[PATCH] drm/rockchip: fix wrong pitch/size using on gem

From: Mark Yao
Date: Wed Jan 20 2016 - 20:18:33 EST


args->pitch and args->size may not be set by userspace, sometimes
userspace only malloc args and not memset args to zero, then
args->pitch and args->size is random, it is very danger to use
pitch/size on gem.

pitch's type is u32, and min_pitch's type is int, example,
pitch is 0xffffffff, then pitch < min_pitch return true, then gem will
alloc very very big bufffer, it would eat all the memory and cause kernel
crash.

Stop using pitch/size from args, calc them from other args.

Signed-off-by: Mark Yao <mark.yao@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index d908321..18e0733 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -234,13 +234,8 @@ int rockchip_gem_dumb_create(struct drm_file *file_priv,
/*
* align to 64 bytes since Mali requires it.
*/
- min_pitch = ALIGN(min_pitch, 64);
-
- if (args->pitch < min_pitch)
- args->pitch = min_pitch;
-
- if (args->size < args->pitch * args->height)
- args->size = args->pitch * args->height;
+ args->pitch = ALIGN(min_pitch, 64);
+ args->size = args->pitch * args->height;

rk_obj = rockchip_gem_create_with_handle(file_priv, dev, args->size,
&args->handle);
--
1.7.9.5