From: Kees Cook <keescook@chromium.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: linux-fbdev@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
Jiri Slaby <jslaby@suse.com>,
syzbot <syzbot+017265e8553724e514e8@syzkaller.appspotmail.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH v3] vt: Reject zero-sized screen buffer size.
Date: Wed, 19 Aug 2020 15:07:46 -0700 [thread overview]
Message-ID: <202008191452.0278B57D43@keescook> (raw)
In-Reply-To: <20200712111013.11881-1-penguin-kernel@I-love.SAKURA.ne.jp>
On Sun, Jul 12, 2020 at 08:10:12PM +0900, Tetsuo Handa wrote:
> [...]
> @@ -1125,6 +1134,11 @@ int vc_allocate(unsigned int currcons) /* return 0 on success */
> if (!*vc->vc_uni_pagedir_loc)
> con_set_default_unimap(vc);
>
> + err = -EINVAL;
> + if (vc->vc_cols > VC_MAXCOL || vc->vc_rows > VC_MAXROW ||
> + vc->vc_screenbuf_size > KMALLOC_MAX_SIZE || !vc->vc_screenbuf_size)
> + goto err_free;
> + err = -ENOMEM;
> vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
> if (!vc->vc_screenbuf)
> goto err_free;
I realize this patch already landed, but I wanted to remind folks to
use the check_*_overflow() helpers, which can make a lot of this kind
of stuff easier to deal with.
For example, in this case, I think visual_init() could likely be changed
to return success/failure and do all the sanity checking:
if (check_shl_overflow(vc->vc_cols, 1, &vc->vc_size_row) ||
check_mul_overflow(vc->vc_rows, vc->vc_size_row, &vc->vc_screenbuf_size))
return -EINVAL;
--
Kees Cook
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prev parent reply other threads:[~2020-08-19 22:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200710055329.3759-1-penguin-kernel@I-love.SAKURA.ne.jp>
2020-07-10 5:56 ` fbconsole needs more parameter validations Tetsuo Handa
2020-07-10 10:56 ` Greg Kroah-Hartman
2020-07-11 6:16 ` Tetsuo Handa
2020-07-11 11:08 ` Tetsuo Handa
2020-07-12 11:10 ` [PATCH v3] vt: Reject zero-sized screen buffer size Tetsuo Handa
2020-07-12 11:10 ` [PATCH] fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins Tetsuo Handa
[not found] ` <CGME20200714072231eucas1p17c53f0a661346ebfd316ebd5796ca346@eucas1p1.samsung.com>
2020-07-14 7:22 ` Bartlomiej Zolnierkiewicz
2020-07-14 10:27 ` Tetsuo Handa
2020-07-14 13:37 ` Tetsuo Handa
2020-07-15 1:51 ` [PATCH v2] " Tetsuo Handa
2020-07-15 9:48 ` Dan Carpenter
2020-07-15 11:17 ` Tetsuo Handa
2020-07-15 14:02 ` Tetsuo Handa
2020-07-15 15:12 ` Dan Carpenter
2020-07-15 15:29 ` Tetsuo Handa
2020-07-16 10:00 ` Daniel Vetter
2020-07-16 11:27 ` Tetsuo Handa
2020-07-21 16:08 ` Greg Kroah-Hartman
2020-07-22 8:07 ` Daniel Vetter
2020-07-23 14:21 ` Greg Kroah-Hartman
2020-07-24 8:28 ` Bartlomiej Zolnierkiewicz
2020-07-14 17:15 ` [PATCH] " George Kennedy
2020-07-15 0:24 ` Tetsuo Handa
2020-08-19 22:07 ` Kees Cook [this message]
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