Fix for bug#57272: crash in rpad() when using utf8

Problem: if multibyte and binary string arguments passed to 
RPAD(), LPAD() or INSERT() functions, they might return 
wrong results or even lead to a server crash due to missed
character set convertion.

Fix: perform the convertion if necessary.

mysql-test/r/ctype_utf8.result

@@ -1898,3 +1898,34 @@ CONVERT(a, CHAR)	CONVERT(b, CHAR)
 70000	1092
 DROP TABLE t1;
 End of 5.0 tests
+SELECT LENGTH(RPAD(0.0115E88, 61297, _utf8'яэюя'));
+LENGTH(RPAD(0.0115E88, 61297, _utf8'яэюя'))
+61297
+SELECT LENGTH(RPAD(0.0115E88, 61297, _utf8'йцуя'));
+LENGTH(RPAD(0.0115E88, 61297, _utf8'йцуя'))
+61297
+SELECT HEX(RPAD(0x20, 2, _utf8 0xD18F));
+HEX(RPAD(0x20, 2, _utf8 0xD18F))
+20D1
+SELECT HEX(RPAD(0x20, 4, _utf8 0xD18F));
+HEX(RPAD(0x20, 4, _utf8 0xD18F))
+20D18FD1
+SELECT HEX(LPAD(0x20, 2, _utf8 0xD18F));
+HEX(LPAD(0x20, 2, _utf8 0xD18F))
+D120
+SELECT HEX(LPAD(0x20, 4, _utf8 0xD18F));
+HEX(LPAD(0x20, 4, _utf8 0xD18F))
+D18FD120
+SELECT HEX(RPAD(_utf8 0xD18F, 3, 0x20));
+HEX(RPAD(_utf8 0xD18F, 3, 0x20))
+D18F20
+SELECT HEX(LPAD(_utf8 0xD18F, 3, 0x20));
+HEX(LPAD(_utf8 0xD18F, 3, 0x20))
+20D18F
+SELECT HEX(INSERT(_utf8 0xD18F, 2, 1, 0x20));
+HEX(INSERT(_utf8 0xD18F, 2, 1, 0x20))
+D120
+SELECT HEX(INSERT(_utf8 0xD18FD18E, 2, 1, 0x20));
+HEX(INSERT(_utf8 0xD18FD18E, 2, 1, 0x20))
+D120D18E
+End of 5.1 tests

mysql-test/t/ctype_utf8.test

@@ -1466,3 +1466,23 @@ SELECT CONVERT(a, CHAR), CONVERT(b, CHAR) from t1 GROUP BY b;
 DROP TABLE t1;
 
 --echo End of 5.0 tests
+
+
+#
+# Bug #57272: crash in rpad() when using utf8
+#
+SELECT LENGTH(RPAD(0.0115E88, 61297, _utf8'яэюя'));
+SELECT LENGTH(RPAD(0.0115E88, 61297, _utf8'йцуя'));
+SELECT HEX(RPAD(0x20, 2, _utf8 0xD18F));
+SELECT HEX(RPAD(0x20, 4, _utf8 0xD18F));
+SELECT HEX(LPAD(0x20, 2, _utf8 0xD18F));
+SELECT HEX(LPAD(0x20, 4, _utf8 0xD18F));
+
+SELECT HEX(RPAD(_utf8 0xD18F, 3, 0x20));
+SELECT HEX(LPAD(_utf8 0xD18F, 3, 0x20));
+
+SELECT HEX(INSERT(_utf8 0xD18F, 2, 1, 0x20));
+SELECT HEX(INSERT(_utf8 0xD18FD18E, 2, 1, 0x20));
+
+
+--echo End of 5.1 tests

sql/item_strfunc.cc

@@ -1013,6 +1013,20 @@ String *Item_func_insert::val_str(String *str)
   if ((length < 0) || (length > res->length()))
     length= res->length();
 
+  /*
+    There is one exception not handled (intentionaly) by the character set
+    aggregation code. If one string is strong side and is binary, and
+    another one is weak side and is a multi-byte character string,
+    then we need to operate on the second string in terms on bytes when
+    calling ::numchars() and ::charpos(), rather than in terms of characters.
+    Lets substitute its character set to binary.
+  */
+  if (collation.collation == &my_charset_bin)
+  {
+    res->set_charset(&my_charset_bin);
+    res2->set_charset(&my_charset_bin);
+  }
+
   /* start and length are now sufficiently valid to pass to charpos function */
    start= res->charpos((int) start);
    length= res->charpos((int) length, (uint32) start);
@@ -2514,6 +2528,20 @@ String *Item_func_rpad::val_str(String *str)
   /* Set here so that rest of code sees out-of-bound value as such. */
   if ((ulonglong) count > INT_MAX32)
     count= INT_MAX32;
+  /*
+    There is one exception not handled (intentionaly) by the character set
+    aggregation code. If one string is strong side and is binary, and
+    another one is weak side and is a multi-byte character string,
+    then we need to operate on the second string in terms on bytes when
+    calling ::numchars() and ::charpos(), rather than in terms of characters.
+    Lets substitute its character set to binary.
+  */
+  if (collation.collation == &my_charset_bin)
+  {
+    res->set_charset(&my_charset_bin);
+    rpad->set_charset(&my_charset_bin);
+  }
+
   if (count <= (res_char_length= res->numchars()))
   {						// String to pad is big enough
     res->length(res->charpos((int) count));	// Shorten result if longer
@@ -2616,6 +2644,20 @@ String *Item_func_lpad::val_str(String *str)
   if ((ulonglong) count > INT_MAX32)
     count= INT_MAX32;
 
+  /*
+    There is one exception not handled (intentionaly) by the character set
+    aggregation code. If one string is strong side and is binary, and
+    another one is weak side and is a multi-byte character string,
+    then we need to operate on the second string in terms on bytes when
+    calling ::numchars() and ::charpos(), rather than in terms of characters.
+    Lets substitute its character set to binary.
+  */
+  if (collation.collation == &my_charset_bin)
+  {
+    res->set_charset(&my_charset_bin);
+    pad->set_charset(&my_charset_bin);
+  }
+
   res_char_length= res->numchars();
 
   if (count <= res_char_length)