--random-file

While working on SSL options, I noticed that we were using insecure
random seeding by default.  This patch introduces a --random-file
option, a la curl, which may be used to select an explicit file with
external randomness.  This patch disables insecure seeds (leaving them
ifdeffed out in the code), but hints the user to use --random-file
when seeding is a problem.

The patch also makes Wget exit upon encountering serious problems with
certificates and such.  It makes little sense to keep going in that
case, even when a warning is printed.  Think Jan Minar.  :-)

The certificate validation code is still badly in need of auditing.
Anyone?

The patch should not affect non-SSL usage.  Update to the manual
follows RSN.


2005-04-27  Hrvoje Niksic  <[email protected]>

	* openssl.c (init_prng): Disable the weak random seed by default.

	* http.c (gethttp): Simplify SSL initialization; disable SSL when
	anything goes wrong with the initialization.

	* options.h (struct options): New option opt.random_file.

Index: src/http.c
===================================================================
RCS file: /pack/anoncvs/wget/src/http.c,v
retrieving revision 1.168
diff -u -r1.168 http.c
--- src/http.c	2005/04/27 17:15:09	1.168
+++ src/http.c	2005/04/27 21:02:31
@@ -1187,29 +1187,12 @@
     {
       /* Initialize the SSL context.  After this has once been done,
 	 it becomes a no-op.  */
-      switch (ssl_init ())
+      if (!ssl_init ())
 	{
-	case SSLERRCTXCREATE:
-	  /* this is fatal */
-	  logprintf (LOG_NOTQUIET, _("Failed to set up an SSL context\n"));
-	  return SSLERRCTXCREATE;
-	case SSLERRCERTFILE:
-	  /* try without certfile */
+	  scheme_disable (SCHEME_HTTPS);
 	  logprintf (LOG_NOTQUIET,
-		     _("Failed to load certificates from %s\n"),
-		     opt.cert_file);
-	  logprintf (LOG_NOTQUIET,
-		     _("Trying without the specified certificate\n"));
-	  break;
-	case SSLERRCERTKEY:
-	  logprintf (LOG_NOTQUIET,
-		     _("Failed to get private key from %s\n"),
-		     opt.private_key);
-	  logprintf (LOG_NOTQUIET,
-		     _("Trying without the specified certificate\n"));
-	  break;
-	default:
-	  break;
+		     _("Disabling SSL due to encountered errors.\n"));
+	  return SSLINITFAILED;
 	}
     }
 #endif /* HAVE_SSL */
@@ -2232,7 +2215,7 @@
 	  continue;
 	  break;
 	case HOSTERR: case CONIMPOSSIBLE: case PROXERR: case AUTHFAILED: 
-	case SSLERRCTXCREATE: case CONTNOTSUPPORTED:
+	case SSLINITFAILED: case CONTNOTSUPPORTED:
 	  /* Fatal errors just return from the function.  */
 	  free_hstat (&hstat);
 	  xfree_null (dummy);
Index: src/init.c
===================================================================
RCS file: /pack/anoncvs/wget/src/init.c,v
retrieving revision 1.106
diff -u -r1.106 init.c
--- src/init.c	2005/04/27 18:27:57	1.106
+++ src/init.c	2005/04/27 21:02:33
@@ -205,6 +205,7 @@
   { "proxyuser",	&opt.proxy_user,	cmd_string },
   { "quiet",		&opt.quiet,		cmd_boolean },
   { "quota",		&opt.quota,		cmd_bytes_large },
+  { "randomfile",	&opt.random_file,	cmd_file },
   { "randomwait",	&opt.random_wait,	cmd_boolean },
   { "readtimeout",	&opt.read_timeout,	cmd_time },
   { "reclevel",		&opt.reclevel,		cmd_number_inf },
Index: src/main.c
===================================================================
RCS file: /pack/anoncvs/wget/src/main.c,v
retrieving revision 1.130
diff -u -r1.130 main.c
--- src/main.c	2005/04/27 17:15:10	1.130
+++ src/main.c	2005/04/27 21:02:35
@@ -231,6 +231,7 @@
     { "proxy-user", 0, OPT_VALUE, "proxyuser", -1 },
     { "quiet", 'q', OPT_BOOLEAN, "quiet", -1 },
     { "quota", 'Q', OPT_VALUE, "quota", -1 },
+    { "random-file", 0, OPT_VALUE, "randomfile", -1 },
     { "random-wait", 0, OPT_BOOLEAN, "randomwait", -1 },
     { "read-timeout", 0, OPT_VALUE, "readtimeout", -1 },
     { "recursive", 'r', OPT_BOOLEAN, "recursive", -1 },
@@ -552,7 +553,9 @@
     N_("\
        --ca-directory=DIR       directory where hash list of CA's is stored.\n"),
     N_("\
-       --egd-file=FILE          file name of the EGD socket.\n"),
+       --random-file=FILE       file with random data for seeding the SSL PRNG.\n"),
+    N_("\
+       --egd-file=FILE          file naming the EGD socket with random data.\n"),
     "\n",
 #endif /* HAVE_SSL */
 
