Merge b2e621cafc into ea117b203b

Because the `HostKeyTest` class was mutating its static/global
`HOST_KEY_TYPES` dict, this class could not actually be used more than once
in a single thread!

Rather than mutate this dict after parsing each key type
(`HOST_KEY_TYPES[host_key_type]['parsed'] = True`), the `perform_test`
method should simple add the parsed key types to a local `set()`.

README.md

@@ -217,6 +217,7 @@ For convenience, a web front-end on top of the command-line tool is available at
  - Added built-in policies for Ubuntu 24.04 LTS server and client, and OpenSSH 9.8.
  - Added IPv6 support for DHEat and connection rate tests.
  - Fixed crash when running with `-P` and `-T` options simultaneously.
+ - Fixed host key tests from only reporting a key type at most once despite multiple hosts supporting it; credit [Daniel Lenski](https://github.com/dlenskiSB).
 
 ### v3.2.0 (2024-04-22)
  - Added implementation of the DHEat denial-of-service attack (see `--dheat` option; [CVE-2002-20001](https://nvd.nist.gov/vuln/detail/CVE-2002-20001)).

src/ssh_audit/gextest.py

@@ -110,7 +110,7 @@ class GEXTest:
                 # before continuing to issue reconnects.
                 modulus_size_returned, reconnect_failed = GEXTest._send_init(out, s, kex_group, kex, gex_alg, bits_min, bits_pref, bits_max)
                 if reconnect_failed:
-                    out.fail('Reconnect failed.')
+                    out.error('Reconnect failed.')
                     return exitcodes.FAILURE
 
                 if modulus_size_returned > 0:

src/ssh_audit/hostkeytest.py

@@ -40,7 +40,7 @@ class HostKeyTest:
     # Tracks the RSA host key types.  As of this writing, testing one in this family yields valid results for the rest.
     RSA_FAMILY = ['ssh-rsa', 'rsa-sha2-256', 'rsa-sha2-512']
 
-    # Dict holding the host key types we should extract & parse.  'cert' is True to denote that a host key type handles certificates (thus requires additional parsing).  'variable_key_len' is True for host key types that can have variable sizes (True only for RSA types, as the rest are of fixed-size).  After the host key type is fully parsed, the key 'parsed' is added with a value of True.
+    # Dict holding the host key types we should extract & parse.  'cert' is True to denote that a host key type handles certificates (thus requires additional parsing).  'variable_key_len' is True for host key types that can have variable sizes (True only for RSA types, as the rest are of fixed-size).
     HOST_KEY_TYPES = {
         'ssh-rsa':      {'cert': False, 'variable_key_len': True},
         'rsa-sha2-256': {'cert': False, 'variable_key_len': True},
@@ -93,6 +93,7 @@ class HostKeyTest:
     def perform_test(out: 'OutputBuffer', s: 'SSH_Socket', server_kex: 'SSH2_Kex', kex_str: str, kex_group: 'KexDH', host_key_types: Dict[str, Dict[str, bool]]) -> None:
         hostkey_modulus_size = 0
         ca_modulus_size = 0
+        parsed_host_key_types = set()
 
         # If the connection still exists, close it so we can test
         # using a clean slate (otherwise it may exist in a non-testable
@@ -106,7 +107,7 @@ class HostKeyTest:
             key_warn_comments = []
 
             # Skip those already handled (i.e.: those in the RSA family, as testing one tests them all).
-            if 'parsed' in host_key_types[host_key_type] and host_key_types[host_key_type]['parsed']:
+            if host_key_type in parsed_host_key_types:
                 continue
 
             # If this host key type is supported by the server, we test it.
@@ -216,7 +217,7 @@ class HostKeyTest:
                 # If this host key type is in the RSA family, then mark them all as parsed (since results in one are valid for them all).
                 if host_key_type in HostKeyTest.RSA_FAMILY:
                     for rsa_type in HostKeyTest.RSA_FAMILY:
-                        host_key_types[rsa_type]['parsed'] = True
+                        parsed_host_key_types.add(rsa_type)
 
                         # If the current key is a member of the RSA family, then populate all RSA family members with the same
                         # failure and/or warning comments.
@@ -228,7 +229,7 @@ class HostKeyTest:
                         db['key'][rsa_type][2].extend(key_warn_comments)
 
                 else:
-                    host_key_types[host_key_type]['parsed'] = True
+                    parsed_host_key_types.add(host_key_type)
                     db = SSH2_KexDB.get_db()
                     while len(db['key'][host_key_type]) < 3:
                         db['key'][host_key_type].append([])

src/ssh_audit/outputbuffer.py

@@ -54,6 +54,14 @@ class OutputBuffer:
         self.__is_color_supported = ('colorama' in sys.modules) or (os.name == 'posix')
         self.line_ended = True
 
+    def error(self, msg, line_ended=True):
+        """
+        Writes an error message to stderr.
+        """
+        end = '' if line_ended else '\n'
+        sys.stderr.write(f'{msg}{end}')
+        sys.stderr.flush()
+        
     def _print(self, level: str, s: str = '', line_ended: bool = True) -> None:
         '''Saves output to buffer (if in buffered mode), or immediately prints to stdout otherwise.'''
 

src/ssh_audit/ssh_audit.py

@@ -88,7 +88,7 @@ def usage(uout: OutputBuffer, err: Optional[str] = None) -> None:
     p = os.path.basename(sys.argv[0])
     uout.head('# {} {}, https://github.com/jtesta/ssh-audit\n'.format(p, VERSION))
     if err is not None and len(err) > 0:
-        uout.fail(err + '\n')
+        uout.error(err + '\n')
         retval = exitcodes.UNKNOWN_ERROR
     uout.info('usage: {0} [options] <host>\n'.format(p))
     uout.info('   -h,  --help             print this help')
@@ -835,7 +835,7 @@ def list_policies(out: OutputBuffer, verbose: bool) -> None:
 
     out.sep()
     if len(server_policy_names) == 0 and len(client_policy_names) == 0:
-        out.fail("Error: no built-in policies found!")
+        out.error("Error: no built-in policies found!")
     else:
         out.info("\nHint: Use -P and provide the full name of a policy to run a policy scan with.\n")
         out.info("Hint: Use -L -v to also see the change log for each policy.\n")
@@ -1051,19 +1051,19 @@ def process_commandline(out: OutputBuffer, args: List[str], usage_cb: Callable[.
             try:
                 aconf.policy = Policy(policy_file=aconf.policy_file, json_output=aconf.json)
             except Exception as e:
-                out.fail("Error while loading policy file: %s: %s" % (str(e), traceback.format_exc()))
+                out.error("Error while loading policy file: %s: %s" % (str(e), traceback.format_exc()))
                 out.write()
                 sys.exit(exitcodes.UNKNOWN_ERROR)
 
         # If the user wants to do a client audit, but provided a server policy, terminate.
         if aconf.client_audit and aconf.policy.is_server_policy():
-            out.fail("Error: client audit selected, but server policy provided.")
+            out.error("Error: client audit selected, but server policy provided.")
             out.write()
             sys.exit(exitcodes.UNKNOWN_ERROR)
 
         # If the user wants to do a server audit, but provided a client policy, terminate.
         if aconf.client_audit is False and aconf.policy.is_server_policy() is False:
-            out.fail("Error: server audit selected, but client policy provided.")
+            out.error("Error: server audit selected, but client policy provided.")
             out.write()
             sys.exit(exitcodes.UNKNOWN_ERROR)
 
@@ -1262,7 +1262,7 @@ def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print
         err = s.connect()
 
         if err is not None:
-            out.fail(err)
+            out.error(err)
 
