Add a minimum-length check for the AMDGPU_CHUNK_ID_CP_GFX_SHADOW chunk in amdgpu_cs_pass1(), matching the gate already present for the IB, FENCE and BO_HANDLES chunk types.
The CP_GFX_SHADOW case previously shared a bare break with the dependency and syncobj chunk types, which do not dereference a fixed-size struct. When userspace submits this chunk with length_dw == 0, vmemdup_array_user() is called with size 0 and returns ZERO_SIZE_PTR, which passes the IS_ERR() check. amdgpu_cs_p2_shadow() then dereferences chunk->kdata as a struct drm_amdgpu_cs_chunk_cp_gfx_shadow (reading shadow->flags), faulting on the ZERO_SIZE_PTR and causing a NULL-pointer dereference. This is reachable by an unprivileged process in the render group. Reject undersized chunks with -EINVAL during pass1 so the bad submission is rejected before pass2 ever dereferences the data. Signed-off-by: Mario Limonciello <[email protected]> --- drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c index 0416827b4bb45..d63fbc7c568de 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c @@ -248,13 +248,17 @@ static int amdgpu_cs_pass1(struct amdgpu_cs_parser *p, goto free_partial_kdata; break; + case AMDGPU_CHUNK_ID_CP_GFX_SHADOW: + if (size < sizeof(struct drm_amdgpu_cs_chunk_cp_gfx_shadow)) + goto free_partial_kdata; + break; + case AMDGPU_CHUNK_ID_DEPENDENCIES: case AMDGPU_CHUNK_ID_SYNCOBJ_IN: case AMDGPU_CHUNK_ID_SYNCOBJ_OUT: case AMDGPU_CHUNK_ID_SCHEDULED_DEPENDENCIES: case AMDGPU_CHUNK_ID_SYNCOBJ_TIMELINE_WAIT: case AMDGPU_CHUNK_ID_SYNCOBJ_TIMELINE_SIGNAL: - case AMDGPU_CHUNK_ID_CP_GFX_SHADOW: break; default: -- 2.43.0
