random.c: Random.raw_seed

* random.c (random_raw_seed): extract platform dependent random
  seed initialization function as a new method Random.raw_seed.
* lib/securerandom.rb (SecureRandom): use Random.raw_seed.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49593 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 92 insertions, 104 deletions

diff --git a/ChangeLog b/ChangeLog
index 4bcd254803..feff938fd5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Sat Feb 14 12:01:32 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* random.c (random_raw_seed): extract platform dependent random
+	  seed initialization function as a new method Random.raw_seed.
+
+	* lib/securerandom.rb (SecureRandom): use Random.raw_seed.
+
 Sat Feb 14 00:49:37 2015  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/coverage/coverage.c: Add Coverage.peek_result.  Allows you to
diff --git a/lib/securerandom.rb b/lib/securerandom.rb
index 476f5e1233..96117e6976 100644
--- a/lib/securerandom.rb
+++ b/lib/securerandom.rb
@@ -47,56 +47,6 @@ end
 #
 
 module SecureRandom
-  if /mswin|mingw/ =~ RUBY_PLATFORM
-    require "fiddle/import"
-
-    module AdvApi32 # :nodoc:
-      extend Fiddle::Importer
-      dlload "advapi32"
-      extern "int CryptAcquireContext(void*, void*, void*, unsigned long, unsigned long)"
-      extern "int CryptGenRandom(void*, unsigned long, void*)"
-
-      def self.get_provider
-        hProvStr = " " * Fiddle::SIZEOF_VOIDP
-        prov_rsa_full = 1
-        crypt_verifycontext = 0xF0000000
-
-        if CryptAcquireContext(hProvStr, nil, nil, prov_rsa_full, crypt_verifycontext) == 0
-          raise SystemCallError, "CryptAcquireContext failed: #{lastWin32ErrorMessage}"
-        end
-        type = Fiddle::SIZEOF_VOIDP == Fiddle::SIZEOF_LONG_LONG ? 'q' : 'l'
-        hProv, = hProvStr.unpack(type)
-        hProv
-      end
-
-      def self.gen_random(n)
-        @hProv ||= get_provider
-        bytes = " ".force_encoding("ASCII-8BIT") * n
-        if CryptGenRandom(@hProv, bytes.size, bytes) == 0
-          raise SystemCallError, "CryptGenRandom failed: #{Kernel32.last_error_message}"
-        end
-        bytes
-      end
-    end
-
-    module Kernel32 # :nodoc:
-      extend Fiddle::Importer
-      dlload "kernel32"
-      extern "unsigned long GetLastError()"
-      extern "unsigned long FormatMessageA(unsigned long, void*, unsigned long, unsigned long, void*, unsigned long, void*)"
-
-      # Following code is based on David Garamond's GUID library for Ruby.
-      def self.last_error_message
-        format_message_ignore_inserts = 0x00000200
-        format_message_from_system    = 0x00001000
-
-        code = GetLastError()
-        msg = "\0" * 1024
-        len = FormatMessageA(format_message_ignore_inserts + format_message_from_system, 0, code, 0, msg, 1024, nil)
-        msg[0, len].force_encoding("filesystem").tr("\r", '').chomp
-      end
-    end
-  end
 
   # SecureRandom.random_bytes generates a random binary string.
   #
@@ -129,35 +79,16 @@ module SecureRandom
       end
       return OpenSSL::Random.random_bytes(n)
     end
-  elsif defined?(AdvApi32)
-    def self.gen_random(n)
-      return AdvApi32.gen_random(n)
-    end
-
-    def self.lastWin32ErrorMessage # :nodoc:
-      # for compatibility
-      return Kernel32.last_error_message
-    end
   else
     def self.gen_random(n)
-      flags = File::RDONLY
-      flags |= File::NONBLOCK if defined? File::NONBLOCK
-      flags |= File::NOCTTY if defined? File::NOCTTY
-      begin
-        File.open("/dev/urandom", flags) {|f|
-          unless f.stat.chardev?
-            break
-          end
-          ret = f.read(n)
-          unless ret.length == n
-            raise NotImplementedError, "Unexpected partial read from random device: only #{ret.length} for #{n} bytes"
-          end
-          return ret
-        }
-      rescue Errno::ENOENT
+      ret = Random.raw_seed(n)
+      unless ret
+        raise NotImplementedError, "No random device"
       end
-
-      raise NotImplementedError, "No random device"
+      unless ret.length == n
+        raise NotImplementedError, "Unexpected partial read from random device: only #{ret.length} for #{n} bytes"
+      end
+      ret
     end
   end
 
diff --git a/random.c b/random.c
index c03d613435..a179790115 100644
--- a/random.c
+++ b/random.c
@@ -84,6 +84,7 @@ The original copyright notice follows.
 #  undef __WINCRYPT_H__
 # endif
 #include <wincrypt.h>
+#include "ruby_atomic.h"
 #endif
 
 typedef int int_must_be_32bit_at_least[sizeof(int) * CHAR_BIT < 32 ? -1 : 1];
@@ -433,43 +434,75 @@ random_init(int argc, VALUE *argv, VALUE obj)
 # define USE_DEV_URANDOM 0
 #endif
 
