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

commit 8f66d3aa1735bc95ae58d846a157357e8d41abb8 upstream.

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
[s/dma_fence/fence/g - gregkh]
Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index 77ede2a..1098af2 100644 (file)
--- 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;