linux-kernel - [PATCH v3] drm/mgag200: Apply upper limit for clock variable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241115141449.709-1-m.masimov@maxima.ru>
Date: Fri, 15 Nov 2024 17:14:47 +0300
From: Murad Masimov <m.masimov@...ima.ru>
To: Dave Airlie <airlied@...hat.com>
CC: Murad Masimov <m.masimov@...ima.ru>, Thomas Zimmermann
	<tzimmermann@...e.de>, Jocelyn Falempe <jfalempe@...hat.com>, Maarten
 Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
	<mripard@...nel.org>, David Airlie <airlied@...il.com>, Simona Vetter
	<simona@...ll.ch>, Mathieu Larouche <mathieu.larouche@...rox.com>,
	<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
	<lvc-project@...uxtesting.org>
Subject: [PATCH v3] drm/mgag200: Apply upper limit for clock variable

If the value of the clock variable is higher than 800000, the value of the
variable m, which is used as a divisor, will remain zero, because
(clock * testp) will be higher than vcomax in every loop iteration, which
leads to skipping every iteration and leaving variable m unmodified.

Return -EINVAL just after the loop, if m is still 0.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: e829d7ef9f17 ("drm/mgag200: Add support for a new rev of G200e")
Signed-off-by: Murad Masimov <m.masimov@...ima.ru>
---
 drivers/gpu/drm/mgag200/mgag200_g200se.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/mgag200/mgag200_g200se.c b/drivers/gpu/drm/mgag200/mgag200_g200se.c
index 7a32d3b1d226..4d65ead63d66 100644
--- a/drivers/gpu/drm/mgag200/mgag200_g200se.c
+++ b/drivers/gpu/drm/mgag200/mgag200_g200se.c
@@ -249,6 +249,9 @@ static int mgag200_g200se_04_pixpllc_atomic_check(struct drm_crtc *crtc,
 		}
 	}

+	if (m == 0)
+		return -EINVAL;
+
 	fvv = pllreffreq * n / m;
 	fvv = (fvv - 800000) / 50000;
 	if (fvv > 15)
--
2.39.2