Bug#27510150: MYSQLDUMP FAILS FOR SPECIFIC --WHERE CLAUSES

Description: Mysqldump utility fails for specific clauses
used with the option, 'where'.

Analysis:- Method, "fix_identifier_with_newline()" that
prefixes all occurrences of newline char ('\n') in incoming
buffer does not verify the size of the buffer. The buffer in
which the incoming buffer is copied is limited to 2048 bytes
and the method does not try to allocate additional memory
for larger incoming buffers.

Fix:- Method, "fix_identifier_with_newline()" is modified
to fix this issue.

client/mysqldump.c

 /*
-   Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2018, 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
@@ -549,7 +549,8 @@ static int dump_tablespaces_for_databases(char** databases);
 static int dump_tablespaces(char* ts_where);
 static void print_comment(FILE *sql_file, my_bool is_error, const char *format,
                           ...);
-static const char* fix_identifier_with_newline(char*);
+static char const* fix_identifier_with_newline(char const* object_name,
+                                               my_bool* freemem);
 
 
 /*
@@ -644,13 +645,19 @@ static void write_header(FILE *sql_file, char *db_name)
   }
   else if (!opt_compact)
   {
+    my_bool freemem= FALSE;
+    char const* text= fix_identifier_with_newline(db_name, &freemem);
+
     print_comment(sql_file, 0,
                   "-- MySQL dump %s  Distrib %s, for %s (%s)\n--\n",
                   DUMP_VERSION, MYSQL_SERVER_VERSION, SYSTEM_TYPE,
                   MACHINE_TYPE);
     print_comment(sql_file, 0, "-- Host: %s    Database: %s\n",
                   current_host ? current_host : "localhost",
-                  db_name ? fix_identifier_with_newline(db_name) : "");
+                  text);
+    if (freemem)
+      my_free((void*)text);
+
     print_comment(sql_file, 0,
                   "-- ------------------------------------------------------\n"
                  );
@@ -1982,31 +1989,84 @@ static void print_comment(FILE *sql_file, my_bool is_error, const char *format,
   print_xml_comment(sql_file, strlen(comment_buff), comment_buff);
 }
 
-/*
- This function accepts object names and prefixes -- wherever \n
- character is found.
 
- @param[in]     object_name
+/**
+  @brief Accepts object names and prefixes them with "-- " wherever
+         end-of-line character ('\n') is found.
+
+  @param[in]  object_name   object name list (concatenated string)
+  @param[out] freemem       should buffer be released after usage
 
   @return
-    @retval fixed object name.
+    @retval                 pointer to a string with prefixed objects
 */
-
-static const char* fix_identifier_with_newline(char* object_name)
+static char const* fix_identifier_with_newline(char const* object_name, my_bool* freemem)
 {
-  static char buff[COMMENT_LENGTH]= {0};
-  char *ptr= buff;
-  memset(buff, 0, 255);
-  while(*object_name)
+  const size_t PREFIX_LENGTH= 3; // strlen ("-- ")
+
+  // static buffer for replacement procedure
+  static char storage[NAME_LEN + 1];
+  static char* buffer= storage;
+  static size_t buffer_size= sizeof(storage) - 1;
+  size_t index= 0;
+  size_t required_size= 0;
+
+  // we presume memory allocation won't be needed
+  *freemem= FALSE;
+
+  // traverse and reformat objects
+  while (object_name && *object_name)
   {
-    *ptr++ = *object_name;
+    ++required_size;
     if (*object_name == '\n')
-      ptr= strmov(ptr, "-- ");
-    object_name++;
+      required_size+= PREFIX_LENGTH;
+
+    // do we need dynamic (re)allocation
+    if (required_size > buffer_size)
+    {
+      // new alloc size increased in COMMENT_LENGTH multiple
+      buffer_size= COMMENT_LENGTH * (1 + required_size/COMMENT_LENGTH);
+
+      // is our buffer already dynamically allocated
+      if (*freemem)
+      {
+        // just realloc
+        buffer= (char*)my_realloc(buffer, buffer_size + 1, MYF(MY_WME));
+        if (!buffer)
+          exit(1);
       }
-  return buff;
+      else
+      {
+        // dynamic allocation + copy from static buffer
+        buffer= (char*)my_malloc(buffer_size + 1, MYF(MY_WME));
+        if (!buffer)
+          exit(1);
+
+        strncpy(buffer, storage, index);
+        *freemem= TRUE;
+      }
+    }
+
+    // copy a character
+    buffer[index]= *object_name;
+    ++index;
+
+    // prefix new lines with double dash
+    if (*object_name == '\n')
+    {
+      strcpy(buffer + index, "-- ");
+      index += PREFIX_LENGTH;
+    }
+
+    ++object_name;
+  }
+
+  // don't forget null termination
+  buffer[index]= '\0';
+  return buffer;
 }
 
