Re: Comment on Bug #30153: FATAL erealloc() error when using gzinflate()

Ramus, Thanks for the response. Unfortunately, I don't have any great ideas on how to patch this and for now have just stopped using gzinflate :-/ Is there a way to reopen bug 30153? That description of this issue is pretty good and, even if the bug is hard to fix, it should still be tracked somewhere.... Tim Rasmus Lerdorf wrote:

Tim Nufire wrote:

Reposting from php-general@lists.php.net to the internals@lists.php.net list because I'm told that's the right place for a discussion like this.... In tracking down a bug that I am seeing on a site I work on, I came across bug #30153 (http://bugs.php.net/bug.php?id=30153). I must say I am shocked that this bug was closed as 'bogus'.... Not only is this a bug, it is a security issue! How can gzinflate not be responsible for validating the content passed to it? Not doing so exposes PHP servers that use this function to serious denial of service attacks.... Let me illustrate this issue using Magpierss (http://magpierss.sourceforge.net) which uses gzinflate to support gziped RSS feeds. Because Magpierss gets the compressed content from a foreign server, it does not control its validity. The only way to see if it is valid is to try to decompress it... Since this will crash the script when the content is not valid, using gzinflate in this way will expose any RSS aggregator that uses Magpierss to denial of service attacks. Since no other means are provide to validate the gzip content, I am at a loss to suggest a workaround to the Magpierss authors... This is just one example. Any server which decompresses content that it gets from a foreign source will have this same issue. IMO, crashing a script is never the right way to indicate that an error has occurred. Without a fix, gzinflate should only be used when the content comes from a trusted source. If I am missing something here or if there is a workaround to this problem, please let me know.

I agree it is a problem, but the fix isn't easy since the zlib library doesn't provide any help here. We'd welcome an intelligent patch for this. -Rasmus