[PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl

[Min Li]

Userspace can guess the id value and try to race oa_config object creation
with config remove, resulting in a use-after-free if we dereference the
object after unlocking the metrics_lock.  For that reason, unlocking the
metrics_lock must be done after we are done dereferencing the object.

Signed-off-by: Min Li 
---
 drivers/gpu/drm/i915/i915_perf.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 824a34ec0b83..93748ca2c5da 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -4634,13 +4634,13 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, 
void *data,
err = oa_config->id;
goto sysfs_err;
}
-
-   mutex_unlock(&perf->metrics_lock);
+   id = oa_config->id;
 
drm_dbg(&perf->i915->drm,
"Added config %s id=%i\n", oa_config->uuid, oa_config->id);
+   mutex_unlock(&perf->metrics_lock);
 
-   return oa_config->id;
+   return id;
 
 sysfs_err:
mutex_unlock(&perf->metrics_lock);
-- 
2.25.1

[PATCH] drm/exynos: fix race condition UAF in exynos_g2d_exec_ioctl

[Min Li]

If it is async, runqueue_node is freed in g2d_runqueue_worker on another
worker thread. So in extreme cases, if g2d_runqueue_worker runs first, and
then executes the following if statement, there will be use-after-free.

Signed-off-by: Min Li 
---
 drivers/gpu/drm/exynos/exynos_drm_g2d.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c 
b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
index ec784e58da5c..414e585ec7dd 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
@@ -1335,7 +1335,7 @@ int exynos_g2d_exec_ioctl(struct drm_device *drm_dev, 
void *data,
/* Let the runqueue know that there is work to do. */
queue_work(g2d->g2d_workq, &g2d->runqueue_work);
 
-   if (runqueue_node->async)
+   if (req->async)
goto out;
 
wait_for_completion(&runqueue_node->complete);
-- 
2.34.1

[PATCH] drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

[Min Li]

Userspace can race to free the gobj(robj converted from), robj should not
be accessed again after drm_gem_object_put, otherwith it will result in
use-after-free.

Signed-off-by: Min Li 
---
 drivers/gpu/drm/radeon/radeon_gem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c 
b/drivers/gpu/drm/radeon/radeon_gem.c
index bdc5af23f005..450c7cbdd28a 100644
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -478,7 +478,7 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, 
void *data,
 
drm_gem_object_put(gobj);
up_read(&rdev->exclusive_lock);
-   r = radeon_gem_handle_lockup(robj->rdev, r);
+   r = radeon_gem_handle_lockup(rdev, r);
return r;
 }
 
-- 
2.34.1

[PATCH v2] drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

[Min Li]

Userspace can race to free the gobj(robj converted from), robj should not
be accessed again after drm_gem_object_put, otherwith it will result in
use-after-free.

Signed-off-by: Min Li 
---
Changes in v2:
- Remove unused robj, avoid compile complain

 drivers/gpu/drm/radeon/radeon_gem.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c 
b/drivers/gpu/drm/radeon/radeon_gem.c
index bdc5af23f005..d3f5ddbc1704 100644
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -459,7 +459,6 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, 
void *data,
struct radeon_device *rdev = dev->dev_private;
struct drm_radeon_gem_set_domain *args = data;
struct drm_gem_object *gobj;
-   struct radeon_bo *robj;
int r;
 
/* for now if someone requests domain CPU -
@@ -472,13 +471,12 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, 
void *data,
up_read(&rdev->exclusive_lock);
return -ENOENT;
}
-   robj = gem_to_radeon_bo(gobj);
 
r = radeon_gem_set_domain(gobj, args->read_domains, args->write_domain);
 
drm_gem_object_put(gobj);
up_read(&rdev->exclusive_lock);
-   r = radeon_gem_handle_lockup(robj->rdev, r);
+   r = radeon_gem_handle_lockup(rdev, r);
return r;
 }
 
-- 
2.34.1