Fix checksum calculation for opcache #4804
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dstogov
approved these changes
Oct 9, 2019
cmb69
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Oct 9, 2019
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Merged as e2a6bf4 Thanks. |
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https://bugs.php.net/bug.php?id=78654
The checksum can be incorrectly computed when a file to be cached contains non-ascii characters. When the opcache computes the checksum before it writes the file it chains together two calls to zend_adler32.
https://github.com/php/php-src/blob/PHP-7.2.24/ext/opcache/zend_file_cache.c#L870
When the bin file containing the opcache is loaded it computes the checksum with a single call to zend_adler32.
https://github.com/php/php-src/blob/PHP-7.2.24/ext/opcache/zend_file_cache.c#L1461
The zend_adler32 function uses signed chars instead of unsigned chars. As a result non-ascii characters can have negative values. This means the checksum is incorrectly computed and chained calls can result in different values than a single call to zend_adler32.
https://github.com/php/php-src/blob/PHP-7.2.24/ext/opcache/zend_accelerator_util_funcs.c#L738
Added two pieces of additional logging. The first is to show when the opcache is load from a file into to memory. The second is to show the expect and actual checksums when when a file does not fails the check.