2.1_rc8 and earlier did implicit shell expansion on script

arguments since all scripts were called by system().
The security hardening changes made to 2.1_rc9 no longer
use system(), but rather use the safer execve or CreateProcess
system calls.  The security hardening also introduced a
backward incompatibility with 2.1_rc8 and earlier in that
script parameters were no longer shell-expanded, so
for example:

  client-connect "docc CLIENT-CONNECT"

would fail to work because execve would try to execute
a script called "docc CLIENT-CONNECT" instead of "docc"
with "CLIENT-CONNECT" as the first argument.

This patch fixes the issue, bringing the script argument
semantics back to pre 2.1_rc9 behavior in order to preserve
backward compatibility while still using execve or CreateProcess
to execute the script/executable.


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@3311 e7ae566f-a301-0410-adde-c780ea21d3b5

1 files changed, 308 insertions, 70 deletions

diff --git a/misc.c b/misc.c
index 4cdc3de..45356a6 100644
--- a/misc.c
+++ b/misc.c
@@ -220,7 +220,7 @@ run_up_down (const char *command,
       ASSERT (arg);
       setenv_str (es, "script_type", script_type);
       argv_printf (&argv,
-		  "%s %s %d %d %s %s %s",
+		  "%sc %s %d %d %s %s %s",
 		  command,
 		  arg,
 		  tun_mtu, link_mtu,
@@ -1190,24 +1190,6 @@ absolute_pathname (const char *pathname)
     return false;
 }
 
-/*
- * Return the next largest power of 2
- * or u if u is a power of 2.
- */
-unsigned int
-adjust_power_of_2 (unsigned int u)
-{
-  unsigned int ret = 1;
-
-  while (ret < u)
-    {
-      ret <<= 1;
-      ASSERT (ret > 0);
-    }
-
-  return ret;
-}
-
 #ifdef HAVE_GETPASS
 
 static FILE *
@@ -1666,56 +1648,309 @@ openvpn_sleep (const int n)
   sleep (n);
 }
 
