From: Herbert Xu <herbert@gondor.apana.org.au>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Eric Biggers <ebiggers3@gmail.com>,
linux-crypto@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Andrew Lutomirski <luto@kernel.org>,
Stephan Mueller <smueller@chronox.de>
Subject: Re: Remaining crypto API regressions with CONFIG_VMAP_STACK
Date: Wed, 14 Dec 2016 12:56:14 +0800 [thread overview]
Message-ID: <20161214045614.GB9592@gondor.apana.org.au> (raw)
In-Reply-To: <CALCETrVz4B2rthaKPJAOpiHm1kCh-mD2C5kKti0q8iBQ0QEzuA@mail.gmail.com>
On Tue, Dec 13, 2016 at 09:06:31AM -0800, Andy Lutomirski wrote:
>
> > Having 0 as type and CRYPTO_ALG_ASYNC as mask in general means
> > that we're requesting a sync algorithm (i.e., ASYNC bit off).
> >
> > However, it is completely unnecessary for shash as they can never
> > be async. So this could be changed to just ("michael_mic", 0, 0).
>
> I'm confused by a bunch of this.
>
> 1. Is it really the case that crypto_alloc_xyz(..., CRYPTO_ALG_ASYNC)
> means to allocate a *synchronous* transform? That's not what I
> expected.
crypto_alloc_xyz(name, 0, CRYPTO_ALG_ASYNC) allocates a sync tfm
and crypto_alloc_xyz(name, CRYPTO_ALG_ASYNC, CRYPTO_ALG_ASYNC)
allocates an async tfm while crypto_alloc_xyz(name, 0, 0) does
not care whether the allocated tfm is sync or asnc.
> 2. What guarantees that an async request is never allocated on the
> stack? If it's just convention, could an assertion be added
> somewhere?
Sure we can add an assertion.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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prev parent reply other threads:[~2016-12-14 4:56 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-09 23:08 Eric Biggers
2016-12-10 5:25 ` Andy Lutomirski
2016-12-10 5:32 ` Herbert Xu
2016-12-10 6:03 ` [kernel-hardening] " Eric Biggers
2016-12-10 8:16 ` Herbert Xu
2016-12-10 8:39 ` Eric Biggers
2016-12-10 5:37 ` Herbert Xu
2016-12-10 6:30 ` [kernel-hardening] " Eric Biggers
2016-12-10 14:45 ` Jason A. Donenfeld
2016-12-10 17:48 ` Andy Lutomirski
2016-12-10 5:55 ` Eric Biggers
2016-12-11 19:13 ` Andy Lutomirski
2016-12-11 23:31 ` Eric Biggers
2016-12-12 18:34 ` Andy Lutomirski
2016-12-12 18:45 ` Gary R Hook
2016-12-13 3:39 ` Herbert Xu
2016-12-13 3:39 ` Herbert Xu
2016-12-13 17:06 ` Andy Lutomirski
2016-12-14 4:56 ` Herbert Xu [this message]
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