+#if defined(_WIN32)
 static void
-fill_random_seed(uint32_t seed[DEFAULT_SEED_CNT])
+release_crypt(void *p)
 {
-    static int n = 0;
-    struct timeval tv;
-#if USE_DEV_URANDOM
-    int fd;
-    struct stat statbuf;
-#elif defined(_WIN32)
-    HCRYPTPROV prov;
+    HCRYPTPROV prov = (HCRYPTPROV)ATOMIC_PTR_EXCHANGE(*(HCRYPTPROV *)p, INVALID_HANDLE_VALUE);
+    if (prov && prov != (HCRYPTPROV)INVALID_HANDLE_VALUE) {
+	CryptReleaseContext(prov, 0);
+    }
+}
 #endif
 
-    memset(seed, 0, DEFAULT_SEED_LEN);
-
+static int
+fill_random_bytes(void *seed, size_t size)
+{
 #if USE_DEV_URANDOM
-    if ((fd = rb_cloexec_open("/dev/urandom", O_RDONLY
-#ifdef O_NONBLOCK
-            |O_NONBLOCK
-#endif
-#ifdef O_NOCTTY
-            |O_NOCTTY
-#endif
-            , 0)) >= 0) {
-        rb_update_max_fd(fd);
-        if (fstat(fd, &statbuf) == 0 && S_ISCHR(statbuf.st_mode)) {
-	    if (read(fd, seed, DEFAULT_SEED_LEN) < DEFAULT_SEED_LEN) {
-		/* abandon */;
-	    }
-        }
-        close(fd);
+    int fd = rb_cloexec_open("/dev/urandom",
+# ifdef O_NONBLOCK
+			     O_NONBLOCK|
+# endif
+# ifdef O_NOCTTY
+			     O_NOCTTY|
+# endif
+			     O_RDONLY, 0);
+    struct stat statbuf;
+    ssize_t ret = 0;
+
+    if (fd < 0) return -1;
+    rb_update_max_fd(fd);
+    if (fstat(fd, &statbuf) == 0 && S_ISCHR(statbuf.st_mode)) {
+	ret = read(fd, seed, size);
     }
+    close(fd);
+    if (ret < 0 || (size_t)ret < size) return -1;
 #elif defined(_WIN32)
-    if (CryptAcquireContext(&prov, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
-	CryptGenRandom(prov, DEFAULT_SEED_LEN, (void *)seed);
-	CryptReleaseContext(prov, 0);
+    static HCRYPTPROV perm_prov;
+    HCRYPTPROV prov = perm_prov, old_prov;
+    if (!prov) {
+	if (!CryptAcquireContext(&prov, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
+	    prov = (HCRYPTPROV)INVALID_HANDLE_VALUE;
+	}
+	old_prov = (HCRYPTPROV)ATOMIC_PTR_CAS(perm_prov, 0, prov);
+	if (prov == (HCRYPTPROV)INVALID_HANDLE_VALUE) {
+	    if (old_prov) prov = old_prov;
+	}
+	else {
+	    if (!old_prov) {
+		rb_gc_register_mark_object(Data_Wrap_Struct(0, 0, release_crypt, &prov));
+	    }
+	    else {
+		CryptReleaseContext(prov, 0);
+		prov = old_prov;
+	    }
+	}
     }
+    if (prov == (HCRYPTPROV)INVALID_HANDLE_VALUE) return -1;
+    CryptGenRandom(prov, size, seed);
 #endif
+    return 0;
+}
+
+static void
+fill_random_seed(uint32_t seed[DEFAULT_SEED_CNT])
+{
+    static int n = 0;
+    struct timeval tv;
+
+    memset(seed, 0, DEFAULT_SEED_LEN);
+
+    fill_random_bytes(seed, sizeof(*seed));
 
     gettimeofday(&tv, 0);
     seed[0] ^= tv.tv_usec;
@@ -525,6 +558,22 @@ random_seed(void)
 }
 
 /*
+ * call-seq: Random.raw_seed(size) -> string
+ *
+ * Returns a raw seed string, using platform providing features.
+ *
+ *   Random.raw_seed(8)  #=> "\x78\x41\xBA\xAF\x7D\xEA\xD8\xEA"
+ */
+static VALUE
+random_raw_seed(VALUE self, VALUE size)
+{
+    long n = NUM2ULONG(size);
+    VALUE buf = rb_str_new(0, n);
+    if (fill_random_bytes(RSTRING_PTR(buf), n)) return Qnil;
+    return buf;
+}
+
+/*
  * call-seq: prng.seed -> integer
  *
  * Returns the seed value used to initialize the generator. This may be used to
@@ -1380,6 +1429,7 @@ InitVM_Random(void)
     rb_define_singleton_method(rb_cRandom, "srand", rb_f_srand, -1);
     rb_define_singleton_method(rb_cRandom, "rand", random_s_rand, -1);
     rb_define_singleton_method(rb_cRandom, "new_seed", random_seed, 0);
+    rb_define_singleton_method(rb_cRandom, "raw_seed", random_raw_seed, 1);
     rb_define_private_method(CLASS_OF(rb_cRandom), "state", random_s_state, 0);
     rb_define_private_method(CLASS_OF(rb_cRandom), "left", random_s_left, 0);
 }