From b5dcec693f87cb8475f2291c0075b2422addd3d6 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Tue, 19 Apr 2016 09:07:50 -0400 Subject: [PATCH] drm/radeon: forbid mapping of userptr bo through radeon device file MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Allowing userptr bo which are basicly a list of page from some vma (so either anonymous page or file backed page) would lead to serious corruption of kernel structures and counters (because we overwrite the page->mapping field when mapping buffer). This will already block if the buffer was populated before anyone does try to mmap it because then TTM_PAGE_FLAG_SG would be set in in the ttm_tt flags. But that flag is check before ttm_tt_populate in the ttm vm fault handler. So to be safe just add a check to verify_access() callback. Reviewed-by: Christian König Signed-off-by: Jérôme Glisse Cc: Signed-off-by: Alex Deucher --- drivers/gpu/drm/radeon/radeon_ttm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c index 7dddfdce85e6..90f739478a1b 100644 --- a/drivers/gpu/drm/radeon/radeon_ttm.c +++ b/drivers/gpu/drm/radeon/radeon_ttm.c @@ -235,6 +235,8 @@ static int radeon_verify_access(struct ttm_buffer_object *bo, struct file *filp) { struct radeon_bo *rbo = container_of(bo, struct radeon_bo, tbo); + if (radeon_ttm_tt_has_userptr(bo->ttm)) + return -EPERM; return drm_vma_node_verify_access(&rbo->gem_base.vma_node, filp); } -- 2.20.1