On Mon, Mar 21, 2022 at 09:02:47PM +0800, Zheyu Ma wrote: > On Thu, Mar 17, 2022 at 6:49 PM Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > On Fri, Mar 11, 2022 at 07:23:02AM +0000, Zheyu Ma wrote: > > > The user program can control the 'drm_buf_desc::flags' via ioctl system > > > call and enter the function drm_legacy_addbufs_agp(). If the driver > > > doesn't initialize the agp resources, the driver will cause a null > > > pointer dereference. > > > > > > The following log reveals it: > > > general protection fault, probably for non-canonical address > > > 0xdffffc000000000f: 0000 [#1] PREEMPT SMP KASAN PTI > > > KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f] > > > Call Trace: > > > <TASK> > > > drm_ioctl_kernel+0x342/0x450 drivers/gpu/drm/drm_ioctl.c:785 > > > drm_ioctl+0x592/0x940 drivers/gpu/drm/drm_ioctl.c:885 > > > vfs_ioctl fs/ioctl.c:51 [inline] > > > __do_sys_ioctl fs/ioctl.c:874 [inline] > > > __se_sys_ioctl+0xaa/0xf0 fs/ioctl.c:860 > > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > > do_syscall_64+0x43/0x90 arch/x86/entry/common.c:80 > > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > > > > > Fix this bug by adding a check. > > > > > > Signed-off-by: Zheyu Ma <zheyuma97@xxxxxxxxx> > > > > You can only hit this if you enabled a DRIVER_LEGACY drm driver, which > > opens you up to tons of other CVEs and issues. What's your .config? > > Yes, I enable the DRM_LEGACY option in the config. > I think you mean this is not a normal configuration file? Do you have > a recommended configuration option for when I want to test the GPU > driver? Yeah DRM_LEGACY gives you all kinds of horrible and known-broken interfaces. Don't enable that :-) You have a bunch of other drivers enable which require DRM_LEGACY, so those will disable too. Anything else I think would be an upstream bug and we'd need to adjust Kconfig (or fix the code). Cheers, Daniel > > Actually, I use the following configs related to GPU: > > CONFIG_AGP=y > CONFIG_AGP_AMD64=y > CONFIG_AGP_INTEL=y > CONFIG_AGP_SIS=y > CONFIG_AGP_VIA=y > CONFIG_INTEL_GTT=y > CONFIG_VGA_ARB=y > CONFIG_VGA_ARB_MAX_GPUS=16 > CONFIG_DRM=y > CONFIG_DRM_MIPI_DSI=y > CONFIG_DRM_KMS_HELPER=y > CONFIG_DRM_DEBUG_MODESET_LOCK=y > CONFIG_DRM_FBDEV_EMULATION=y > CONFIG_DRM_FBDEV_OVERALLOC=100 > CONFIG_DRM_TTM=y > CONFIG_DRM_VRAM_HELPER=y > CONFIG_DRM_TTM_HELPER=y > CONFIG_DRM_GEM_SHMEM_HELPER=y > CONFIG_DRM_SCHED=y > CONFIG_DRM_RADEON=y > CONFIG_DRM_AMDGPU=y > CONFIG_DRM_AMD_DC=y > CONFIG_DRM_AMD_DC_DCN=y > CONFIG_DRM_I915=y > CONFIG_DRM_I915_FORCE_PROBE="" > CONFIG_DRM_I915_CAPTURE_ERROR=y > CONFIG_DRM_I915_COMPRESS_ERROR=y > CONFIG_DRM_I915_USERPTR=y > CONFIG_DRM_I915_REQUEST_TIMEOUT=20000 > CONFIG_DRM_I915_FENCE_TIMEOUT=10000 > CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND=250 > CONFIG_DRM_I915_HEARTBEAT_INTERVAL=2500 > CONFIG_DRM_I915_PREEMPT_TIMEOUT=640 > CONFIG_DRM_I915_MAX_REQUEST_BUSYWAIT=8000 > CONFIG_DRM_I915_STOP_TIMEOUT=100 > CONFIG_DRM_I915_TIMESLICE_DURATION=1 > CONFIG_DRM_VMWGFX=y > CONFIG_DRM_GMA500=y > CONFIG_DRM_UDL=y > CONFIG_DRM_AST=y > CONFIG_DRM_MGAG200=y > CONFIG_DRM_QXL=y > CONFIG_DRM_VIRTIO_GPU=y > CONFIG_DRM_PANEL=y > CONFIG_DRM_BRIDGE=y > CONFIG_DRM_PANEL_BRIDGE=y > CONFIG_DRM_BOCHS=y > CONFIG_DRM_CIRRUS_QEMU=y > CONFIG_DRM_GM12U320=y > CONFIG_DRM_VBOXVIDEO=y > CONFIG_DRM_GUD=y > CONFIG_DRM_HYPERV=y > CONFIG_DRM_LEGACY=y > CONFIG_DRM_TDFX=y > CONFIG_DRM_R128=y > CONFIG_DRM_MGA=y > CONFIG_DRM_SIS=y > CONFIG_DRM_VIA=y > CONFIG_DRM_SAVAGE=y > CONFIG_DRM_PANEL_ORIENTATION_QUIRKS=y > > Thanks, > Zheyu Ma -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
