From 69ef943dbc14b21987c79f8399ffea08f9a1b446 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Thu, 14 Feb 2019 11:03:48 -0800 Subject: [PATCH] drm: Use array_size() when creating lease Passing an object_count of sufficient size will make object_count * 4 wrap around to be very small, then a later function will happily iterate off the end of the object_ids array. Using array_size() will saturate at SIZE_MAX, the kmalloc() will fail and we'll return an -ENOMEM to the norty userspace. Fixes: 62884cd386b8 ("drm: Add four ioctls for managing drm mode object leases [v7]") Signed-off-by: Matthew Wilcox Acked-by: Kees Cook Acked-by: Daniel Vetter Cc: # v4.15+ Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_lease.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c index 99cba8e..5df1256 100644 --- a/drivers/gpu/drm/drm_lease.c +++ b/drivers/gpu/drm/drm_lease.c @@ -528,7 +528,8 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, object_count = cl->object_count; - object_ids = memdup_user(u64_to_user_ptr(cl->object_ids), object_count * sizeof(__u32)); + object_ids = memdup_user(u64_to_user_ptr(cl->object_ids), + array_size(object_count, sizeof(__u32))); if (IS_ERR(object_ids)) return PTR_ERR(object_ids); -- 2.7.4