+
 /*
  create_delimiter
  Generate a new (null-terminated) string that does not exist in  query 
@@ -2066,6 +2126,8 @@ static uint dump_events_for_db(char *db)
 
   char       db_cl_name[MY_CS_NAME_SIZE];
   int        db_cl_altered= FALSE;
+  my_bool    freemem= FALSE;
+  char const *text= fix_identifier_with_newline(db, &freemem);
 
   DBUG_ENTER("dump_events_for_db");
   DBUG_PRINT("enter", ("db: '%s'", db));
@@ -2075,7 +2137,9 @@ static uint dump_events_for_db(char *db)
   /* nice comments */
   print_comment(sql_file, 0,
                 "\n--\n-- Dumping events for database '%s'\n--\n",
-                fix_identifier_with_newline(db));
+                text);
+  if (freemem)
+    my_free((void*)text);
 
   /*
     not using "mysql_query_with_error_report" because we may have not
@@ -2284,6 +2348,8 @@ static uint dump_routines_for_db(char *db)
 
   char       db_cl_name[MY_CS_NAME_SIZE];
   int        db_cl_altered= FALSE;
+  my_bool    freemem= FALSE;
+  char const *text= fix_identifier_with_newline(db, &freemem);
 
   DBUG_ENTER("dump_routines_for_db");
   DBUG_PRINT("enter", ("db: '%s'", db));
@@ -2292,8 +2358,10 @@ static uint dump_routines_for_db(char *db)
 
   /* nice comments */
   print_comment(sql_file, 0,
-                "\n--\n-- Dumping routines for database '%s'\n--\n",
-                fix_identifier_with_newline(db));
+                "\n--\n-- Dumping routines for database '%s'\n--\n", text);
+
+  if (freemem)
+    my_free((void*)text);
 
   /*
     not using "mysql_query_with_error_report" because we may have not
@@ -2348,11 +2416,17 @@ static uint dump_routines_for_db(char *db)
                              row[2] ? strlen(row[2]) : 0));
           if (row[2] == NULL)
           {
+            my_bool freemem= FALSE;
+            char const* text= fix_identifier_with_newline(current_user, &freemem);
+
             print_comment(sql_file, 1, "\n-- insufficient privileges to %s\n",
                           query_buff);
             print_comment(sql_file, 1,
                           "-- does %s have permissions on mysql.proc?\n\n",
-                          fix_identifier_with_newline(current_user));
+                          text);
+            if (freemem)
+              my_free((void*)text);
+
             maybe_die(EX_MYSQLERR,"%s has insufficent privileges to %s!", current_user, query_buff);
           }
           else if (strlen(row[2]))
@@ -2547,6 +2621,8 @@ static uint get_table_structure(char *table, char *db, char *table_type,
       /* Make an sql-file, if path was given iow. option -T was given */
       char buff[20+FN_REFLEN];
       MYSQL_FIELD *field;
+      my_bool freemem= FALSE;
+      char const *text;
 
       my_snprintf(buff, sizeof(buff), "show create table %s", result_table);
 
@@ -2563,14 +2639,17 @@ static uint get_table_structure(char *table, char *db, char *table_type,
         write_header(sql_file, db);
       }
 
+      text= fix_identifier_with_newline(result_table, &freemem);
       if (strcmp (table_type, "VIEW") == 0)         /* view */
         print_comment(sql_file, 0,
                       "\n--\n-- Temporary table structure for view %s\n--\n\n",
-                      fix_identifier_with_newline(result_table));
+                      text);
       else
         print_comment(sql_file, 0,
-                      "\n--\n-- Table structure for table %s\n--\n\n",
-                      fix_identifier_with_newline(result_table));
+                      "\n--\n-- Table structure for table %s\n--\n\n", text);
+
+      if (freemem)
+        my_free((void*)text);
 
       if (opt_drop)
       {
@@ -2803,6 +2882,9 @@ static uint get_table_structure(char *table, char *db, char *table_type,
     /* Make an sql-file, if path was given iow. option -T was given */
     if (!opt_no_create_info)
     {
+      my_bool freemem= FALSE;
+      char const *text;
+
       if (path)
       {
         if (!(sql_file= open_sql_file_for_table(table, O_WRONLY)))
@@ -2810,9 +2892,13 @@ static uint get_table_structure(char *table, char *db, char *table_type,
         write_header(sql_file, db);
       }
 
