improve ASAN instrumentation: table->record[0]

instrument table->record[0], table->record[1] and share->default_values. One should not access record image beyond share->reclength, even if table->record[0] has some unused space after it (functions that work with records, might get a copy of the record as an argument, and that copy - not being record[0] - might not have this buffer space at the end). See b80fa40 and 444587d

Author: vuvova

sql/table.cc

@@ -1269,9 +1269,10 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
  extra_rec_buf_length= uint2korr(head+59);
  rec_buff_length= ALIGN_SIZE(share->reclength + 1 + extra_rec_buf_length);
  share->rec_buff_length= rec_buff_length;
- if (!(record= (uchar *) alloc_root(&share->mem_root,
- rec_buff_length)))
+ if (!(record= (uchar *) alloc_root(&share->mem_root, rec_buff_length)))
  goto err; /* purecov: inspected */
+ MEM_NOACCESS(record, rec_buff_length);
+ MEM_UNDEFINED(record, share->reclength);
  share->default_values= record;
  if (mysql_file_pread(file, record, (size_t) share->reclength,
  record_offset, MYF(MY_NABP)))
@@ -2430,6 +2431,7 @@ int open_table_from_share(THD *thd, TABLE_SHARE *share, const char *alias,
  if (!(record= (uchar*) alloc_root(&outparam->mem_root,
  share->rec_buff_length * records)))
  goto err; /* purecov: inspected */
+ MEM_NOACCESS(record, share->rec_buff_length * records);
 
  if (records == 0)
  {
@@ -2444,6 +2446,8 @@ int open_table_from_share(THD *thd, TABLE_SHARE *share, const char *alias,
  else
  outparam->record[1]= outparam->record[0]; // Safety
  }
+ MEM_UNDEFINED(outparam->record[0], share->reclength);
+ MEM_UNDEFINED(outparam->record[1], share->reclength);
 
  if (!(field_ptr = (Field **) alloc_root(&outparam->mem_root,
  (uint) ((share->fields+1)*

storage/heap/ha_heap.cc

@@ -100,7 +100,15 @@ const char **ha_heap::bas_ext() const
 
 int ha_heap::open(const char *name, int mode, uint test_if_locked)
 {
- set_if_bigger(table->s->reclength, sizeof (uchar*));
+ if (table->s->reclength < sizeof (char*))
+ {
+ MEM_UNDEFINED(table->s->default_values + table->s->reclength,
+ sizeof(char*) - table->s->reclength);
+ table->s->reclength= sizeof(char*);
+ MEM_UNDEFINED(table->record[0], table->s->reclength);
+ MEM_UNDEFINED(table->record[1], table->s->reclength);
+ }
+
  internal_table= test(test_if_locked & HA_OPEN_INTERNAL_TABLE);
  if (internal_table || (!(file= heap_open(name, mode)) && my_errno == ENOENT))
  {