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Re: [PATCH v3] powerpc: strstr optimization
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Carlos O'Donell <carlos at redhat dot com>
- Cc: Tulio Magno Quites Machado Filho <tuliom at linux dot vnet dot ibm dot com>, Steve Munroe <sjmunroe at us dot ibm dot com>, Florian Weimer <fweimer at redhat dot com>, Ondřej Bílka <neleai at seznam dot cz>, GNU C Library <libc-alpha at sourceware dot org>, Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>
- Date: Wed, 22 Jul 2015 19:33:09 +0000
- Subject: Re: [PATCH v3] powerpc: strstr optimization
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On Wed, 22 Jul 2015, Carlos O'Donell wrote:
> > If there's a quadratic worst case newly introduced for 2.22, I'd consider
> > that a security hole (denial of service) that needs to block the release
> > of 2.22 until it's fixed (possibly by removing the implementation in
> > question).
> We have had quadratic worse case in our string routines for years without
> it blocking a release. I agree that it is not the best case for a release
And I believe we established a consensus, when removing the SSE4
implementation (bug 12100), that such implementations are not suitable for
inclusion in glibc.
> to have such behaviour, but should it block this release?
As a denial-of-service regression (for any code that may use strstr on
untrusted inputs), yes.
Joseph S. Myers