-#if 0
 /*
- * Configure PATH.  On Windows, sometimes PATH is not set correctly
- * by default.
+ * Return the next largest power of 2
+ * or u if u is a power of 2.
  */
+size_t
+adjust_power_of_2 (size_t u)
+{
+  size_t ret = 1;
+
+  while (ret < u)
+    {
+      ret <<= 1;
+      ASSERT (ret > 0);
+    }
+
+  return ret;
+}
+
+/*
+ * A printf-like function (that only recognizes a subset of standard printf
+ * format operators) that prints arguments to an argv list instead
+ * of a standard string.  This is used to build up argv arrays for passing
+ * to execve.
+ */
+
 void
-configure_path (void)
+argv_init (struct argv *a)
 {
-#ifdef WIN32
-  FILE *fp;
-  fp = fopen ("c:\\windows\\system32\\route.exe", "rb");
-  if (fp)
+  a->capacity = 0;
+  a->argc = 0;
+  a->argv = NULL;
+}
+
+struct argv
+argv_new (void)
+{
+  struct argv ret;
+  argv_init (&ret);
+  return ret;
+}
+
+void
+argv_reset (struct argv *a)
+{
+  size_t i;
+  for (i = 0; i < a->argc; ++i)
+    free (a->argv[i]);
+  free (a->argv);
+  argv_init (a);
+}
+
+static void
+argv_extend (struct argv *a, const size_t newcap)
+{
+  if (newcap > a->capacity)
     {
-      const int bufsiz = 4096;
-      struct gc_arena gc = gc_new ();
-      struct buffer oldpath = alloc_buf_gc (bufsiz, &gc);
-      struct buffer newpath = alloc_buf_gc (bufsiz, &gc);
-      const char* delim = ";";
-      DWORD status;
-      fclose (fp);
-      status = GetEnvironmentVariable ("PATH", BPTR(&oldpath), (DWORD)BCAP(&oldpath));
-#if 0
-      status = 0;
-#endif
-      if (!status)
+      char **newargv;
+      size_t i;
+      ALLOC_ARRAY_CLEAR (newargv, char *, newcap);
+      for (i = 0; i < a->argc; ++i)
+	newargv[i] = a->argv[i];
+      free (a->argv);
+      a->argv = newargv;
+      a->capacity = newcap;
+    }
+}
+
+static void
+argv_grow (struct argv *a, const size_t add)
+{
+  const size_t newargc = a->argc + add + 1;
+  ASSERT (newargc > a->argc);
+  argv_extend (a, adjust_power_of_2 (newargc));
+}
+
+static void
+argv_append (struct argv *a, char *str) /* str must have been malloced or be NULL */
+{
+  argv_grow (a, 1);
+  a->argv[a->argc++] = str;
+}
+
+struct argv
+argv_clone (const struct argv *a, const size_t headroom)
+{
+  struct argv r;
+  size_t i;
+
+  argv_init (&r);
+  for (i = 0; i < headroom; ++i)
+    argv_append (&r, NULL);
+  if (a)
+    {
+      for (i = 0; i < a->argc; ++i)
+	argv_append (&r, string_alloc (a->argv[i], NULL));
+    }
+  return r;
+}
+
+struct argv
+argv_insert_head (const struct argv *a, const char *head)
+{
+  struct argv r;
+
+  r = argv_clone (a, 1);
+  r.argv[0] = string_alloc (head, NULL);
+
+  return r;
+}
+
+char *
+argv_term (const char **f)
+{
+  const char *p = *f;
+  const char *term = NULL;
+  size_t termlen = 0;
+
+  if (*p == '\0')
+    return NULL;
+
+  while (true)
+    {
+      const int c = *p;
+      if (c == '\0')
+	break;
+      if (term)
 	{
-	  *BPTR(&oldpath) = '\0';
-	  delim = "";
+	  if (!isspace (c))
+	    ++termlen;
+	  else
+	    break;
 	}
-      buf_printf (&newpath, "C:\\WINDOWS\\System32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem%s%s",
-		  delim,
-		  BSTR(&oldpath));
-      SetEnvironmentVariable ("PATH", BSTR(&newpath));
-#if 0
-      status = GetEnvironmentVariable ("PATH", BPTR(&oldpath), (DWORD)BCAP(&oldpath));
-      if (status > 0)
-	printf ("PATH: %s\n", BSTR(&oldpath));
-#endif
-      gc_free (&gc);
+      else
+	{
+	  if (!isspace (c))
+	    {
+	      term = p;
+	      termlen = 1;
+	    }
+	}
+      ++p;
     }
-#endif
+  *f = p;
+
+  if (term)
+    {
+      char *ret;
+      ASSERT (termlen > 0);
+      ret = malloc (termlen + 1);
+      check_malloc_return (ret);
+      memcpy (ret, term, termlen);
+      ret[termlen] = '\0';
+      return ret;
+    }
+  else
+    return NULL;
+}
+
+const char *
+argv_str (const struct argv *a, struct gc_arena *gc, const unsigned int flags)
+{
+  if (a->argv)
+    return print_argv ((const char **)a->argv, gc, flags);
+  else
+    return "";
+}
+
+void
+argv_msg (const int msglev, const struct argv *a)
+{
+  struct gc_arena gc = gc_new ();
+  msg (msglev, "%s", argv_str (a, &gc, 0));
+  gc_free (&gc);
+}
+
+void
+argv_msg_prefix (const int msglev, const struct argv *a, const char *prefix)
+{
+  struct gc_arena gc = gc_new ();
+  msg (msglev, "%s: %s", prefix, argv_str (a, &gc, 0));
+  gc_free (&gc);
+}
+
+void
+argv_printf (struct argv *a, const char *format, ...)
+{
+  va_list arglist;
+  va_start (arglist, format);
+  argv_printf_arglist (a, format, 0, arglist);
+  va_end (arglist);
+ }
+
+void
+argv_printf_cat (struct argv *a, const char *format, ...)
+{
+  va_list arglist;
+  va_start (arglist, format);
+  argv_printf_arglist (a, format, APA_CAT, arglist);
+  va_end (arglist);
+}
+
+void
+argv_printf_arglist (struct argv *a, const char *format, const unsigned int flags, va_list arglist)
+{
+  struct gc_arena gc = gc_new ();
+  char *term;
+  const char *f = format;
+
+  if (!(flags & APA_CAT))
+    argv_reset (a);
+  argv_extend (a, 1); /* ensure trailing NULL */
+
+  while ((term = argv_term (&f)) != NULL) 
+    {
+      if (term[0] == '%')
+	{
+	  if (!strcmp (term, "%s"))
+	    {
+	      char *s = va_arg (arglist, char *);
+	      if (!s)
+		s = "";
+	      argv_append (a, string_alloc (s, NULL));
+	    }
+	  else if (!strcmp (term, "%sc"))
+	    {
+	      char *s = va_arg (arglist, char *);
+	      if (s)
+		{
+		  int nparms;
+		  char *parms[MAX_PARMS+1];
+		  int i;
+
+		  nparms = parse_line (s, parms, MAX_PARMS, "SCRIPT-ARGV", 0, M_FATAL, &gc);
+		  for (i = 0; i < nparms; ++i)
+		    argv_append (a, string_alloc (parms[i], NULL));
+		}
+	      else
+		argv_append (a, string_alloc ("", NULL));
+	    }
+	  else if (!strcmp (term, "%d"))
+	    {
+	      char numstr[64];
+	      openvpn_snprintf (numstr, sizeof (numstr), "%d", va_arg (arglist, int));
+	      argv_append (a, string_alloc (numstr, NULL));
+	    }
+	  else if (!strcmp (term, "%u"))
+	    {
+	      char numstr[64];
+	      openvpn_snprintf (numstr, sizeof (numstr), "%u", va_arg (arglist, unsigned int));
+	      argv_append (a, string_alloc (numstr, NULL));
+	    }
+	  else if (!strcmp (term, "%s/%d"))
+	    {
+	      char numstr[64];
+	      char *s = va_arg (arglist, char *);
+
+	      if (!s)
+		s = "";
+
+	      openvpn_snprintf (numstr, sizeof (numstr), "%d", va_arg (arglist, int));
+
+	      {
+		const size_t len = strlen(s) + strlen(numstr) + 2;
+		char *combined = (char *) malloc (len);
+		check_malloc_return (combined);
+
+		strcpy (combined, s);
+		strcat (combined, "/");
+		strcat (combined, numstr);
+		argv_append (a, combined);
+	      }
+	    }
+	  else if (!strcmp (term, "%s%s"))
+	    {
+	      char *s1 = va_arg (arglist, char *);
+	      char *s2 = va_arg (arglist, char *);
+	      char *combined;
+
+	      if (!s1) s1 = "";
+	      if (!s2) s2 = "";
+	      combined = (char *) malloc (strlen(s1) + strlen(s2) + 1);
+	      check_malloc_return (combined);
+	      strcpy (combined, s1);
+	      strcat (combined, s2);
+	      argv_append (a, combined);
+	    }
+	  else
+	    ASSERT (0);
+	  free (term);
+	}
+      else
+	{
+	  argv_append (a, term);
+	}
+    }
+  gc_free (&gc);
 }
-#endif
 
