rfc:taint
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rfc:taint [2008/07/06 23:04] – wietse | rfc:taint [2009/01/30 15:46] – wietse | ||
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====== Taint support for PHP ====== | ====== Taint support for PHP ====== | ||
- | * **Author:** Wietse Venema (wietse@porcupine.org) \\ IBM T.J. Watson Research Center \\ Hawthorne, NY, USA | + | * **Author: |
* **Version: | * **Version: | ||
* **Source code:** [[ftp:// | * **Source code:** [[ftp:// | ||
* **Win32 binaries:** [[ftp:// | * **Win32 binaries:** [[ftp:// | ||
+ | * **Mailing list: ** [[http:// | ||
* **Miscellaneous: | * **Miscellaneous: | ||
* **Status:** In the works | * **Status:** In the works | ||
- | | ||
===== Introduction ===== | ===== Introduction ===== | ||
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===== What has been implemented sofar ===== | ===== What has been implemented sofar ===== | ||
- | I have built taint support with the following server APIs: cli, cgi; apache1, apache2 and apache2filter plug-in; and with the the following extensions: mysqli, mysql and mbstring. Other server APIs and extensions will follow as time permits. | + | I have implemented |
What about the other extensions? The other extensions will work just fine as long as you leave " | What about the other extensions? The other extensions will work just fine as long as you leave " | ||
Extensions that haven' | Extensions that haven' | ||
+ | |||
===== Using taint support with real PHP applications ===== | ===== Using taint support with real PHP applications ===== | ||
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Taint support is implemented with some of the unused bits in the zval data structure. The zval is the PHP equivalent of a memory cell. Besides a type (string, integer, etc.) and value, each zval has a reference count and a flag that says whether the zval is a reference to yet another zval that contains the actual value. | Taint support is implemented with some of the unused bits in the zval data structure. The zval is the PHP equivalent of a memory cell. Besides a type (string, integer, etc.) and value, each zval has a reference count and a flag that says whether the zval is a reference to yet another zval that contains the actual value. | ||
- | Right now I am using eight bits, but there is room for more: 32-bit UNIX compilers such as GCC add 16 bits of padding to the current zval data structure, and this amount of padding isn't going to be smaller on 64-bit architectures; | + | Right now I am using eight bits, but there is room for more: 32-bit UNIX compilers such as GCC add 16 bits of padding to the current zval data structure, and this amount of padding isn't going to be smaller on 64-bit architectures; |
The preliminary configuration user interface is rather low-level, somewhat like MS-DOS file permissions :-( This is good enough for testing and debugging the taint support itself, but I would not want to have wires hanging out of the machine like this forever. The raw bits will need to be encapsulated so that applications can work with meaningful names and abstractions. | The preliminary configuration user interface is rather low-level, somewhat like MS-DOS file permissions :-( This is good enough for testing and debugging the taint support itself, but I would not want to have wires hanging out of the machine like this forever. The raw bits will need to be encapsulated so that applications can work with meaningful names and abstractions. |
rfc/taint.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1