Description
digest_length = (zend_long) ceil((float) length / 2.0);
returnval = zend_string_alloc(length, 0);
zend_bin2hex(ZSTR_VAL(returnval), result, digest_length);
ZSTR_VAL(returnval)[length] = 0;
If length is odd, digest_length is just over half of length. zend_bin2hex writes two bytes for every input byte, so it writes 2 * digest_length, which can be greater than length.
Example:
length = 5digest_length = 3zend_bin2hex writes 6 bytes to returnval, which has been allocated to 5 bytes.
PHP Version
master branch
PHP 8.6.0-dev (cli) (built: Aug 19 2026 12:05:36) (NTS DEBUG)
Copyright © The PHP Group and Contributors
Zend Engine v4.6.0-dev, Copyright © Zend by Perforce
with Zend OPcache v8.6.0-dev, Copyright ©, by Zend by Perforce
Operating System
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Description
If length is odd,
digest_lengthis just over half oflength.zend_bin2hexwrites two bytes for every input byte, so it writes 2 *digest_length, which can be greater thanlength.Example:
length= 5digest_length= 3zend_bin2hexwrites 6 bytes to returnval, which has been allocated to 5 bytes.PHP Version
Operating System
No response