 #ifdef ARGV_TEST
 void
 argv_test (void)
 {
   struct gc_arena gc = gc_new ();
-  char line[512];
   const char *s;
 
   struct argv a;
@@ -1729,7 +1964,7 @@ argv_test (void)
 #endif
 
   argv_msg_prefix (M_INFO, &a, "ARGV");
-  openvpn_execve_check (&a, NULL, 0, "command failed");
+  //openvpn_execve_check (&a, NULL, 0, "command failed");
 
   argv_printf (&a, "this is a %s test of int %d unsigned %u", "FOO", -69, 42);
   s = argv_str (&a, &gc, PA_BRACKET);
@@ -1742,7 +1977,7 @@ argv_test (void)
     printf ("%s\n", s);
   }
 
-  argv_printf (&a, "foo bar %d", 99);
+  argv_printf (&a, "%sc foo bar %d", "\"multi term\" command      following \\\"spaces", 99);
   s = argv_str (&a, &gc, PA_BRACKET);
   argv_reset (&a);
   printf ("%s\n", s);
@@ -1752,25 +1987,28 @@ argv_test (void)
   printf ("%s\n", s);
 
   argv_printf (&a, "foo bar %d", 99);
-  argv_printf_cat (&a, "bar %d foo", 42);
+  argv_printf_cat (&a, "bar %d foo %sc", 42, "nonesuch");
   argv_printf_cat (&a, "cool %s %d u %s/%d end", "frood", 4, "hello", 7);
   s = argv_str (&a, &gc, PA_BRACKET);
   printf ("%s\n", s);
 
 #if 0
-  while (fgets (line, sizeof(line), stdin) != NULL)
-    {
-      char *term;
-      const char *f = line;
-      int i = 0;
-
-      while ((term = argv_term (&f)) != NULL) 
-	{
-	  printf ("[%d] '%s'\n", i, term);
-	  ++i;
-	  free (term);
-	}
-    }
+  {
+    char line[512];
+    while (fgets (line, sizeof(line), stdin) != NULL)
+      {
+	char *term;
+	const char *f = line;
+	int i = 0;
+
+	while ((term = argv_term (&f)) != NULL) 
+	  {
+	    printf ("[%d] '%s'\n", i, term);
+	    ++i;
+	    free (term);
+	  }
+      }
+  }
 #endif
 
   argv_reset (&a);