[PATCH v2 2/2] drm: Make Legacy Context access functions optional.

Peter Antoine
2015-05-13T06:55:14Z

As these functions are only used by one driver and there are security holes
in these functions. Make the functions optional.

These changes are based on the two patches:
commit c21eb21cb50d58e7cbdcb8b9e7ff68b85cfa5095
Author: Dave Airlie <airlied@redhat.com>

And the commit that the above patch reverts:
commit 7c510133d93dd6f15ca040733ba7b2891ed61fd1
Author: Daniel Vetter <daniel.vetter@ffwll.ch>

This should now turn off the context feature.

Issue: VIZ-5485
Signed-off-by: Peter Antoine <peter.antoine@intel.com>
---
drivers/gpu/drm/drm_context.c | 36 ++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/drm_drv.c | 12 +++++++-----
2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c
index 9b23525..574be2a 100644
--- a/drivers/gpu/drm/drm_context.c
+++ b/drivers/gpu/drm/drm_context.c
@@ -53,6 +53,9 @@ struct drm_ctx_list {
*/
void drm_legacy_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
{
+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
mutex_lock(&dev->struct_mutex);
idr_remove(&dev->ctx_idr, ctx_handle);
mutex_unlock(&dev->struct_mutex);
@@ -87,6 +90,9 @@ static int drm_legacy_ctxbitmap_next(struct drm_device * dev)
*/
int drm_legacy_ctxbitmap_init(struct drm_device * dev)
{
+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
idr_init(&dev->ctx_idr);
return 0;
}
@@ -101,6 +107,9 @@ int drm_legacy_ctxbitmap_init(struct drm_device * dev)
*/
void drm_legacy_ctxbitmap_cleanup(struct drm_device * dev)
{
+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
mutex_lock(&dev->struct_mutex);
idr_destroy(&dev->ctx_idr);
mutex_unlock(&dev->struct_mutex);
@@ -119,6 +128,9 @@ void drm_legacy_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
{
struct drm_ctx_list *pos, *tmp;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
mutex_lock(&dev->ctxlist_mutex);

list_for_each_entry_safe(pos, tmp, &dev->ctxlist, head) {
@@ -161,6 +173,9 @@ int drm_legacy_getsareactx(struct drm_device *dev, void *data,
struct drm_local_map *map;
struct drm_map_list *_entry;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
mutex_lock(&dev->struct_mutex);

map = idr_find(&dev->ctx_idr, request->ctx_id);
@@ -205,6 +220,9 @@ int drm_legacy_setsareactx(struct drm_device *dev, void *data,
struct drm_local_map *map = NULL;
struct drm_map_list *r_list = NULL;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
mutex_lock(&dev->struct_mutex);
list_for_each_entry(r_list, &dev->maplist, head) {
if (r_list->map
@@ -305,6 +323,9 @@ int drm_legacy_resctx(struct drm_device *dev, void *data,
struct drm_ctx ctx;
int i;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
if (res->count >= DRM_RESERVED_CONTEXTS) {
memset(&ctx, 0, sizeof(ctx));
for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
@@ -335,6 +356,9 @@ int drm_legacy_addctx(struct drm_device *dev, void *data,
struct drm_ctx_list *ctx_entry;
struct drm_ctx *ctx = data;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
ctx->handle = drm_legacy_ctxbitmap_next(dev);
if (ctx->handle == DRM_KERNEL_CONTEXT) {
/* Skip kernel's context and get a new one. */
@@ -378,6 +402,9 @@ int drm_legacy_getctx(struct drm_device *dev, void *data,
{
struct drm_ctx *ctx = data;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
/* This is 0, because we don't handle any context flags */
ctx->flags = 0;

@@ -400,6 +427,9 @@ int drm_legacy_switchctx(struct drm_device *dev, void *data,
{
struct drm_ctx *ctx = data;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
DRM_DEBUG("%d\n", ctx->handle);
return drm_context_switch(dev, dev->last_context, ctx->handle);
}
@@ -420,6 +450,9 @@ int drm_legacy_newctx(struct drm_device *dev, void *data,
{
struct drm_ctx *ctx = data;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
DRM_DEBUG("%d\n", ctx->handle);
drm_context_switch_complete(dev, file_priv, ctx->handle);

@@ -442,6 +475,9 @@ int drm_legacy_rmctx(struct drm_device *dev, void *data,
{
struct drm_ctx *ctx = data;

+ if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ return -EINVAL;
+
DRM_DEBUG("%d\n", ctx->handle);
if (ctx->handle != DRM_KERNEL_CONTEXT) {
if (dev->driver->context_dtor)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 3b3c4f5..1de2df8 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -584,11 +584,13 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
if (drm_ht_create(&dev->map_hash, 12))
goto err_minors;

- ret = drm_legacy_ctxbitmap_init(dev);
- if (ret) {
- DRM_ERROR("Cannot allocate memory for context bitmap.\n");
- goto err_ht;
- }
+ if (drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT))
+ ret = drm_legacy_ctxbitmap_init(dev);
+ if (ret) {
+ DRM_ERROR(
+ "Cannot allocate memory for context bitmap.\n");
+ goto err_ht;
+ }

if (drm_core_check_feature(dev, DRIVER_GEM)) {
ret = drm_gem_init(dev);
--
1.9.1