Messages in this thread | | | From | Stephan Mueller <> | Subject | Re: [PATCH v2] crypto: AF_ALG - limit mask and type | Date | Fri, 22 Dec 2017 08:41:10 +0100 |
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Am Freitag, 22. Dezember 2017, 08:36:07 CET schrieb Herbert Xu:
Hi Herbert,
> On Tue, Dec 19, 2017 at 07:25:04AM +0100, Stephan Müller wrote: > > The user space interface allows specifying the type and the mask field > > used to allocate the cipher. As user space can precisely select the > > desired cipher by using either the name or the driver name, additional > > selection options for cipher are not considered necessary and relevant > > for user space. > > > > This fixes a bug where user space is able to cause one cipher to be > > registered multiple times potentially exhausting kernel memory. > > > > Reported-by: syzbot <syzkaller@googlegroups.com> > > Cc: <stable@vger.kernel.org> > > Signed-off-by: Stephan Mueller <smueller@chronox.de> > > This will break users of CRYPTO_ALG_KERN_DRIVER_ONLY. I think > we should add CRYPTO_ALG_TESTED to the blacklist since there is > no sane reason to use it here.
Shouldn't we then rather use a white list instead of a black list? > > Most other problems however would be bugs in the template code. > The first thing a template does when it creates an instance is > to check whether the resulting algorithm would fulfil the requested > type/mask using crypto_check_attr_type. So if that's not working > then we should fix it there as it may also be triggered via other > code paths that can create instances.
I think I understand that, but does user space need to utilize this logic? > > Thanks,
Ciao Stephan
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