i915_drm.h now defines the format of the returned
DRM_I915_QUERY_HWCONFIG_BLOB query item. Since i915 receives this from
the black box GuC software, it should verify that the data matches
that format before sending it to user-space.
The verification makes a single simple pass through the blob contents,
so this verification step should not add a significant amount of init
time to i915.
v3:
* Add various changes suggested by Tvrtko
v4:
* Rewrite verify_hwconfig_blob() to hopefully be clearer without
relying on comments so much, and add various suggestions from
Michal.
v6:
* Rework based on John's updated "drm/i915/guc: Add fetch of hwconfig
table" v2 which stores the hwconfig blob at the GT level.
Signed-off-by: Jordan Justen <jordan.l.justen@xxxxxxxxx>
Acked-by: Jon Bloomfield <jon.bloomfield@xxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
.../gpu/drm/i915/gt/uc/intel_guc_hwconfig.c | 43 ++++++++++++++++++-
1 file changed, 42 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_hwconfig.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_hwconfig.c
index e0f65bdd1c84..1a3134d3d434 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_hwconfig.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_hwconfig.c
@@ -68,8 +68,44 @@ static int guc_hwconfig_discover_size(struct intel_guc *guc, struct intel_hwconf
return 0;
}
+static int verify_hwconfig_blob(struct intel_guc *guc, struct intel_hwconfig *hwconfig)
+{
+ struct drm_device *drm = &guc_to_gt(guc)->i915->drm;
+ struct drm_i915_query_hwconfig_blob_item *item = hwconfig->ptr;
+ u64 offset = 0;
+ u64 remaining = hwconfig->size;
+ /* Everything before the data field is required */
+ u64 min_item_size = offsetof(struct drm_i915_query_hwconfig_blob_item, data);
+ u64 item_size;
+
+ if (!IS_ALIGNED(hwconfig->size, sizeof(u32))) {
+ drm_err(drm, "hwconfig blob size (%d) is not u32 aligned\n", hwconfig->size);
+ return -EINVAL;
+ }
+
+ while (offset < hwconfig->size) {
+ if (remaining < min_item_size) {
+ drm_err(drm, "hwconfig blob invalid (no room for item required fields at offset %lld)\n",
+ offset);
+ return -EINVAL;
+ }
+ item_size = min_item_size + sizeof(u32) * item->length;
+ if (item_size > remaining) {
+ drm_err(drm, "hwconfig blob invalid (no room for data array of item at offset %lld)\n",
+ offset);
+ return -EINVAL;
+ }
+ offset += item_size;
+ remaining -= item_size;
+ item = (void *)&item->data[item->length];
+ }
+
+ return 0;
+}
+
static int guc_hwconfig_fill_buffer(struct intel_guc *guc, struct intel_hwconfig *hwconfig)
{
+ struct drm_device *drm = &guc_to_gt(guc)->i915->drm;
struct i915_vma *vma;
u32 ggtt_offset;
void *vaddr;
@@ -84,8 +120,13 @@ static int guc_hwconfig_fill_buffer(struct intel_guc *guc, struct intel_hwconfig
ggtt_offset = intel_guc_ggtt_offset(guc, vma);
ret = __guc_action_get_hwconfig(guc, ggtt_offset, hwconfig->size);
- if (ret >= 0)
+ if (ret >= 0) {
memcpy(hwconfig->ptr, vaddr, hwconfig->size);
+ if (verify_hwconfig_blob(guc, hwconfig)) {
+ drm_err(drm, "Ignoring invalid hwconfig blob received from GuC!\n");
+ ret = -EINVAL;
+ }
+ }
i915_vma_unpin_and_release(&vma, I915_VMA_RELEASE_MAP);
--
2.34.1
