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From:   Arnd Bergmann <arnd@arndb.de>
To:     y2038@lists.linaro.org, linux-kernel@vger.kernel.org,
        Lucas Stach <l.stach@pengutronix.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Russell King <linux+etnaviv@armlinux.org.uk>,
        Christian Gmeiner <christian.gmeiner@gmail.com>,
        =?UTF-8?q?Guido=20G=C3=BCnther?= <agx@sigxcpu.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Emil Velikov <emil.velikov@collabora.com>,
        Sam Ravnborg <sam@ravnborg.org>, etnaviv@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org
Subject: [PATCH v2 13/24] drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC
Date:   Fri, 13 Dec 2019 21:53:41 +0100
Message-Id: <20191213205417.3871055-4-arnd@arndb.de>
In-Reply-To: <20191213204936.3643476-1-arnd@arndb.de>
References: <20191213204936.3643476-1-arnd@arndb.de>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Most kernel interfaces that take a timespec require normalized
representation with tv_nsec between 0 and NSEC_PER_SEC.

Passing values larger than 0x100000000ull further behaves differently
on 32-bit and 64-bit kernels, and can cause the latter to spend a long
time counting seconds in timespec64_sub()/set_normalized_timespec64().

Reject those large values at the user interface to enforce sane and
portable behavior.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/etnaviv/etnaviv_drv.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
index 1f9c01be40d7..95d72dc00280 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
@@ -297,6 +297,9 @@ static int etnaviv_ioctl_gem_cpu_prep(struct drm_device *dev, void *data,
 	if (args->op & ~(ETNA_PREP_READ | ETNA_PREP_WRITE | ETNA_PREP_NOSYNC))
 		return -EINVAL;
 
+	if (args->timeout.tv_nsec > NSEC_PER_SEC)
+		return -EINVAL;
+
 	obj = drm_gem_object_lookup(file, args->handle);
 	if (!obj)
 		return -ENOENT;
@@ -360,6 +363,9 @@ static int etnaviv_ioctl_wait_fence(struct drm_device *dev, void *data,
 	if (args->flags & ~(ETNA_WAIT_NONBLOCK))
 		return -EINVAL;
 
+	if (args->timeout.tv_nsec > NSEC_PER_SEC)
+		return -EINVAL;
+
 	if (args->pipe >= ETNA_MAX_PIPES)
 		return -EINVAL;
 
@@ -411,6 +417,9 @@ static int etnaviv_ioctl_gem_wait(struct drm_device *dev, void *data,
 	if (args->flags & ~(ETNA_WAIT_NONBLOCK))
 		return -EINVAL;
 
+	if (args->timeout.tv_nsec > NSEC_PER_SEC)
+		return -EINVAL;
+
 	if (args->pipe >= ETNA_MAX_PIPES)
 		return -EINVAL;
 
-- 
2.20.0