From 40e903c8e0a925df1c67eec6fbd1be6ffccd0f09 Mon Sep 17 00:00:00 2001
From: Rob Austein <sra@hactrn.net>
Date: Thu, 7 Jul 2016 15:05:37 -0400
Subject: Rewrite and add cleanup sequences to avoid confusing the RPC server.

---
 projects/hsm/cryptech_probe | 88 +++++++++++++++++++++++----------------------
 1 file changed, 45 insertions(+), 43 deletions(-)

diff --git a/projects/hsm/cryptech_probe b/projects/hsm/cryptech_probe
index 16a2a8f..bc798bc 100755
--- a/projects/hsm/cryptech_probe
+++ b/projects/hsm/cryptech_probe
@@ -38,8 +38,15 @@ import time
 import argparse
 import serial.tools.list_ports_posix
 
+class positive_integer(int):
+    def __init__(self, value):
+        if self <= 0:
+            raise ValueError
+
 parser = argparse.ArgumentParser(formatter_class = argparse.ArgumentDefaultsHelpFormatter)
-parser.add_argument("-v", "--verbose", action = "store_true", help = "blather about what we're doing")
+parser.add_argument("-v", "--verbose", action = "store_true",   help = "blather about what we're doing")
+parser.add_argument("--no-cleanup",    action = "store_true",   help = "don't send cleanup sequences after probing")
+parser.add_argument("--read-size",     type = positive_integer, help = "size of read buffer", default = 1024)
 args = parser.parse_args()
 
 SLIP_END     = chr(0300)        # Indicates end of SLIP packet
@@ -65,30 +72,8 @@ RPC_reply    = chr(0) * 12      # opcode = RPC_FUNC_GET_VERSION, client_handle =
 
 probe_string = SLIP_END + Control_U + SLIP_END + RPC_query + SLIP_END + Control_U + Control_M
 
-def looks_like_console(response):
-    # Check whether we got a known console prompt.
-    return any(prompt in response for prompt in ("Username:", "Password:", "cryptech>"))
-
-
-def looks_like_rpc(response):
-    # Check whether we got something that looks like the response to an RPC version query.
-    # We skip over the version value itself, as it might change, but we check that it's
-    # terminated properly.  This is fragile, and will need to handle SLIP decoding if
-    # we ever bump one of the version fields up into the range where the SLIP control
-    # characters live, but it will do for the moment.
-    try:
-        return response[response.index(SLIP_END + RPC_reply) + len(SLIP_END + RPC_reply) + 4] == SLIP_END
-    except ValueError:
-        return False
-    except IndexError:
-        return False
-
-
-rpc_hints    = None
-
-ports = dict((port, None)
-             for port, desc, hwid in serial.tools.list_ports_posix.comports()
-             if "VID:PID=0403:6014" in hwid)
+ports = [port for port, desc, hwid in serial.tools.list_ports_posix.comports()
+         if "VID:PID=0403:6014" in hwid]
 
 if not ports:
     sys.exit("Couldn't find any likely USB ports")
@@ -97,33 +82,50 @@ if args.verbose:
     print "Candidate USB ports:", ", ".join(ports)
 
 for port in ports:
+
     while True:
         try:
-            ports[port] = serial.Serial(port, 921600, timeout=0.1)
+            tty = serial.Serial(port, 921600, timeout=0.1)
             break
         except serial.SerialException:
             time.sleep(0.2)
 
-for port in ports:
-    # Do we really need to dole out characters one at a time here?
-    # Dunno, but this works well enough.
     for c in probe_string:
-        ports[port].write(c)
+        tty.write(c)
         time.sleep(0.1)
 
-time.sleep(1)
-
-for port in ports:
-    s = ""
-    while True:
-        c = ports[port].read(1)
-        if len(c) > 0:
-            s += c
-        else:
-            break
+    response = tty.read(args.read_size)
     if args.verbose:
-        print "Received from {}: {!r} ({})".format(port, s, ":".join("{:02x}".format(ord(c)) for c in s))
-    if looks_like_console(s):
+        print "Received from {}: {!r} ({})".format(port, response, ":".join("{:02x}".format(ord(c)) for c in response))
+
+    # Check whether we got a known console prompt.
+
+    is_cty = any(prompt in response for prompt in ("Username:", "Password:", "cryptech>"))
+
+    # Check whether we got something that looks like the response to an RPC version query.
+    # We skip over the version value itself, as it might change, but we check that it's
+    # terminated properly.  This is fragile, and will need to handle SLIP decoding if
+    # we ever bump one of the version fields up into the range where the SLIP control
+    # characters live, but it will do for the moment.
+
+    try:
+        is_hsm = response[response.index(SLIP_END + RPC_reply) + len(SLIP_END + RPC_reply) + 4] == SLIP_END
+    except ValueError:
+        is_hsm = False
+    except IndexError:
+        is_hsm = False
+
+    if is_cty:
         print "{} looks like the Cryptech HSM console port".format(port)
-    if looks_like_rpc(s):
+    if is_hsm:
         print "{} looks like the Cryptech HSM RPC port".format(port)
+
+    if (is_cty or is_hsm) and not args.no_cleanup:
+        if is_cty:
+            tty.write(Control_U)
+        if is_hsm:
+            tty.write(SLIP_END)
+        while tty.read(args.read_size):
+            pass
+
+    tty.close()
-- 
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