Merge pull request #2 from plutonium-dbg/feature/gdb-server-start-sus…

…pended suspend victim at launch
plutonium-dbg · Sep 16, 2018 · 8a299e0 · 8a299e0
2 parents 99cbc81 + 5aae052
commit 8a299e0
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Showing 3 changed files with 48 additions and 4 deletions.
diff --git a/clients/Makefile b/clients/Makefile
@@ -0,0 +1,6 @@
+.PHONY: all
+
+all: launch
+
+launch: launch.c
+	$(CC) $(CFLAGS) -o $@ $<
diff --git a/clients/gdbserver.py b/clients/gdbserver.py
@@ -23,10 +23,13 @@
 import logging
 import re
 import select
+import signal
 import socket
 import struct
 import subprocess
 import sys
+import time
+import os
 
 from binascii import hexlify, unhexlify
 from plutonium_dbg import debugger
@@ -157,8 +160,9 @@ def _query(request):
     if request.startswith('Supported'):
         return _q_supported(request)
     if request.startswith('Attached'):
-        for t in mod.enumerate_threads(tgid):
-           mod.suspend_thread(t)
+        # not necessary when using launcher, since victim is already suspended
+        # for t in mod.enumerate_threads(tgid):
+        #   mod.suspend_thread(t)
         return '1' # to indicate that we attached to a running process
     if request == 'C':
         return 'QC' + hex(tgid)[2:]
@@ -393,8 +397,12 @@ def main(program_args):
     sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     sock.bind(('', port))
 
-    # TODO: startup script
-    tgid = subprocess.Popen(program_args).pid
+    tgid = subprocess.Popen(["./launch", program_args]).pid
+    mod.set_event_mask(tgid, mod.EVENT_EXEC)
+    time.sleep(1) # TODO: get feedback from launch program
+    os.kill(tgid, signal.SIGUSR1) # signal that we're set up
+    mod.wait() # wait for exec event
+    mod.set_event_mask(tgid, mod.EVENT_SUSPEND)
 
     log.info('listening on :%d' % port)
     sock.listen(1)
@@ -413,5 +421,6 @@ def main(program_args):
     if len(sys.argv) < 2:
         print("Not enough arguments!")
         print("Usage: gdbserver.py victim-program")
+        exit(-1)
 
     main("".join(sys.argv[1:]))
diff --git a/clients/launch.c b/clients/launch.c
@@ -0,0 +1,29 @@
+#define _GNU_SOURCE
+#include <signal.h>
+#include <stdio.h>
+#include <unistd.h>
+
+sig_atomic_t received_signal = 0;
+
+void handle_sigusr1(int signal)
+{
+    received_signal = (signal == SIGUSR1);
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+    if (argc < 2)
+    {
+        fprintf(stderr, "Usage: %s command...\n", argv[0]);
+        return 1;
+    }
+
+    // Set up signal handler
+    signal(SIGUSR1, handle_sigusr1);
+
+    // Wait for SIGUSR1
+    while (!received_signal) usleep(50000);
+
+    // Launch target
+	execvpe(argv[1], &argv[1], envp);
+}