+      text= fix_identifier_with_newline(result_table, &freemem);
       print_comment(sql_file, 0,
                     "\n--\n-- Table structure for table %s\n--\n\n",
-                    fix_identifier_with_newline(result_table));
+                    text);
+      if (freemem)
+        my_free((void*)text);
+
       if (opt_drop)
         fprintf(sql_file, "DROP TABLE IF EXISTS %s;\n", result_table);
       if (!opt_xml)
@@ -3515,25 +3601,34 @@ static void dump_table(char *table, char *db)
   }
   else
   {
-    print_comment(md_result_file, 0,
-                  "\n--\n-- Dumping data for table %s\n--\n",
-                  fix_identifier_with_newline(result_table));
+    my_bool freemem= FALSE;
+    char const* text= fix_identifier_with_newline(result_table, &freemem);
+    print_comment(md_result_file, 0, "\n--\n-- Dumping data for table %s\n--\n",
+                  text);
+    if (freemem)
+      my_free((void*)text);
 
     dynstr_append_checked(&query_string, "SELECT /*!40001 SQL_NO_CACHE */ * FROM ");
     dynstr_append_checked(&query_string, result_table);
 
     if (where)
     {
-      print_comment(md_result_file, 0, "-- WHERE:  %s\n",
-        fix_identifier_with_newline(where));
+      freemem= FALSE;
+      text= fix_identifier_with_newline(where, &freemem);
+      print_comment(md_result_file, 0, "-- WHERE:  %s\n", text);
+      if (freemem)
+        my_free((void*)text);
 
       dynstr_append_checked(&query_string, " WHERE ");
       dynstr_append_checked(&query_string, where);
     }
     if (order_by)
     {
-      print_comment(md_result_file, 0, "-- ORDER BY:  %s\n",
-        fix_identifier_with_newline(order_by));
+      freemem= FALSE;
+      text= fix_identifier_with_newline(order_by, &freemem);
+      print_comment(md_result_file, 0, "-- ORDER BY:  %s\n", text);
+      if (freemem)
+        my_free((void*)text);
 
       dynstr_append_checked(&query_string, " ORDER BY ");
       dynstr_append_checked(&query_string, order_by);
@@ -4302,10 +4397,13 @@ static int init_dumping(char *database, int init_func(char*))
       */
       char quoted_database_buf[NAME_LEN*2+3];
       char *qdatabase= quote_name(database,quoted_database_buf,opt_quoted);
+      my_bool freemem= FALSE;
+      char const* text= fix_identifier_with_newline(qdatabase, &freemem);
 
-      print_comment(md_result_file, 0,
-                    "\n--\n-- Current Database: %s\n--\n",
-                    fix_identifier_with_newline(qdatabase));
+      print_comment(md_result_file, 0, "\n--\n-- Current Database: %s\n--\n",
+                    text);
+      if (freemem)
+        my_free((void*)text);
 
       /* Call the view or table specific function */
       init_func(qdatabase);
@@ -5265,6 +5363,8 @@ static my_bool get_view_structure(char *table, char* db)
   char       table_buff2[NAME_LEN*2+3];
   char       query[QUERY_LENGTH];
   FILE       *sql_file= md_result_file;
+  my_bool    freemem= FALSE;
+  char const *text;
   DBUG_ENTER("get_view_structure");
 
   if (opt_no_create_info) /* Don't write table creation info */
@@ -5309,9 +5409,11 @@ static my_bool get_view_structure(char *table, char* db)
     write_header(sql_file, db);
   }
 
+  text= fix_identifier_with_newline(result_table, &freemem);
   print_comment(sql_file, 0,
-                "\n--\n-- Final view structure for view %s\n--\n\n",
-                fix_identifier_with_newline(result_table));
+                "\n--\n-- Final view structure for view %s\n--\n\n", text);
+  if (freemem)
+    my_free((void*)text);
 
   /* Table might not exist if this view was dumped with --tab. */
   fprintf(sql_file, "/*!50001 DROP TABLE IF EXISTS %s*/;\n", opt_quoted_table);