normal	2016-08-07 06:50:10 +0900 (Sun, 07 Aug 2016)

  New Revision: 55822

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=55822

  Log:
    openssl: avoid undefined behavior on empty SSL_write
    
    SSL_write(3ssl) manpage has this in the WARNINGS section:
    
           When calling SSL_write() with num=0 bytes to be sent the
           behaviour is undefined.
    
    And indeed, the new test case demonstrates failures when
    empty strings are used.  So, match the behavior of IO#write,
    IO#write_nonblock, and IO#syswrite by returning zero, as the
    OpenSSL::SSL::SSLSocket API already closely mimics the IO one.
    
    * ext/openssl/ossl_ssl.c (ossl_ssl_write_internal):
      avoid undefined behavior
    * test/openssl/test_pair.rb (test_write_zero): new test
      [ruby-core:76751] [Bug #12660]

  Modified files:
    trunk/ChangeLog
    trunk/ext/openssl/ossl_ssl.c
    trunk/test/openssl/test_pair.rb
Index: ext/openssl/ossl_ssl.c
===================================================================
--- ext/openssl/ossl_ssl.c	(revision 55821)
+++ ext/openssl/ossl_ssl.c	(revision 55822)
@@ -1744,7 +1744,13 @@ ossl_ssl_write_internal(VALUE self, VALU https://github.com/ruby/ruby/blob/trunk/ext/openssl/ossl_ssl.c#L1744
 
     if (ssl_started(ssl)) {
 	for (;;){
-	    nwrite = SSL_write(ssl, RSTRING_PTR(str), RSTRING_LENINT(str));
+	    int num = RSTRING_LENINT(str);
+
+	    /* SSL_write(3ssl) manpage states num == 0 is undefined */
+	    if (num == 0)
+		goto end;
+
+	    nwrite = SSL_write(ssl, RSTRING_PTR(str), num);
 	    switch(ssl_get_error(ssl, nwrite)){
 	    case SSL_ERROR_NONE:
 		goto end;
Index: test/openssl/test_pair.rb
===================================================================
--- test/openssl/test_pair.rb	(revision 55821)
+++ test/openssl/test_pair.rb	(revision 55822)
@@ -311,6 +311,17 @@ module OpenSSL::TestPairM https://github.com/ruby/ruby/blob/trunk/test/openssl/test_pair.rb#L311
     }
   end
 
+  def test_write_zero
+    ssl_pair {|s1, s2|
+      assert_equal 0, s2.write_nonblock('', exception: false)
+      assert_kind_of Symbol, s1.read_nonblock(1, exception: false)
+      assert_equal 0, s2.syswrite('')
+      assert_kind_of Symbol, s1.read_nonblock(1, exception: false)
+      assert_equal 0, s2.write('')
+      assert_kind_of Symbol, s1.read_nonblock(1, exception: false)
+    }
+  end
+
   def tcp_pair
     host = "127.0.0.1"
     serv = TCPServer.new(host, 0)
Index: ChangeLog
===================================================================
--- ChangeLog	(revision 55821)
+++ ChangeLog	(revision 55822)
@@ -1,3 +1,10 @@ https://github.com/ruby/ruby/blob/trunk/ChangeLog#L1
+Sun Aug  7 06:48:21 2016  Eric Wong  <e@8...>
+
+	* ext/openssl/ossl_ssl.c (ossl_ssl_write_internal):
+	  avoid undefined behavior
+	* test/openssl/test_pair.rb (test_write_zero): new test
+	  [ruby-core:76751] [Bug #12660]
+
 Sat Aug  6 09:35:30 2016  Nobuyoshi Nakada  <nobu@r...>
 
 	* id_table.h (rb_id_table_iterator_result): add dummy sentinel

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