On 08/16/2013 01:47 AM, Alex Jia wrote:
This issue is introduced by commit 0fc8909, the virBitmapIsSet() needs caller to ensure 'b < bitmap->max_bit', but it's lost in the virBitmapParse() caller, this will cause crash of libvirtd, with the patch, libvirtd no crash and can get a expected error "Failed to parse nodeset".
--- The caller virBitmapGetBit() can make sure 'b < bitmap->max_bit', so don't need to worry about higher caller for the virBitmapGetBit(), but the virBitmapParse() is called by many XML parser function, not sure which one can crash libvirtd with read-only client then probably require a CVE, I haven't a good way to check them now and only manually check them one by one.
If you are worried that a bug might be a CVE, it is best to practice responsible disclosure, and NOT post the patch upstream, but instead post to libvirt-security@redhat.com. That way, the problem can be discussed without public disclosure, rather than calling attention to the fact and making it easier to design a 0-day exploit. But now that this is already publicly disclosed, we have to hurry up both the fix, and our analysis of whether it is exploitable. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org