alistair23-linux/drivers/gpu/drm/i915/i915_query.c
Chris Wilson a33b1dc8a7 drm/i915/query: nospec expects no more than an unsigned long
nospec quite reasonably asserts that it will never be used with an index
larger than unsigned long (that being the largest possibly index into an
C array). However, our ubi uses the convention of u64 for any large
integer, running afoul of the assertion on 32b. Reduce our index to an
unsigned long, checking for type overflow first.

  drivers/gpu/drm/i915/i915_query.c: In function 'i915_query_ioctl':
  include/linux/compiler.h:339:38: error: call to '__compiletime_assert_119' declared with attribute error: BUILD_BUG_ON failed: sizeof(_s) > sizeof(long)

Reported-by: kbuild-all@01.org
Fixes: 84b510e22d ("drm/i915/query: Protect tainted function pointer lookup")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180522121018.15199-1-chris@chris-wilson.co.uk
2018-05-22 16:55:57 +01:00

133 lines
3.5 KiB
C

/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2018 Intel Corporation
*/
#include <linux/nospec.h>
#include "i915_drv.h"
#include "i915_query.h"
#include <uapi/drm/i915_drm.h>
static int query_topology_info(struct drm_i915_private *dev_priv,
struct drm_i915_query_item *query_item)
{
const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
struct drm_i915_query_topology_info topo;
u32 slice_length, subslice_length, eu_length, total_length;
if (query_item->flags != 0)
return -EINVAL;
if (sseu->max_slices == 0)
return -ENODEV;
BUILD_BUG_ON(sizeof(u8) != sizeof(sseu->slice_mask));
slice_length = sizeof(sseu->slice_mask);
subslice_length = sseu->max_slices *
DIV_ROUND_UP(sseu->max_subslices,
sizeof(sseu->subslice_mask[0]) * BITS_PER_BYTE);
eu_length = sseu->max_slices * sseu->max_subslices *
DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE);
total_length = sizeof(topo) + slice_length + subslice_length + eu_length;
if (query_item->length == 0)
return total_length;
if (query_item->length < total_length)
return -EINVAL;
if (copy_from_user(&topo, u64_to_user_ptr(query_item->data_ptr),
sizeof(topo)))
return -EFAULT;
if (topo.flags != 0)
return -EINVAL;
if (!access_ok(VERIFY_WRITE, u64_to_user_ptr(query_item->data_ptr),
total_length))
return -EFAULT;
memset(&topo, 0, sizeof(topo));
topo.max_slices = sseu->max_slices;
topo.max_subslices = sseu->max_subslices;
topo.max_eus_per_subslice = sseu->max_eus_per_subslice;
topo.subslice_offset = slice_length;
topo.subslice_stride = DIV_ROUND_UP(sseu->max_subslices, BITS_PER_BYTE);
topo.eu_offset = slice_length + subslice_length;
topo.eu_stride =
DIV_ROUND_UP(sseu->max_eus_per_subslice, BITS_PER_BYTE);
if (__copy_to_user(u64_to_user_ptr(query_item->data_ptr),
&topo, sizeof(topo)))
return -EFAULT;
if (__copy_to_user(u64_to_user_ptr(query_item->data_ptr + sizeof(topo)),
&sseu->slice_mask, slice_length))
return -EFAULT;
if (__copy_to_user(u64_to_user_ptr(query_item->data_ptr +
sizeof(topo) + slice_length),
sseu->subslice_mask, subslice_length))
return -EFAULT;
if (__copy_to_user(u64_to_user_ptr(query_item->data_ptr +
sizeof(topo) +
slice_length + subslice_length),
sseu->eu_mask, eu_length))
return -EFAULT;
return total_length;
}
static int (* const i915_query_funcs[])(struct drm_i915_private *dev_priv,
struct drm_i915_query_item *query_item) = {
query_topology_info,
};
int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
{
struct drm_i915_private *dev_priv = to_i915(dev);
struct drm_i915_query *args = data;
struct drm_i915_query_item __user *user_item_ptr =
u64_to_user_ptr(args->items_ptr);
u32 i;
if (args->flags != 0)
return -EINVAL;
for (i = 0; i < args->num_items; i++, user_item_ptr++) {
struct drm_i915_query_item item;
unsigned long func_idx;
int ret;
if (copy_from_user(&item, user_item_ptr, sizeof(item)))
return -EFAULT;
if (item.query_id == 0)
return -EINVAL;
if (overflows_type(item.query_id - 1, unsigned long))
return -EINVAL;
func_idx = item.query_id - 1;
ret = -EINVAL;
if (func_idx < ARRAY_SIZE(i915_query_funcs)) {
func_idx = array_index_nospec(func_idx,
ARRAY_SIZE(i915_query_funcs));
ret = i915_query_funcs[func_idx](dev_priv, &item);
}
/* Only write the length back to userspace if they differ. */
if (ret != item.length && put_user(ret, &user_item_ptr->length))
return -EFAULT;
}
return 0;
}