Index: src/openssl.c
===================================================================
RCS file: /pack/anoncvs/wget/src/openssl.c,v
retrieving revision 1.2
diff -u -r1.2 openssl.c
--- src/openssl.c	2005/04/27 17:15:10	1.2
+++ src/openssl.c	2005/04/27 21:02:35
@@ -59,29 +59,43 @@
 extern int errno;
 #endif
 
+/* Application-wide SSL context.  This is common to all SSL
+   connections.  */
 SSL_CTX *ssl_ctx;
 
+/* Initialize the SSL's PRNG using various methods. */
+
 static void
-ssl_init_prng (void)
+init_prng (void)
 {
-  /* It is likely that older versions of OpenSSL will fail on
-     non-Linux machines because this code is unable to seed the PRNG
-     on older versions of the library.  */
-
-#if SSLEAY_VERSION_NUMBER >= 0x00905100
-  char rand_file[256];
-
-  /* First, seed from a file specified by the user.  This will be
-     $RANDFILE, if set, or ~/.rnd.  */
-  RAND_file_name (rand_file, sizeof (rand_file));
-  if (rand_file)
-    /* Seed at most 16k (value borrowed from curl) from random file. */
-    RAND_load_file (rand_file, 16384);
+  char namebuf[256];
+  const char *random_file;
+
+  if (RAND_status ())
+    /* The PRNG has been seeded; no further action is necessary. */
+    return;
+
+  /* Seed from a file specified by the user.  This will be the file
+     specified with --random-file, $RANDFILE, if set, or ~/.rnd, if it
+     exists.  */
+  if (opt.random_file)
+    random_file = opt.random_file;
+  else
+    {
+      /* Get the random file name using RAND_file_name. */
+      namebuf[0] = '\0';
+      random_file = RAND_file_name (namebuf, sizeof (namebuf));
+    }
+
+  if (random_file && *random_file)
+    /* Seed at most 16k (apparently arbitrary value borrowed from
+       curl) from random file. */
+    RAND_load_file (random_file, 16384);
 
   if (RAND_status ())
     return;
 
-  /* Get random data from EGD if opt.egd_file was set.  */
+  /* Get random data from EGD if opt.egd_file was used.  */
   if (opt.egd_file && *opt.egd_file)
     RAND_egd (opt.egd_file);
 
@@ -107,7 +121,7 @@
        PRNG.  This is cryptographically weak and defeats the purpose
        of using OpenSSL, which is why it is highly discouraged.  */
 
-    logprintf (LOG_VERBOSE, _("WARNING: using a weak random seed.\n"));
+    logprintf (LOG_NOTQUIET, _("WARNING: using a weak random seed.\n"));
 
     while (RAND_status () == 0 && maxrand-- > 0)
       {
@@ -116,16 +130,17 @@
       }
   }
 #endif
-
-#endif /* SSLEAY_VERSION_NUMBER >= 0x00905100 */
 }
 
