From: Eric Biggers <ebiggers3@gmail.com>
To: kernel-hardening@lists.openwall.com
Cc: Andy Lutomirski <luto@amacapital.net>,
linux-crypto@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Lutomirski <luto@kernel.org>,
Stephan Mueller <smueller@chronox.de>
Subject: Re: [kernel-hardening] Re: Remaining crypto API regressions with CONFIG_VMAP_STACK
Date: Fri, 9 Dec 2016 22:03:16 -0800 [thread overview]
Message-ID: <20161210060316.GC6846@zzz> (raw)
In-Reply-To: <20161210053208.GA27951@gondor.apana.org.au>
On Sat, Dec 10, 2016 at 01:32:08PM +0800, Herbert Xu wrote:
> On Fri, Dec 09, 2016 at 09:25:38PM -0800, Andy Lutomirski wrote:
> >
> > > The following crypto drivers initialize a scatterlist to point into an
> > > ablkcipher_request, which may have been allocated on the stack with
> > > SKCIPHER_REQUEST_ON_STACK():
> > >
> > > drivers/crypto/ccp/ccp-crypto-aes-xts.c:162
> > > drivers/crypto/ccp/ccp-crypto-aes.c:94
> >
> > These are real, and I wish I'd known about them sooner.
>
> Are you sure? Any instance of *_ON_STACK must only be used with
> sync algorithms and most drivers under drivers/crypto declare
> themselves as async.
>
Why exactly is that? Obviously, it wouldn't work if you returned from the stack
frame before the request completed, but does anything stop someone from using an
*_ON_STACK() request and then waiting for the request to complete before
returning from the stack frame?
Eric
WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers <ebiggers3@gmail.com>
To: kernel-hardening@lists.openwall.com
Cc: Andy Lutomirski <luto@amacapital.net>,
linux-crypto@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Lutomirski <luto@kernel.org>,
Stephan Mueller <smueller@chronox.de>
Subject: Re: [kernel-hardening] Re: Remaining crypto API regressions with CONFIG_VMAP_STACK
Date: Fri, 9 Dec 2016 22:03:16 -0800 [thread overview]
Message-ID: <20161210060316.GC6846@zzz> (raw)
In-Reply-To: <20161210053208.GA27951@gondor.apana.org.au>
On Sat, Dec 10, 2016 at 01:32:08PM +0800, Herbert Xu wrote:
> On Fri, Dec 09, 2016 at 09:25:38PM -0800, Andy Lutomirski wrote:
> >
> > > The following crypto drivers initialize a scatterlist to point into an
> > > ablkcipher_request, which may have been allocated on the stack with
> > > SKCIPHER_REQUEST_ON_STACK():
> > >
> > > drivers/crypto/ccp/ccp-crypto-aes-xts.c:162
> > > drivers/crypto/ccp/ccp-crypto-aes.c:94
> >
> > These are real, and I wish I'd known about them sooner.
>
> Are you sure? Any instance of *_ON_STACK must only be used with
> sync algorithms and most drivers under drivers/crypto declare
> themselves as async.
>
Why exactly is that? Obviously, it wouldn't work if you returned from the stack
frame before the request completed, but does anything stop someone from using an
*_ON_STACK() request and then waiting for the request to complete before
returning from the stack frame?
Eric
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next prev parent reply other threads:[~2016-12-10 6:03 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-09 23:08 [kernel-hardening] Remaining crypto API regressions with CONFIG_VMAP_STACK Eric Biggers
2016-12-09 23:08 ` Eric Biggers
2016-12-09 23:08 ` Eric Biggers
2016-12-10 5:25 ` [kernel-hardening] " Andy Lutomirski
2016-12-10 5:25 ` Andy Lutomirski
2016-12-10 5:25 ` Andy Lutomirski
2016-12-10 5:32 ` [kernel-hardening] " Herbert Xu
2016-12-10 5:32 ` Herbert Xu
2016-12-10 5:32 ` Herbert Xu
2016-12-10 6:03 ` Eric Biggers [this message]
2016-12-10 6:03 ` [kernel-hardening] " Eric Biggers
2016-12-10 8:16 ` Herbert Xu
2016-12-10 8:16 ` Herbert Xu
2016-12-10 8:39 ` Eric Biggers
2016-12-10 8:39 ` Eric Biggers
2016-12-10 8:39 ` Eric Biggers
2016-12-10 5:37 ` [kernel-hardening] " Herbert Xu
2016-12-10 5:37 ` Herbert Xu
2016-12-10 5:37 ` Herbert Xu
2016-12-10 6:30 ` [kernel-hardening] " Eric Biggers
2016-12-10 6:30 ` Eric Biggers
2016-12-10 14:45 ` Jason A. Donenfeld
2016-12-10 14:45 ` Jason A. Donenfeld
2016-12-10 17:48 ` Andy Lutomirski
2016-12-10 17:48 ` Andy Lutomirski
2016-12-10 5:55 ` Eric Biggers
2016-12-10 5:55 ` Eric Biggers
2016-12-10 5:55 ` Eric Biggers
2016-12-11 19:13 ` [kernel-hardening] " Andy Lutomirski
2016-12-11 19:13 ` Andy Lutomirski
2016-12-11 19:13 ` Andy Lutomirski
2016-12-11 23:31 ` [kernel-hardening] " Eric Biggers
2016-12-11 23:31 ` Eric Biggers
2016-12-11 23:31 ` Eric Biggers
2016-12-12 18:34 ` [kernel-hardening] " Andy Lutomirski
2016-12-12 18:34 ` Andy Lutomirski
2016-12-12 18:34 ` Andy Lutomirski
2016-12-12 18:45 ` [kernel-hardening] " Gary R Hook
2016-12-12 18:45 ` Gary R Hook
2016-12-12 18:45 ` Gary R Hook
2016-12-12 18:45 ` Gary R Hook
2016-12-13 3:39 ` [kernel-hardening] " Herbert Xu
2016-12-13 3:39 ` Herbert Xu
2016-12-13 3:39 ` Herbert Xu
2016-12-13 3:39 ` [kernel-hardening] " Herbert Xu
2016-12-13 3:39 ` Herbert Xu
2016-12-13 3:39 ` Herbert Xu
2016-12-13 17:06 ` [kernel-hardening] " Andy Lutomirski
2016-12-13 17:06 ` Andy Lutomirski
2016-12-13 17:06 ` Andy Lutomirski
2016-12-14 4:56 ` [kernel-hardening] " Herbert Xu
2016-12-14 4:56 ` Herbert Xu
2016-12-14 4:56 ` Herbert Xu
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