Bug #20605441 : BUFFER OVERFLOW IN MYSQLSLAP

Description:- mysqlslap is a diagnostic utility designed to
emulate client load for a MySQL server and to report the
timing of each stage. This utility crashes when invalid
values are passed to the options 'num_int_cols_opt' or
'num_chars_cols_opt' or 'engine'.

Analysis:- mysqlslap uses "parse_option()" to parse the
values specified to the options 'num_int_cols_opt',
'num_chars_cols_opt' and 'engine'. These options takes
values separated by commas. In "parse_option()", the comma
separated values are separated and copied into a buffer
without checking the length of the string to be copied. The
size of the buffer is defined by a macro HUGE_STRING_LENGTH
whose value is 8196. So if the length of the any of the
comma separated value exceeds HUGE_STRING_LENGTH, will
result in a buffer overflow.

Fix:- A check is introduced in "parse_option()" to check
whether the size of the string to be copied is more than
HUGE_STRING_LENGTH. If it is more, an error, "Invalid value
specified for the option 'xxx'" is thrown.
Option length was incorrectly calculated for the last comma
separated value. So fixed that as well.

client/mysqlslap.c

 /*
-   Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -245,7 +245,7 @@ void print_conclusions_csv(conclusions *con);
 void generate_stats(conclusions *con, option_string *eng, stats *sptr);
 uint parse_comma(const char *string, uint **range);
 uint parse_delimiter(const char *script, statement **stmt, char delm);
-uint parse_option(const char *origin, option_string **stmt, char delm);
+int parse_option(const char *origin, option_string **stmt, char delm);
 static int drop_schema(MYSQL *mysql, const char *db);
 uint get_random_string(char *buf);
 static statement *build_table_string(void);
@@ -1227,7 +1227,13 @@ get_options(int *argc,char ***argv)
   if (num_int_cols_opt)
   {
     option_string *str;
-    parse_option(num_int_cols_opt, &str, ',');
+    if(parse_option(num_int_cols_opt, &str, ',') == -1)
+    {
+      fprintf(stderr, "Invalid value specified for the option "
+              "'number-int-cols'\n");
+      option_cleanup(str);
+      return 1;
+    }
     num_int_cols= atoi(str->string);
     if (str->option)
       num_int_cols_index= atoi(str->option);
@@ -1237,7 +1243,13 @@ get_options(int *argc,char ***argv)
   if (num_char_cols_opt)
   {
     option_string *str;
-    parse_option(num_char_cols_opt, &str, ',');
+    if(parse_option(num_char_cols_opt, &str, ',') == -1)
+    {
+      fprintf(stderr, "Invalid value specified for the option "
+              "'number-char-cols'\n");
+      option_cleanup(str);
+      return 1;
+    }
     num_char_cols= atoi(str->string);
     if (str->option)
       num_char_cols_index= atoi(str->option);
@@ -1473,7 +1485,13 @@ get_options(int *argc,char ***argv)
     printf("Parsing engines to use.\n");
 
   if (default_engine)
-    parse_option(default_engine, &engine_options, ',');
+  {
+    if(parse_option(default_engine, &engine_options, ',') == -1)
+    {
+      fprintf(stderr, "Invalid value specified for the option 'engine'\n");
+      return 1;
+    }
+  }
 
   if (tty_password)
     opt_password= get_tty_password(NullS);
@@ -1946,7 +1964,7 @@ pthread_handler_t run_task(void *p)
   DBUG_RETURN(0);
 }
 
-uint
+int
 parse_option(const char *origin, option_string **stmt, char delm)
 {
   char *retstr;
@@ -1966,6 +1984,13 @@ parse_option(const char *origin, option_string **stmt, char delm)
     char buffer[HUGE_STRING_LENGTH];
     char *buffer_ptr;
 
+    /*
+      Return an error if the length of the any of the comma seprated value
+      exceeds HUGE_STRING_LENGTH.
+    */
+    if ((size_t)(retstr - ptr) > HUGE_STRING_LENGTH)
+      return -1;
+
     count++;
     strncpy(buffer, ptr, (size_t)(retstr - ptr));
     if ((buffer_ptr= strchr(buffer, ':')))
@@ -1998,6 +2023,13 @@ parse_option(const char *origin, option_string **stmt, char delm)
   {
     char *origin_ptr;
 
+    /*
+      Return an error if the length of the any of the comma seprated value
+      exceeds HUGE_STRING_LENGTH.
+    */
+    if (strlen(ptr) > HUGE_STRING_LENGTH)
+      return -1;
+
     if ((origin_ptr= strchr(ptr, ':')))
     {
       char *option_ptr;
@@ -2008,13 +2040,13 @@ parse_option(const char *origin, option_string **stmt, char delm)
       option_ptr= (char *)ptr + 1 + tmp->length;
 
       /* Move past the : and the first string */
-      tmp->option_length= (size_t)((ptr + length) - option_ptr);
+      tmp->option_length= strlen(option_ptr);
       tmp->option= my_strndup(option_ptr, tmp->option_length,
                               MYF(MY_FAE));
     }
     else
     {
-      tmp->length= (size_t)((ptr + length) - ptr);
+      tmp->length= strlen(ptr);
       tmp->string= my_strndup(ptr, tmp->length, MYF(MY_FAE));
     }