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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>,
	linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
	Ran Menscher <ran.menscher@karambasecurity.com>
Subject: Re: [PATCH 2/2] Bluetooth: check the buffer size for some messages before parsing
Date: Fri, 18 Jan 2019 11:21:23 +0100	[thread overview]
Message-ID: <20190118102123.GB20179@kroah.com> (raw)
In-Reply-To: <39E6B251-4ED3-4C0F-B8A2-0FAAF6E905A6@holtmann.org>

On Fri, Jan 18, 2019 at 10:37:25AM +0100, Marcel Holtmann wrote:
> Hi Greg,
> 
> > The L2CAP_CONF_EFS and L2CAP_CONF_RFC messages can be sent from
> > userspace so their structure sizes need to be checked before parsing
> > them.
> 
> this message is confusing me. How can these be send from userspace?

So claimed the original reporter.  You have the information in your
inbox, is it incorrect?

> > 
> > Based on a patch from Ran Menscher.
> > 
> > Reported-by: Ran Menscher <ran.menscher@karambasecurity.com>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> > net/bluetooth/l2cap_core.c | 12 ++++++++----
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> > 
> > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> > index 93daf94565cf..55e48e6efc2b 100644
> > --- a/net/bluetooth/l2cap_core.c
> > +++ b/net/bluetooth/l2cap_core.c
> > @@ -3361,7 +3361,8 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data
> > 			break;
> > 
> > 		case L2CAP_CONF_RFC:
> > -			if (olen == sizeof(rfc))
> > +			if ((olen == sizeof(rfc)) &&
> > +			    (endptr - ptr >= L2CAP_CONF_OPT_SIZE + sizeof(rfc)))
> > 				memcpy(&rfc, (void *) val, olen);
> 
> We don’t do ((x == y) && (..)) actually. Using (x == y && ..) is plenty.

Ick, ok, whatever, you all trust that your brains can remember C
priority levels, me, I trust ()...

I can fix this up to remove the extra (), but I would like _SOMEONE_ to
at least validate that this resolves the reported issues...

thanks,

greg k-h

  reply	other threads:[~2019-01-18 10:21 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-10  6:28 [PATCH 1/2] Bluetooth: check message types in l2cap_get_conf_opt Greg Kroah-Hartman
2019-01-10  6:29 ` [PATCH 2/2] Bluetooth: check the buffer size for some messages before parsing Greg Kroah-Hartman
2019-01-10  6:30   ` Greg Kroah-Hartman
2019-01-18  9:37   ` Marcel Holtmann
2019-01-18 10:21     ` Greg Kroah-Hartman [this message]
2019-01-18 11:11       ` Marcel Holtmann
2019-01-18 12:44         ` Marcel Holtmann
2019-01-10 21:02 ` [PATCH 1/2] Bluetooth: check message types in l2cap_get_conf_opt Joe Perches
2019-01-11  5:32   ` Greg Kroah-Hartman
2019-01-18  9:35 ` Marcel Holtmann
2019-01-18 10:19   ` Greg Kroah-Hartman
2019-01-18 11:09     ` Marcel Holtmann
2019-01-18 12:08       ` Marcel Holtmann

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