+/* #### Someone should audit and document this. */
+
 static int
 verify_callback (int ok, X509_STORE_CTX *ctx)
 {
-  char *s, buf[256];
-  s = X509_NAME_oneline (X509_get_subject_name (ctx->current_cert),
-			 buf, sizeof (buf));
+  char buf[256];
+  /* #### Why are we not using the result of this call? */
+  X509_NAME_oneline (X509_get_subject_name (ctx->current_cert),
+		     buf, sizeof (buf));
   if (ok == 0)
     {
       switch (ctx->error)
@@ -144,10 +159,10 @@
   return ok;
 }
 
-/* Print SSL errors. */
+/* Print errors in the OpenSSL error stack. */
 
 static void
-ssl_print_errors (void) 
+print_errors (void) 
 {
   unsigned long curerr = 0;
   while ((curerr = ERR_get_error ()) != 0)
@@ -173,30 +188,35 @@
       abort ();
     }
 }
+
+/* Create an SSL Context and set default paths etc.  Called the first
+   time an HTTP download is attempted.
+
+   Returns 0 on success, non-zero otherwise.  */
 
-/* Creates a SSL Context and sets some defaults for it */
-uerr_t
+int
 ssl_init ()
 {
-  SSL_METHOD *meth = NULL;
+  SSL_METHOD *meth;
 
   if (ssl_ctx)
-    return 0;
+    /* The SSL has already been initialized. */
+    return 1;
 
   /* Init the PRNG.  If that fails, bail out.  */
-  ssl_init_prng ();
-  if (RAND_status () == 0)
+  init_prng ();
+  if (RAND_status () != 1)
     {
       logprintf (LOG_NOTQUIET,
-		 _("Could not seed OpenSSL PRNG; disabling SSL.\n"));
-      scheme_disable (SCHEME_HTTPS);
-      return SSLERRCTXCREATE;
+		 _("Could not seed PRNG; consider using --random-file.\n"));
+      goto error;
     }
 
   SSL_library_init ();
   SSL_load_error_strings ();
   SSLeay_add_all_algorithms ();
   SSLeay_add_ssl_algorithms ();
+
   switch (opt.secure_protocol)
     {
     case secure_protocol_auto:
@@ -216,6 +236,9 @@
     }
 
   ssl_ctx = SSL_CTX_new (meth);
+  if (!ssl_ctx)
+    goto error;
+
   SSL_CTX_set_default_verify_paths (ssl_ctx);
   SSL_CTX_load_verify_locations (ssl_ctx, opt.ca_cert, opt.ca_directory);
   SSL_CTX_set_verify (ssl_ctx,
@@ -226,24 +249,24 @@
     if (SSL_CTX_use_certificate_file (ssl_ctx, opt.cert_file,
 				      key_type_to_ssl_type (opt.cert_type))
 	!= 1)
-      {
-	ssl_print_errors ();
-	return SSLERRCERTFILE;
-      }
+      goto error;
   if (opt.private_key)
     if (SSL_CTX_use_PrivateKey_file (ssl_ctx, opt.private_key,
 				     key_type_to_ssl_type (opt.private_key_type))
 	!= 1)
-      {
-	ssl_print_errors ();
-	return SSLERRCERTKEY;
-      }
+      goto error;
 
-  return 0; /* Succeded */
+  return 1;
+
+ error:
+  if (ssl_ctx)
+    SSL_CTX_free (ssl_ctx);
+  print_errors ();
+  return 0;
 }
 
 static int
-ssl_read (int fd, char *buf, int bufsize, void *ctx)
+openssl_read (int fd, char *buf, int bufsize, void *ctx)
 {
   int ret;
   SSL *ssl = (SSL *) ctx;
@@ -256,7 +279,7 @@
 }
 
 static int
-ssl_write (int fd, char *buf, int bufsize, void *ctx)
+openssl_write (int fd, char *buf, int bufsize, void *ctx)
 {
   int ret = 0;
   SSL *ssl = (SSL *) ctx;
@@ -269,7 +292,7 @@
 }
 
