Made PKey.from_path cert-aware & tilde-friendly

This was previously only done in SSHClient.

It's not relevant for from_type_string which is aimed at ssh-agents,
which tend to do their own cert loading where necessary

4 files changed, 87 insertions, 1 deletions

diff --git a/tests/_support/rsa-lonely.key b/tests/_support/rsa-lonely.key
new file mode 100644
index 00000000..f50e9c53
--- /dev/null
+++ b/tests/_support/rsa-lonely.key
@@ -0,0 +1,15 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
diff --git a/tests/_support/rsa-missing.key-cert.pub b/tests/_support/rsa-missing.key-cert.pub
new file mode 100644
index 00000000..7487ab66
--- /dev/null
+++ b/tests/_support/rsa-missing.key-cert.pub
@@ -0,0 +1 @@
+ssh-rsa-cert-v01@openssh.com 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 test_rsa.key.pub
diff --git a/tests/auth.py b/tests/auth.py
index a12aa5fe..5d732218 100644
--- a/tests/auth.py
+++ b/tests/auth.py
@@ -9,6 +9,7 @@ from pytest import raises
 from paramiko import (
     RSAKey,
     DSSKey,
+    PKey,
     BadAuthenticationType,
     AuthenticationException,
     SSHException,
@@ -165,6 +166,27 @@ class AuthOnlyHandler_:
                 assert tc._agreed_pubkey_algorithm == "ssh-rsa"
 
         @requires_sha1_signing
+        def key_type_algo_selection_is_cert_suffix_aware(self):
+            # This key has a cert next to it, which should trigger cert-aware
+            # loading within key classes.
+            privkey = PKey.from_path(_support("rsa.key"))
+            server_init = dict(_disable_sha2_pubkey, server_sig_algs=False)
+            with self._server(
+                pubkeys=[privkey],
+                connect=dict(pkey=privkey),
+                server_init=server_init,
+                catch_error=True,
+            ) as (tc, ts, err):
+                assert not err
+                # Auth did work
+                assert tc.is_authenticated()
+                # Selected expected cert type
+                assert (
+                    tc._agreed_pubkey_algorithm
+                    == "ssh-rsa-cert-v01@openssh.com"
+                )
+
+        @requires_sha1_signing
         def uses_first_preferred_algo_if_key_type_not_in_list(self):
             # This is functionally the same as legacy AuthHandler, just
             # arriving at the same place in a different manner.
diff --git a/tests/pkey.py b/tests/pkey.py
index 98193165..25202a06 100644
--- a/tests/pkey.py
+++ b/tests/pkey.py
@@ -1,7 +1,14 @@
 from pytest import raises
 
 from cryptography.hazmat.primitives.asymmetric.ed448 import Ed448PrivateKey
-from paramiko import PKey, Ed25519Key, RSAKey, UnknownKeyType, Message
+from paramiko import (
+    PKey,
+    Ed25519Key,
+    RSAKey,
+    UnknownKeyType,
+    Message,
+    PublicBlob,
+)
 
 from ._util import _support
 
@@ -37,6 +44,47 @@ class PKey_:
             with raises(ValueError):
                 PKey.from_path(__file__)
 
+        class automatically_loads_certificates:
+            def existing_cert_loaded_when_given_key_path(self):
+                key = PKey.from_path(_support("rsa.key"))
+                # Public blob exists despite no .load_certificate call
+                assert key.public_blob is not None
+                assert (
+                    key.public_blob.key_type == "ssh-rsa-cert-v01@openssh.com"
+                )
+                # And it's definitely the one we expected
+                assert key.public_blob == PublicBlob.from_file(
+                    _support("rsa.key-cert.pub")
+                )
+
+            def can_be_given_cert_path_instead(self):
+                key = PKey.from_path(_support("rsa.key-cert.pub"))
+                # It's still a key, not a PublicBlob
+                assert isinstance(key, RSAKey)
+                # Public blob exists despite no .load_certificate call
+                assert key.public_blob is not None
+                assert (
+                    key.public_blob.key_type == "ssh-rsa-cert-v01@openssh.com"
+                )
+                # And it's definitely the one we expected
+                assert key.public_blob == PublicBlob.from_file(
+                    _support("rsa.key-cert.pub")
+                )
+
+            def no_cert_load_if_no_cert(self):
+                # This key exists (it's a copy of the regular one) but has no
+                # matching -cert.pub
+                key = PKey.from_path(_support("rsa-lonely.key"))
+                assert key.public_blob is None
+
+            def excepts_usefully_if_no_key_only_cert(self):
+                # TODO: is that truly an error condition? the cert is ~the
+                # pubkey and we still require the privkey for signing, yea?
+                # This cert exists (it's a copy of the regular one) but there's
+                # no rsa-missing.key to load.
+                with raises(FileNotFoundError) as info:
+                    PKey.from_path(_support("rsa-missing.key-cert.pub"))
+                assert info.value.filename.endswith("rsa-missing.key")
 
     class load_certificate:
         def rsa_public_cert_blobs(self):