[PATCH 4.19 337/338] drm/amdgpu: Check if fd really is an amdgpu fd.

Greg Kroah-Hartman
2022-04-14T14:02:09Z

From: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

commit 021830d24ba55a578f602979274965344c8e6284 upstream.

Otherwise we interpret the file private data as drm & amdgpu data
while it might not be, possibly allowing one to get memory corruption.

Signed-off-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 2 ++
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 16 ++++++++++++++++
drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c | 10 +++++++---
3 files changed, 25 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -955,6 +955,8 @@ struct amdgpu_gfx {
DECLARE_BITMAP (pipe_reserve_bitmap, AMDGPU_MAX_COMPUTE_QUEUES);
};

+int amdgpu_file_to_fpriv(struct file *filp, struct amdgpu_fpriv **fpriv);
+
int amdgpu_ib_get(struct amdgpu_device *adev, struct amdgpu_vm *vm,
unsigned size, struct amdgpu_ib *ib);
void amdgpu_ib_free(struct amdgpu_device *adev, struct amdgpu_ib *ib,
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -1132,6 +1132,22 @@ static const struct file_operations amdg
#endif
};

+int amdgpu_file_to_fpriv(struct file *filp, struct amdgpu_fpriv **fpriv)
+{
+ struct drm_file *file;
+
+ if (!filp)
+ return -EINVAL;
+
+ if (filp->f_op != &amdgpu_driver_kms_fops) {
+ return -EINVAL;
+ }
+
+ file = filp->private_data;
+ *fpriv = file->driver_priv;
+ return 0;
+}
+
static bool
amdgpu_get_crtc_scanout_position(struct drm_device *dev, unsigned int pipe,
bool in_vblank_irq, int *vpos, int *hpos,
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c
@@ -54,16 +54,20 @@ static int amdgpu_sched_process_priority
enum drm_sched_priority priority)
{
struct file *filp = fget(fd);
- struct drm_file *file;
struct amdgpu_fpriv *fpriv;
struct amdgpu_ctx *ctx;
uint32_t id;
+ int r;

if (!filp)
return -EINVAL;

- file = filp->private_data;
- fpriv = file->driver_priv;
+ r = amdgpu_file_to_fpriv(filp, &fpriv);
+ if (r) {
+ fput(filp);
+ return r;
+ }
+
idr_for_each_entry(&fpriv->ctx_mgr.ctx_handles, ctx, id)
amdgpu_ctx_priority_override(ctx, priority);