Sophie: php-manual-ro-0:20051028-1 noarch

php-manual-ro-20051028-1.noarch.rpm

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>&#13;    The greatest weakness in many PHP programs is not inherent in the
    language itself, but merely an issue of code not being written with
    security in mind. For this reason, you should always take the time
    to consider the implications of a given piece of code, to ascertain
    the possible damage if an unexpected variable is submitted to it.
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>Exemplu 16-17. Dangerous Variable Usage</B
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><code><font color="#000000">
<font color="#0000BB">&lt;?php<br /></font><font color="#FF8000">// remove a file from the user's home directory... or maybe<br />// somebody else's?<br /></font><font color="#0000BB">unlink </font><font color="#007700">(</font><font color="#0000BB">$evil_var</font><font color="#007700">);<br /><br /></font><font color="#FF8000">// Write logging of their access... or maybe an /etc/passwd entry?<br /></font><font color="#0000BB">fwrite </font><font color="#007700">(</font><font color="#0000BB">$fp</font><font color="#007700">, </font><font color="#0000BB">$evil_var</font><font color="#007700">);<br /><br /></font><font color="#FF8000">// Execute something trivial.. or rm -rf *?<br /></font><font color="#0000BB">system </font><font color="#007700">(</font><font color="#0000BB">$evil_var</font><font color="#007700">);<br /></font><font color="#0000BB">exec </font><font color="#007700">(</font><font color="#0000BB">$evil_var</font><font color="#007700">);<br /><br /></font><font color="#0000BB">?&gt;</font>
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>
    You should always carefully examine your code to make sure that any
    variables being submitted from a web browser are being properly
    checked, and ask yourself the following questions:
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>&#13;       Will this script only affect the intended files?
      </P
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>&#13;       Can unusual or undesirable data be acted upon?
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>&#13;       Can this script be used in unintended ways?
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>&#13;       Can this be used in conjunction with other scripts in a negative
       manner?
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>&#13;       Will any transactions be adequately logged?
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>
    By adequately asking these questions while writing the script,
    rather than later, you prevent an unfortunate re-write when you
    need to increase your security. By starting out with this mindset,
    you won't guarantee the security of your system, but you can help
    improve it.
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>&#13;    You may also want to consider turning off register_globals,
    magic_quotes, or other convenience settings which may confuse
    you as to the validity, source, or value of a given variable.
    Working with PHP in error_reporting(E_ALL) mode can also help warn
    you about variables being used before they are checked or
    initialized (so you can prevent unusual data from being
    operated upon).
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