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Re: CVE Request: glibc getaddrinfo() stack overflow
From: Marcus Meissner <meissner () suse de>
Date: Fri, 5 Apr 2013 11:58:27 +0200

On Wed, Apr 03, 2013 at 01:10:21PM +0200, Marcus Meissner wrote:
Hi,

A customer reported a glibc crash, which turned out to be a stack overflow in
getaddrinfo().

getaddrinfo() uses:
      struct sort_result results[nresults];
with nresults controlled by the nameservice chain (DNS or /etc/hosts).

This will be visible mostly on threaded applications with smaller stacksizes,
or operating near out of stack.

Reproducer I tried:
      $ for i in `seq 1 10000000`; do echo "ff00::$i a1" >>/etc/hosts; done
      $ ulimit -s 1024
      $ telnet a1
      Segmentation fault
      (clean out /etc/hosts again )


I am not sure you can usually push this amount of addresses via DNS for all
setups.

Andreas is currently pushing the patch to glibc GIT.

Reference:
https://bugzilla.novell.com/show_bug.cgi?id=813121

Upstream GLIBC commit is:
http://sourceware.org/git/?p=glibc.git;a=commit;h=1cef1b19089528db11f221e938f60b9b048945d7

Ciao, Marcus


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