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From: David Howells <dhowells@redhat.com>
To: Eric Biggers <ebiggers3@gmail.com>
Cc: dhowells@redhat.com, James Morris <jmorris@namei.org>,
	keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com, Tycho Andersen <tycho@tycho.ws>,
	Kees Cook <keescook@chromium.org>,
	Stephan Mueller <smueller@chronox.de>,
	Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH] dh key: fix rounding up KDF output length
Date: Fri, 08 Jun 2018 16:37:58 +0100	[thread overview]
Message-ID: <17595.1528472278@warthog.procyon.org.uk> (raw)
In-Reply-To: <20180607191201.97080-1-ebiggers3@gmail.com>

Eric Biggers <ebiggers3@gmail.com> wrote:

> Commit 383203eff718 ("dh key: get rid of stack allocated array") changed
> kdf_ctr() to assume that the length of key material to derive is a
> multiple of the digest size.  The length was supposed to be rounded up
> accordingly.  However, the round_up() macro was used which only gives
> the correct result on power-of-2 arguments, whereas not all hash
> algorithms have power-of-2 digest sizes.  In some cases this resulted in
> a write past the end of the 'outbuf' buffer.
> 
> Fix it by switching to roundup(), which works for non-power-of-2 inputs.

Applied.

  parent reply	other threads:[~2018-06-08 15:38 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07 13:07 KASAN: slab-out-of-bounds Write in sha1_finup syzbot
2018-06-07 14:43 ` syzbot
2018-06-07 19:12 ` [PATCH] dh key: fix rounding up KDF output length Eric Biggers
2018-06-07 19:16   ` Kees Cook
2018-06-07 19:28     ` James Morris
2018-06-07 19:28     ` Eric Biggers
2018-06-07 20:28   ` Tycho Andersen
2018-06-08 15:37 ` David Howells [this message]
2018-06-25 17:14   ` Eric Biggers

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