rhe	2016-12-20 14:26:08 +0900 (Tue, 20 Dec 2016)

  New Revision: 57119

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=57119

  Log:
    array.c: check array length every time after yielding
    
    Since the Array may be modified during rb_yield(), the length before
    invoking the block can't be trusted. Fix possible out-of-bounds read in
    Array#combination and Array#repeated_combination.
    
    It may better to make a defensive copy of the Array, but for now let's
    follow what Array#permutation does.  [ruby-core:78738] [Bug #13052]

  Modified files:
    trunk/array.c
    trunk/test/ruby/test_array.rb
Index: test/ruby/test_array.rb
===================================================================
--- test/ruby/test_array.rb	(revision 57118)
+++ test/ruby/test_array.rb	(revision 57119)
@@ -2483,11 +2483,18 @@ class TestArray < Test::Unit::TestCase https://github.com/ruby/ruby/blob/trunk/test/ruby/test_array.rb#L2483
 
   def test_combination_clear
     bug9939 = '[ruby-core:63149] [Bug #9939]'
-    assert_ruby_status([], <<-'end;', bug9939)
-      100_000.times {Array.new(1000)}
+    assert_nothing_raised(bug9939) {
       a = [*0..100]
       a.combination(3) {|*,x| a.clear}
-    end;
+    }
+
+    bug13052 = '[ruby-core:78738] [Bug #13052] Array#combination segfaults if the Array is modified during iteration'
+    assert_nothing_raised(bug13052) {
+      a = [*0..100]
+      a.combination(1) { a.clear }
+      a = [*0..100]
+      a.repeated_combination(1) { a.clear }
+    }
   end
 
   def test_product2
Index: array.c
===================================================================
--- array.c	(revision 57118)
+++ array.c	(revision 57119)
@@ -5194,7 +5194,7 @@ rb_ary_combination(VALUE ary, VALUE num) https://github.com/ruby/ruby/blob/trunk/array.c#L5194
 	rb_yield(rb_ary_new2(0));
     }
     else if (n == 1) {
-	for (i = 0; i < len; i++) {
+	for (i = 0; i < RARRAY_LEN(ary); i++) {
 	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
 	}
     }
@@ -5393,7 +5393,7 @@ rb_ary_repeated_combination(VALUE ary, V https://github.com/ruby/ruby/blob/trunk/array.c#L5393
 	rb_yield(rb_ary_new2(0));
     }
     else if (n == 1) {
-	for (i = 0; i < len; i++) {
+	for (i = 0; i < RARRAY_LEN(ary); i++) {
 	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
 	}
     }

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