random.c: coerce before check negative

* random.c (rb_random_ulong_limited): coerce before check negative.
  [Fixes GH-379]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42542 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 32 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 475cc3f9e6..c11db0171f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Aug 13 22:12:59 2013  Kenichi Kamiya  <kachick1@gmail.com>
+
+	* random.c (rb_random_ulong_limited): coerce before check negative.
+	  [Fixes GH-379]
+
 Tue Aug 13 21:52:15 2013  Kenichi Kamiya  <kachick1@gmail.com>
 
 	* object.c (Init_Object): undef Module#prepend_features on Class, as
diff --git a/random.c b/random.c
index 6a42e24f34..cfd2f6275a 100644
--- a/random.c
+++ b/random.c
@@ -851,7 +851,7 @@ rb_random_ulong_limited(VALUE obj, unsigned long limit)
     if (!rnd) {
 	extern int rb_num_negative_p(VALUE);
 	VALUE lim = ulong_to_num_plus_1(limit);
-	VALUE v = rb_funcall2(obj, id_rand, 1, &lim);
+	VALUE v = rb_to_int(rb_funcall2(obj, id_rand, 1, &lim));
 	unsigned long r = NUM2ULONG(v);
 	if (rb_num_negative_p(v)) {
 	    rb_raise(rb_eRangeError, "random number too small %ld", r);
diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 5123ab5a94..b4f35af84d 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -2044,6 +2044,19 @@ class TestArray < Test::Unit::TestCase
       alias rand call
     end
     assert_raise(RuntimeError) {ary.shuffle!(random: gen)}
+
+    zero = Object.new
+    def zero.to_int
+      0
+    end
+    gen_to_int = proc do |max|
+      zero
+    end
+    class << gen_to_int
+      alias rand call
+    end
+    ary = (0...10000).to_a
+    assert_equal(ary.rotate, ary.shuffle(random: gen_to_int))
   end
 
   def test_sample
@@ -2127,6 +2140,19 @@ class TestArray < Test::Unit::TestCase
     assert_equal([5000, 0, 5001, 2, 5002, 4, 5003, 6, 5004, 8, 5005], ary.sample(11, random: gen0))
     ary.sample(11, random: gen1) # implementation detail, may change in the future
     assert_equal([], ary)
+
+    half = Object.new
+    def half.to_int
+      5000
+    end
+    gen_to_int = proc do |max|
+      half
+    end
+    class << gen_to_int
+      alias rand call
+    end
+    ary = (0...10000).to_a
+    assert_equal(5000, ary.sample(random: gen_to_int))
   end
 
   def test_cycle