From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 29 Jun 2017 12:59:26 +0000 (+0100)
Subject: dma-buf/sw-sync: Prevent user overflow on timeline advance
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8f66d3aa1735bc95ae58d846a157357e8d41abb8;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

dma-buf/sw-sync: Prevent user overflow on timeline advance

The timeline is u32, which limits any single advance to INT_MAX so that
we can detect all fences that need signaling.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170629125930.821-3-chris@chris-wilson.co.uk
---

diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index 4d5d8c5e2534..0e676d08aa70 100644
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -345,6 +345,11 @@ static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
 	if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
 		return -EFAULT;
 
+	while (value > INT_MAX)  {
+		sync_timeline_signal(obj, INT_MAX);
+		value -= INT_MAX;
+	}
+
 	sync_timeline_signal(obj, value);
 
 	return 0;