[patch 54/86] drm: limit to INT_MAX in create_blob ioctl

Andrew Morton
2019-12-05T00:52:39Z

From: Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: drm: limit to INT_MAX in create_blob ioctl

The hardened usercpy code is too paranoid ever since:

commit 6a30afa8c1fbde5f10f9c584c2992aa3c7f7a8fe
Author: Kees Cook <keescook@chromium.org>
Date: Wed Nov 6 16:07:01 2019 +1100

uaccess: disallow > INT_MAX copy sizes

Code itself should have been fine as-is.

Link: http://lkml.kernel.org/r/20191106164755.31478-1-daniel.vetter@ffwll.ch
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reported-by: syzbot+fb77e97ebf0612ee6914@syzkaller.appspotmail.com
Fixes: 6a30afa8c1fb ("uaccess: disallow > INT_MAX copy sizes")
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

drivers/gpu/drm/drm_property.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_property.c~drm-limit-to-int_max-in-create_blob-ioctl
+++ a/drivers/gpu/drm/drm_property.c
@@ -561,7 +561,7 @@ drm_property_create_blob(struct drm_devi
struct drm_property_blob *blob;
int ret;

- if (!length || length > ULONG_MAX - sizeof(struct drm_property_blob))
+ if (!length || length > INT_MAX - sizeof(struct drm_property_blob))
return ERR_PTR(-EINVAL);

blob = kvzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL);
_