#25856 [NEW]: Segfault when copying uninitialized variable into array sub-index

From: cluby at omniture dot com Operating system: Linux PHP version: 4CVS-2003-10-13 (stable) PHP Bug Type: Reproducible crash Bug description: Segfault when copying uninitialized variable into array sub-index Description: ------------ The following snippet will cause a segfault in the CGI binary 4.3.1 and up including the latest snapshot using the default configure. It seemed to work fine in 4.1.2. When testing with the latest snapshot no changes were made to php.ini: <? $data = array(); for ($i = 0;$i < 70000;$i++) { $data[$i][1] = $x; // $x is undefined } ?> It segfaults when $i = 65533. It seems to be tied to the fact that it is copying the value of an uninitialized variable into a sub-index of an array. If you change the copy line to this: $y = 'foo'; ... $data[$i][1] = $y; or this: $data[$i] = $x; It will not segfault. Reproduce code: --------------- <? $data = array(); for ($i = 0;$i < 70000;$i++) { $data[$i][1] = $x; // $x is undefined } ?> Expected result: ---------------- Not segfault. Possibly fill sub-index 1 with "undefines" or not modify the array at all because there is nothing to copy. Actual result: -------------- Segfault when $i = 65533 GDB backtrace on CGI binary and core file: #0 0x0810e2bd in zend_hash_index_find (ht=0x0, h=1, pData=0x0) at /usr/local/src/php4-STABLE-200310131730/Zend/zend_hash.c:962 #1 0x08117f61 in zend_fetch_dimension_address_inner (ht=0x910dbc4, op2=0x8191c78, Ts=0xbfffd3f0, type=1) at /usr/local/src/php4-STABLE-200310131730/Zend/zend_execute.c:665 #2 0x08112b41 in zend_fetch_dimension_address (result=0x8191c58, op1=0x815f024, op2=0x8191c78, Ts=0xbfffd3f0, type=1) at /usr/local/src/php4-STABLE-200310131730/Zend/zend_execute.c:787 #3 0x08116c01 in execute (op_array=0x818d7f4) at /usr/local/src/php4-STABLE-200310131730/Zend/zend_execute.c:1287 #4 0x0810a313 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /usr/local/src/php4-STABLE-200310131730/Zend/zend.c:885 #5 0x080e9097 in php_execute_script (primary_file=0xbffff9b0) at /usr/local/src/php4-STABLE-200310131730/main/main.c:1729 #6 0x081192da in main (argc=2, argv=0xbffffa34) at /usr/local/src/php4-STABLE-200310131730/sapi/cgi/cgi_main.c:1578 #7 0x420158d4 in __libc_start_main () from /lib/i686/libc.so.6 -- Edit bug report at http://bugs.php.net/?id=25856&edit=1 -- Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=25856&r=trysnapshot4 Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=25856&r=trysnapshot5 Fixed in CVS: http://bugs.php.net/fix.php?id=25856&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=25856&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=25856&r=needtrace Try newer version: http://bugs.php.net/fix.php?id=25856&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=25856&r=support Expected behavior: http://bugs.php.net/fix.php?id=25856&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=25856&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=25856&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=25856&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=25856&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=25856&r=dst IIS Stability: http://bugs.php.net/fix.php?id=25856&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=25856&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=25856&r=float