From: Dan Carpenter <dan.carpenter@oracle.com>
To: Denis Efremov <denis.e.efremov@oracle.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Stephen Kitt <steve@sk2.org>,
linux-input@vger.kernel.org, kernel-janitors@vger.kernel.org,
Alexander Larkin <avlarkin82@gmail.com>
Subject: Re: [PATCH] Input: joydev - prevent potential read overflow in ioctl
Date: Sat, 3 Jul 2021 15:43:51 +0300 [thread overview]
Message-ID: <20210703124351.GA26651@kadam> (raw)
In-Reply-To: <1c351258-65e8-8984-8ffa-64eb316e1573@oracle.com>
On Sat, Jul 03, 2021 at 02:20:13PM +0300, Denis Efremov wrote:
> Hi,
>
> CVE-2021-3612 was assigned to this patch.
>
>
> On 2/17/21 9:10 AM, Dan Carpenter wrote:
> > The problem here is that "len" might be less than "joydev->nabs" so the
> > loops which verfy abspam[i] and keypam[] might read beyond the buffer.
>
>
> The added check looks insufficient to me. There are second loops in these
> functions with unpatched "i < joydev->nabs;" and "i < joydev->nkey;" checks.
>
Thanks, Denis.
You're right. The fix isn't complete. We discussed this in a different
thread but I sort of assumed it was dealt with and didn't follow up. :/
https://lore.kernel.org/lkml/20210620120030.1513655-1-avlarkin82@gmail.com/
regards,
dan carpenter
> >
> > Fixes: 999b874f4aa3 ("Input: joydev - validate axis/button maps before clobbering current ones")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > drivers/input/joydev.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/input/joydev.c b/drivers/input/joydev.c
> > index a2b5fbba2d3b..750f4513fe20 100644
> > --- a/drivers/input/joydev.c
> > +++ b/drivers/input/joydev.c
> > @@ -456,7 +456,7 @@ static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
> > if (IS_ERR(abspam))
> > return PTR_ERR(abspam);
> >
> > - for (i = 0; i < joydev->nabs; i++) {
> > + for (i = 0; i < len && i < joydev->nabs; i++) {
> > if (abspam[i] > ABS_MAX) {
> > retval = -EINVAL;
> > goto out;
>
> memcpy(joydev->abspam, abspam, len);
>
> for (i = 0; i < joydev->nabs; i++) // <== HERE
> joydev->absmap[joydev->abspam[i]] = i;
>
>
> > @@ -487,7 +487,7 @@ static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
> > if (IS_ERR(keypam))
> > return PTR_ERR(keypam);
> >
> > - for (i = 0; i < joydev->nkey; i++) {
> > + for (i = 0; i < (len / 2) && i < joydev->nkey; i++) {
> > if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) {
> > retval = -EINVAL;
> > goto out;
> >
>
> memcpy(joydev->keypam, keypam, len);
>
> for (i = 0; i < joydev->nkey; i++) // <== HERE
> joydev->keymap[keypam[i] - BTN_MISC] = i;
>
>
> Also at the beginning of joydev_handle_JSIOCSAXMAP() there is a
> len = min(len, sizeof(joydev->abspam));
> abspam = memdup_user(argp, len);
>
> Maybe we can call min(len, joydev->nabs) instead or even min3() and
> use only len in the for loops then? Same for joydev_handle_JSIOCSBTNMAP.
>
> Thanks,
> Denis
next prev parent reply other threads:[~2021-07-03 12:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 6:10 [PATCH] Input: joydev - prevent potential read overflow in ioctl Dan Carpenter
2021-02-19 3:17 ` Dmitry Torokhov
2021-02-19 8:32 ` Dan Carpenter
2021-02-19 18:54 ` Dmitry Torokhov
2021-07-03 11:20 ` Denis Efremov
2021-07-03 12:43 ` Dan Carpenter [this message]
2021-07-03 14:34 ` Denis Efremov
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=20210703124351.GA26651@kadam \
--to=dan.carpenter@oracle.com \
--cc=avlarkin82@gmail.com \
--cc=denis.e.efremov@oracle.com \
--cc=dmitry.torokhov@gmail.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-input@vger.kernel.org \
--cc=steve@sk2.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).