LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Tycho Andersen <tycho@tycho.ws>
To: Eric Biggers <ebiggers3@gmail.com>
Cc: David Howells <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,
	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: Thu, 7 Jun 2018 14:28:31 -0600	[thread overview]
Message-ID: <20180607202831.GG9999@cisco> (raw)
In-Reply-To: <20180607191201.97080-1-ebiggers3@gmail.com>

On Thu, Jun 07, 2018 at 12:12:01PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> 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.
> 
> Reported-by: syzbot+486f97f892efeb2075a3@syzkaller.appspotmail.com
> Reported-by: syzbot+29d17b7898b41ee120a5@syzkaller.appspotmail.com
> Reported-by: syzbot+8a608baf8751184ec727@syzkaller.appspotmail.com
> Reported-by: syzbot+d04e58bd384f1fe0b112@syzkaller.appspotmail.com
> Fixes: 383203eff718 ("dh key: get rid of stack allocated array")
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Arg, thanks.

Acked-by: Tycho Andersen <tycho@tycho.ws>

  parent reply	other threads:[~2018-06-07 20:28 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 [this message]
2018-06-08 15:37 ` David Howells
2018-06-25 17:14   ` Eric Biggers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180607202831.GG9999@cisco \
    --to=tycho@tycho.ws \
    --cc=dhowells@redhat.com \
    --cc=ebiggers3@gmail.com \
    --cc=ebiggers@google.com \
    --cc=jmorris@namei.org \
    --cc=keescook@chromium.org \
    --cc=keyrings@vger.kernel.org \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=smueller@chronox.de \
    --cc=syzkaller-bugs@googlegroups.com \
    --subject='Re: [PATCH] dh key: fix rounding up KDF output length' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).