From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0C50D1C84DF; Tue, 24 Jun 2025 08:43:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750754637; cv=none; b=fxNSuk8b4xixRh4JgtKsBF1BasOsjfAy+qj/POrrjaA9ks/jbhwoM/pT8hhKeikJKbOb2PjhdtO6raJA9oXN2bXw6Kf2IswtboRVExBP7eAgYyBdGWDMPh7Gu39qREXNOiCIfZKts5cBnwI3RY/7jbOdgnr6gEo1iqZhvEfkHKY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750754637; c=relaxed/simple; bh=L45NXoZ+NSjgNfFv1Uc2lmPuDY4v3Gli3c8yBbV7E7w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Bh/UQfgq51SPSYM+Yk+o84rGWZdwEI9mQPAHVZxRHdc5eClEN2go+tZF+SKb4Q5OAcF7Jfr6oiqeoAWZ+yCa6vUb0uAC1aGiBxpykWqO+hfJsbMKVnQ/zqUmrtvh7Il971A0y8rNp3KUu1Vq2+5d/eDHPf9PbYJgK5aiZbO1Z0c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=XHVl1BJw; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="XHVl1BJw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1750754636; x=1782290636; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=L45NXoZ+NSjgNfFv1Uc2lmPuDY4v3Gli3c8yBbV7E7w=; b=XHVl1BJwW5fEfgTbW2fjpBy7RTiwWYDE//WvYkQo7Ljhxv83Ib83MQs/ Ol98vf60KqIfIR5ZEKJs/iSSqN8Lahf7ZSoFYFb3oVCl20eljDtZdT7Fx ncNxKIrqNvANmDpklC1n07ATLhX+MqX7+Z94xVYwY+9LLaZBo4lCXl42w f04vQ3F7hU28rPOPz/TbaVuXlMI7elCaaiUr7iPtj7B8Es4g8XviAKkyC DQSZmjV070ah/N/dO4YlKMcZKwXWG4gpoTvOJsam2fCc9QE+dm8w784AW dadPDuy5p10IxZk1l5rhQFl6Soqwe6eKpBDhRMF9hjT3QK1LeoT2ZcgTL g==; X-CSE-ConnectionGUID: tldknDeiRs21TRzIeNvquA== X-CSE-MsgGUID: AF+S4X9aTN2CQrIyUCGxrA== X-IronPort-AV: E=McAfee;i="6800,10657,11473"; a="52214092" X-IronPort-AV: E=Sophos;i="6.16,261,1744095600"; d="scan'208";a="52214092" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2025 01:43:56 -0700 X-CSE-ConnectionGUID: 2vYRGkSnQs618htWM63nfA== X-CSE-MsgGUID: OmmttEKCRhOgi6grzXo9MA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,261,1744095600"; d="scan'208";a="152023769" Received: from kuha.fi.intel.com ([10.237.72.152]) by orviesa007.jf.intel.com with SMTP; 24 Jun 2025 01:43:52 -0700 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Tue, 24 Jun 2025 11:43:51 +0300 Date: Tue, 24 Jun 2025 11:43:50 +0300 From: Heikki Krogerus To: RD Babiera Cc: badhri@google.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v1] usb: typec: altmodes/displayport: do not index invalid pin_assignments Message-ID: References: <20250618224943.3263103-2-rdbabiera@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250618224943.3263103-2-rdbabiera@google.com> On Wed, Jun 18, 2025 at 10:49:42PM +0000, RD Babiera wrote: > A poorly implemented DisplayPort Alt Mode port partner can indicate > that its pin assignment capabilities are greater than the maximum > value, DP_PIN_ASSIGN_F. In this case, calls to pin_assignment_show > will cause a BRK exception due to an out of bounds array access. > > Prevent for loop in pin_assignment_show from accessing > invalid values in pin_assignments by adding DP_PIN_ASSIGN_MAX > value in typec_dp.h and using i < DP_PIN_ASSIGN_MAX as a loop > condition. > > Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode") > Cc: stable@vger.kernel.org > Signed-off-by: RD Babiera > Reviewed-by: Badhri Jagan Sridharan Reviewed-by: Heikki Krogerus > --- > drivers/usb/typec/altmodes/displayport.c | 2 +- > include/linux/usb/typec_dp.h | 1 + > 2 files changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c > index b09b58d7311d..773786129dfb 100644 > --- a/drivers/usb/typec/altmodes/displayport.c > +++ b/drivers/usb/typec/altmodes/displayport.c > @@ -677,7 +677,7 @@ static ssize_t pin_assignment_show(struct device *dev, > > assignments = get_current_pin_assignments(dp); > > - for (i = 0; assignments; assignments >>= 1, i++) { > + for (i = 0; assignments && i < DP_PIN_ASSIGN_MAX; assignments >>= 1, i++) { > if (assignments & 1) { > if (i == cur) > len += sprintf(buf + len, "[%s] ", > diff --git a/include/linux/usb/typec_dp.h b/include/linux/usb/typec_dp.h > index f2da264d9c14..acb0ad03bdac 100644 > --- a/include/linux/usb/typec_dp.h > +++ b/include/linux/usb/typec_dp.h > @@ -57,6 +57,7 @@ enum { > DP_PIN_ASSIGN_D, > DP_PIN_ASSIGN_E, > DP_PIN_ASSIGN_F, /* Not supported after v1.0b */ > + DP_PIN_ASSIGN_MAX, > }; > > /* DisplayPort alt mode specific commands */ > > base-commit: e04c78d86a9699d136910cfc0bdcf01087e3267e > -- > 2.50.0.rc2.701.gf1e915cc24-goog -- heikki