linux-kernel - Re: Remaining crypto API regressions with CONFIG_VMAP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 13 Dec 2016 11:39:28 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Andy Lutomirski <luto@...capital.net>
Cc:     Eric Biggers <ebiggers3@...il.com>, linux-crypto@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "kernel-hardening@...ts.openwall.com" 
        <kernel-hardening@...ts.openwall.com>,
        Andrew Lutomirski <luto@...nel.org>,
        Stephan Mueller <smueller@...onox.de>
Subject: Re: Remaining crypto API regressions with CONFIG_VMAP_STACK

On Mon, Dec 12, 2016 at 10:34:10AM -0800, Andy Lutomirski wrote:
>
> Here's my status.
> 
> >         drivers/crypto/bfin_crc.c:351
> >         drivers/crypto/qce/sha.c:299
> >         drivers/crypto/sahara.c:973,988
> >         drivers/crypto/talitos.c:1910
> >         drivers/crypto/qce/sha.c:325
> 
> I have a patch to make these depend on !VMAP_STACK.

Why? They're all marked as ASYNC AFAIK.

> I have a patch to convert this to, drumroll please:
> 
>     priv->tx_tfm_mic = crypto_alloc_shash("michael_mic", 0,
>                           CRYPTO_ALG_ASYNC);
> 
> Herbert, I'm at a loss as what a "shash" that's "ASYNC" even means.

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).

> >         net/ceph/crypto.c:182
> 
> This:
> 
> size_t zero_padding = (0x10 - (src_len & 0x0f));
> 
> is an amazing line of code...
> 
> But this driver uses cbc and wants to do synchronous crypto, and I
> don't think that the crypto API supports real synchronous crypto using
> CBC, so I'm going to let someone else fix this.

It does through skcipher if you allocate with (0, CRYPTO_ALG_ASYNC).

I'll try to fix this.

> >         net/rxrpc/rxkad.c:737,1000
> 
> Herbert, can you fix this?

Sure I'll take a look.

Thanks,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt