Fixed #74021 - fetch_array returned broken data

[andrewnester]

Fix for https://bugs.php.net/bug.php?id=74021

Was caused by https://github.com/php/php-src/pull/2249/files

Don't need this fix because it was fixed here: 9eca4dc#diff-e80df9670f007a4420b36aa40edf34ff

[nikic]

I don't think the linked commit fixes the issue from #2249. It only concerns bit fields.

[andrewnester]

@nikic I've added bug73800.phpt to check that #2249 doesn't occur.

[nikic]

As suspected, when running the test for bug 73800 you added under valgrind, I get memory errors:

==26369== Invalid read of size 1
==26369==    at 0xABBE49: php_mysqlnd_rowp_read_text_protocol_aux (mysqlnd_wireprotocol.c:1703)
==26369==    by 0xABC57F: php_mysqlnd_rowp_read_text_protocol_zval (mysqlnd_wireprotocol.c:1787)
==26369==    by 0xAF0927: mysqlnd_mysqlnd_result_buffered_zval_fetch_row_pub (mysqlnd_result.c:1096)
==26369==    by 0xAF2146: mysqlnd_mysqlnd_res_fetch_row_pub (mysqlnd_result.c:1275)
==26369==    by 0xAF6BFD: mysqlnd_mysqlnd_res_fetch_into_pub (mysqlnd_result.c:1754)
==26369==    by 0x7C80A6: php_mysqli_fetch_into_hash_aux (mysqli.c:1220)
==26369==    by 0x7C843E: php_mysqli_fetch_into_hash (mysqli.c:1271)
==26369==    by 0x7D836B: zif_mysqli_fetch_array (mysqli_nonapi.c:350)
==26369==    by 0xC76D40: ZEND_DO_FCALL_SPEC_RETVAL_USED_HANDLER (zend_vm_execute.h:1079)
==26369==    by 0xC74825: execute_ex (zend_vm_execute.h:432)
==26369==    by 0xC74AC4: zend_execute (zend_vm_execute.h:474)
==26369==    by 0xC05E7A: zend_execute_scripts (zend.c:1544)
==26369==  Address 0x11d9d8dc is 0 bytes after a block of size 18,000,028 alloc'd
==26369==    at 0x4C2FD5F: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==26369==    by 0xBC29E5: __zend_realloc (zend_alloc.c:2836)
==26369==    by 0xBC1A1F: _erealloc (zend_alloc.c:2443)
==26369==    by 0xAA2A22: _mysqlnd_erealloc (mysqlnd_alloc.c:267)
==26369==    by 0xB10147: mysqlnd_mempool_resize_chunk (mysqlnd_block_alloc.c:94)
==26369==    by 0xAB9B4A: php_mysqlnd_read_row_ex (mysqlnd_wireprotocol.c:1511)
==26369==    by 0xABCCFD: php_mysqlnd_rowp_read (mysqlnd_wireprotocol.c:1826)
==26369==    by 0xAF26A4: mysqlnd_mysqlnd_res_store_result_fetch_data_pub (mysqlnd_result.c:1326)
==26369==    by 0xAF373F: mysqlnd_mysqlnd_res_store_result_pub (mysqlnd_result.c:1443)
==26369==    by 0xA98876: mysqlnd_mysqlnd_conn_data_store_result_pub (mysqlnd_connection.c:1965)
==26369==    by 0x7D98B1: zif_mysqli_query (mysqli_nonapi.c:617)
==26369==    by 0xC76D40: ZEND_DO_FCALL_SPEC_RETVAL_USED_HANDLER (zend_vm_execute.h:1079)

[nikic]

The problem with the original patch appears to be that the realloc case is not handled correctly -- we pretend like the extra byte is part of the data there.

[nikic]

Merged via 01c1afa with a different fix. Now leaving data_size alone and instead only adding the extra byte when performing the actual alloc/realloc.