Add ciphers option to bssl.

This simply converts a cipher suite string to the list of cipher suites
that it implies.

Change-Id: Id8b31086715d619ea6601c40a6eb84dc0d8c500d
Reviewed-on: https://boringssl-review.googlesource.com/6370
Reviewed-by: Adam Langley <agl@google.com>

tool/CMakeLists.txt

@@ -4,6 +4,7 @@ add_executable(
   bssl
 
   args.cc
+  ciphers.cc
   client.cc
   const.cc
   digest.cc

tool/ciphers.cc

@@ -0,0 +1,66 @@
+/* Copyright (c) 2015, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <string>
+#include <vector>
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include <openssl/ssl.h>
+
+#include "../crypto/test/scoped_types.h"
+#include "../ssl/test/scoped_types.h"
+#include "internal.h"
+
+
+bool Ciphers(const std::vector<std::string> &args) {
+  if (args.size() != 1) {
+    fprintf(stderr, "Usage: bssl ciphers <cipher suite string>\n");
+    return false;
+  }
+
+  const std::string &ciphers_string = args.back();
+
+  ScopedSSL_CTX ctx(SSL_CTX_new(SSLv23_client_method()));
+  if (!SSL_CTX_set_cipher_list(ctx.get(), ciphers_string.c_str())) {
+    fprintf(stderr, "Failed to parse cipher suite config.\n");
+    ERR_print_errors_fp(stderr);
+    return false;
+  }
+
+  const struct ssl_cipher_preference_list_st *pref_list = ctx->cipher_list;
+  STACK_OF(SSL_CIPHER) *ciphers = pref_list->ciphers;
+
+  bool last_in_group = false;
+  for (size_t i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
+    bool in_group = pref_list->in_group_flags[i];
+    const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);
+
+    if (in_group && !last_in_group) {
+      printf("[\n  ");
+    } else if (last_in_group) {
+      printf("  ");
+    }
+
+    printf("%s\n", SSL_CIPHER_get_name(cipher));
+
+    if (!in_group && last_in_group) {
+      printf("]\n");
+    }
+    last_in_group = in_group;
+  }
+
+  return true;
+}

tool/tool.cc

@@ -27,6 +27,7 @@
 #endif
 
 
+bool Ciphers(const std::vector<std::string> &args);
 bool Client(const std::vector<std::string> &args);
 bool DoPKCS12(const std::vector<std::string> &args);
 bool GenerateRSAKey(const std::vector<std::string> &args);
@@ -48,6 +49,7 @@ struct Tool {
 };
 
 static const Tool kTools[] = {
+  { "ciphers", Ciphers },
   { "client", Client },
   { "genrsa", GenerateRSAKey },
   { "md5sum", MD5Sum },