_AUTH_SOCK mismatch before spawning {exec_name} helper'

-                proc2 = _spawn_data_sink(

-                    emits_debug_output=emits_debug_output, proc=proc

-                )

-                if proc2 is not None:  # pragma: no cover

-                    exit_stack.enter_context(terminate_on_exit(proc2))

-                assert (

-                    os.environ.get('SSH_AUTH_SOCK', None)

-                    == startup_ssh_auth_sock

-                ), f'SSH_AUTH_SOCK mismatch after spawning {exec_name} helper'

                 monkeypatch2 = exit_stack.enter_context(

                     pytest.MonkeyPatch.context()

                 )

@@ -546,7 +436,6 @@ def ssh_agent_client_with_test_keys_loaded(  # noqa: C901

     automatically assume any particular key is present in the agent.

     Yields:

-        (ssh_agent.SSHAgentClient):

         A [named tuple][collections.namedtuple] containing

         information about the spawned agent, e.g. the software

         product, a client connected to the agent, and whether the

@@ -610,7 +499,7 @@ def ssh_agent_client_with_test_keys_loaded(  # noqa: C901

                     # reasons:

                     #

                     # - Pageant refuses to accept a key it already holds

-                    #   in memory.  Verify this by listing key

+                    #   in memory.  Verify this by listing keys.

                     # - Pageant does not support key constraints (see

                     #   references below).

                     #