 static int
-ssl_poll (int fd, double timeout, int wait_for, void *ctx)
+openssl_poll (int fd, double timeout, int wait_for, void *ctx)
 {
   SSL *ssl = (SSL *) ctx;
   if (timeout == 0)
@@ -280,7 +303,7 @@
 }
 
 static int
-ssl_peek (int fd, char *buf, int bufsize, void *ctx)
+openssl_peek (int fd, char *buf, int bufsize, void *ctx)
 {
   int ret;
   SSL *ssl = (SSL *) ctx;
@@ -293,7 +316,7 @@
 }
 
 static void
-ssl_close (int fd, void *ctx)
+openssl_close (int fd, void *ctx)
 {
   SSL *ssl = (SSL *) ctx;
   SSL_shutdown (ssl);
@@ -332,16 +355,16 @@
 
   /* Register FD with Wget's transport layer, i.e. arrange that
      SSL-enabled functions are used for reading, writing, and polling.
-     That way the rest of Wget can keep using xread, xwrite, and
+     That way the rest of Wget can keep using fd_read, fd_write, and
      friends and not care what happens underneath.  */
-  fd_register_transport (fd, ssl_read, ssl_write, ssl_poll, ssl_peek,
-			 ssl_close, ssl);
+  fd_register_transport (fd, openssl_read, openssl_write, openssl_poll,
+			 openssl_peek, openssl_close, ssl);
   DEBUGP (("Connected %d to SSL 0x%0*lx\n", fd, 2 * sizeof (void *),
 	   (unsigned long) ssl));
   return 1;
 
  err:
-  ssl_print_errors ();
+  print_errors ();
   if (ssl)
     SSL_free (ssl);
   return 0;
Index: src/options.h
===================================================================
RCS file: /pack/anoncvs/wget/src/options.h,v
retrieving revision 1.50
diff -u -r1.50 options.h
--- src/options.h	2005/04/27 17:15:10	1.50
+++ src/options.h	2005/04/27 21:02:36
@@ -179,6 +179,7 @@
   char *ca_cert;		/* CA certificate file to use */
 
 
+  char *random_file;		/* file with random data to seed the PRNG */
   char *egd_file;		/* file name of the egd daemon socket */
 #endif /* HAVE_SSL */
 
Index: src/ssl.h
===================================================================
RCS file: /pack/anoncvs/wget/src/ssl.h,v
retrieving revision 1.1
diff -u -r1.1 ssl.h
--- src/ssl.h	2005/04/26 21:41:38	1.1
+++ src/ssl.h	2005/04/27 21:02:36
@@ -31,7 +31,7 @@
 #ifndef GEN_SSLFUNC_H
 #define GEN_SSLFUNC_H
 
-uerr_t ssl_init PARAMS ((void));
+int ssl_init PARAMS ((void));
 int ssl_connect PARAMS ((int));
 
 #endif /* GEN_SSLFUNC_H */
Index: src/wget.h
===================================================================
RCS file: /pack/anoncvs/wget/src/wget.h,v
retrieving revision 1.56
diff -u -r1.56 wget.h
--- src/wget.h	2005/04/10 19:54:02	1.56
+++ src/wget.h	2005/04/27 21:02:36
@@ -252,8 +252,7 @@
   CONTNOTSUPPORTED, RETRUNNEEDED, RETRFINISHED, READERR, TRYLIMEXC,
   URLBADPATTERN, FILEBADFILE, RANGEERR, RETRBADPATTERN,
   RETNOTSUP, ROBOTSOK, NOROBOTS, PROXERR, AUTHFAILED,
-  QUOTEXC, WRITEFAILED,
-  SSLERRCERTFILE,SSLERRCERTKEY,SSLERRCTXCREATE
+  QUOTEXC, WRITEFAILED, SSLINITFAILED
 } uerr_t;
 
 #endif /* WGET_H */