Bug #73928 [NEW]: __zend_realloc doesn't respect len=0
From: dev at pp3345 dot net
Operating system: Linux
PHP version: 7.1.0
Package: Reproducible crash
Bug Type: Bug
Bug description:__zend_realloc doesn't respect len=0
Description:
------------
According to man realloc, realloc() may return NULL if a valid pointer
and size=0 is passed, e. g. realloc(<ptr>, 0) is the same as
free(<ptr>). However, __zend_realloc always interprets NULL as OOM and
therefore bails out when trying to reallocate a pointer to size 0. For
example, mysqlnd sometimes calls erealloc(<ptr>, 0), which will crash
PHP when running with USE_ZEND_ALLOC=0.
From zend_alloc.c, lines 2834 - 2841:
ZEND_API void * __zend_realloc(void *p, size_t len)
{
p = realloc(p, len);
if (EXPECTED(p)) {
return p;
}
zend_out_of_memory();
}
It should probably be something like if (EXPECTED(p) || !len).
--
Edit bug report at https://bugs.php.net/bug.php?id=73928&edit=1
--
Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=73928&r=trysnapshot54
Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=73928&r=trysnapshot55
Try a snapshot (trunk): https://bugs.php.net/fix.php?id=73928&r=trysnapshottrunk
Fixed in SVN: https://bugs.php.net/fix.php?id=73928&r=fixed
Fixed in release: https://bugs.php.net/fix.php?id=73928&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=73928&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=73928&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=73928&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=73928&r=support
Expected behavior: https://bugs.php.net/fix.php?id=73928&r=notwrong
Not enough info: https://bugs.php.net/fix.php?id=73928&r=notenoughinfo
Submitted twice: https://bugs.php.net/fix.php?id=73928&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=73928&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=73928&r=php4
Daylight Savings: https://bugs.php.net/fix.php?id=73928&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=73928&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=73928&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=73928&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=73928&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=73928&r=mysqlcfg
Thread (4 messages)
- dev at pp3345 dot net