3 files changed, 8 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index 0d5ac45c12..c9d34ed99d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Apr 20 14:41:28 2011  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* string.c (rb_str_each_line): check string's length when compare
+	  separator and string. [ruby-core:35815] fixes #4586
+
 Mon Apr 18 12:15:46 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/ruby/test_range.rb (TestRange#test_step_ruby_core_35753):
diff --git a/string.c b/string.c
index aa3029adbd..6f9fde11ce 100644
--- a/string.c
+++ b/string.c
@@ -5828,7 +5828,8 @@ rb_str_each_line(int argc, VALUE *argv, VALUE str)
 	    p -= n;
 	}
 	if (c == newline &&
-	    (rslen <= 1 || memcmp(RSTRING_PTR(rs), p, rslen) == 0)) {
+	    (rslen <= 1 ||
+	     (pend - p >= rslen && memcmp(RSTRING_PTR(rs), p, rslen) == 0))) {
 	    line = rb_str_new5(str, s, p - s + (rslen ? rslen : n));
 	    OBJ_INFECT(line, str);
 	    rb_enc_cr_str_copy_for_substr(line, str);
diff --git a/version.h b/version.h
index 43cfd7e371..bbeabfdb36 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #define RUBY_VERSION "1.9.2"
-#define RUBY_PATCHLEVEL 233
+#define RUBY_PATCHLEVEL 234
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1