merge revision(s) 56938: [Backport #12988]

	Stop reading past the end of `ivptr` array

	If you have code like this:

	```ruby
	class A
  def initialize
    @a = nil
    @b = nil
    @c = nil
    @d = nil
    @e = nil
  end
	end

	x = A.new
	y = x.clone
	100.times { |z| x.instance_variable_set(:"@foo#{z}", nil) }
	puts y.inspect
	```

	`x` and `y` will share `iv_index_tbl` hashes.  However, the size of the
	hash will grow larger than the number if entries in `ivptr` in `y`.
	Before this commit, `rb_ivar_count` would use the size of the hash to
	determine how far to read in to the array, but this means that it could
	read past the end of the array and cause the program to segv

	[ruby-core:78403]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@57341 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 2 insertions, 2 deletions

diff --git a/variable.c b/variable.c
index 618aa852bd..2b8ee6672b 100644
--- a/variable.c
+++ b/variable.c
@@ -1605,7 +1605,7 @@ rb_ivar_count(VALUE obj)
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
 	if ((tbl = ROBJECT_IV_INDEX_TBL(obj)) != 0) {
-	    st_index_t i, count, num = tbl->num_entries;
+	    st_index_t i, count, num = ROBJECT_NUMIV(obj);
 	    const VALUE *const ivptr = ROBJECT_IVPTR(obj);
 	    for (i = count = 0; i < num; ++i) {
 		if (ivptr[i] != Qundef) {
diff --git a/version.h b/version.h
index 760766a397..c99d4abebb 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.3.3"
 #define RUBY_RELEASE_DATE "2017-01-17"
-#define RUBY_PATCHLEVEL 225
+#define RUBY_PATCHLEVEL 226
 
 #define RUBY_RELEASE_YEAR 2017
 #define RUBY_RELEASE_MONTH 1