             # If we're running against multiple targets, return a connection error to the calling worker thread.  Otherwise, write the error message to the console and exit.
             if len(aconf.target_list) > 0:
@@ -1310,7 +1310,7 @@ def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print
                 err = fmt.format(err_pair[0], err_pair[1], packet_type)
     if err is not None:
         output(out, aconf, banner, header)
-        out.fail(err)
+        out.error(err)
         return exitcodes.CONNECTION_ERROR
     if sshv == 1:
         program_retval = output(out, aconf, banner, header, pkm=SSH1_PublicKeyMessage.parse(payload))
@@ -1318,7 +1318,7 @@ def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print
         try:
             kex = SSH2_Kex.parse(out, payload)
         except Exception:
-            out.fail("Failed to parse server's kex.  Stack trace:\n%s" % str(traceback.format_exc()))
+            out.error("Failed to parse server's kex.  Stack trace:\n%s" % str(traceback.format_exc()))
             return exitcodes.CONNECTION_ERROR
 
         if aconf.dheat is not None:

src/ssh_audit/ssh_socket.py

@@ -108,7 +108,8 @@ class SSH_Socket(ReadBuf, WriteBuf):
             s.listen()
             self.__sock_map[s.fileno()] = s
         except Exception as e:
-            print("Warning: failed to listen on any IPv4 interfaces: %s" % str(e))
+            self.__outputbuffer.error("Warning: failed to listen on any IPv4 interfaces: %s" % str(e))
+            sys.exit(exitcodes.CONNECTION_ERROR)
 
         try:
             # Socket to listen on all IPv6 addresses.
@@ -119,11 +120,12 @@ class SSH_Socket(ReadBuf, WriteBuf):
             s.listen()
             self.__sock_map[s.fileno()] = s
         except Exception as e:
-            print("Warning: failed to listen on any IPv6 interfaces: %s" % str(e))
+            self.__outputbuffer.error("Warning: failed to listen on any IPv6 interfaces: %s" % str(e))
+            sys.exit(exitcodes.CONNECTION_ERROR)
 
         # If we failed to listen on any interfaces, terminate.
         if len(self.__sock_map.keys()) == 0:
-            print("Error: failed to listen on any IPv4 and IPv6 interfaces!")
+            self.__outputbuffer.error("Error: failed to listen on any IPv4 and IPv6 interfaces!")
             sys.exit(exitcodes.CONNECTION_ERROR)
 
         # Wait for an incoming connection.  If a timeout was explicitly
@@ -141,7 +143,7 @@ class SSH_Socket(ReadBuf, WriteBuf):
                 break
 
             if self.__timeout_set and time_elapsed >= self.__timeout:
-                print("Timeout elapsed.  Terminating...")
+                self.__outputbuffer.error("Timeout elapsed.  Terminating...")
                 sys.exit(exitcodes.CONNECTION_ERROR)
 
         # Accept the connection.
@@ -275,7 +277,7 @@ class SSH_Socket(ReadBuf, WriteBuf):
                 payload_length = packet_length - padding_length - 1
                 check_size = 4 + 1 + payload_length + padding_length
             if check_size % self.__block_size != 0:
-                self.__outputbuffer.fail('[exception] invalid ssh packet (block size)').write()
+                self.__outputbuffer.error('[exception] invalid ssh packet (block size)').write()
                 sys.exit(exitcodes.CONNECTION_ERROR)
             self.ensure_read(payload_length)
             if sshv == 1:
@@ -290,7 +292,7 @@ class SSH_Socket(ReadBuf, WriteBuf):
             if sshv == 1:
                 rcrc = SSH1.crc32(padding + payload)
                 if crc != rcrc:
-                    self.__outputbuffer.fail('[exception] packet checksum CRC32 mismatch.').write()
+                    self.__outputbuffer.error('[exception] packet checksum CRC32 mismatch.').write()
                     sys.exit(exitcodes.CONNECTION_ERROR)
             else:
                 self.ensure_read(padding_length)