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 <[email protected]>
---
drivers/gpu/drm/drm_bufs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index fcca21e8efac..4fe2363b1e34 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -734,7 +734,7 @@ int drm_legacy_addbufs_agp(struct drm_device *dev,
int i, valid;
struct drm_buf **temp_buflist;
- if (!dma)
+ if (!dma || !dev->agp)
return -EINVAL;
count = request->count;
--
2.25.1
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 <[email protected]>
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?
-Daniel
> ---
> drivers/gpu/drm/drm_bufs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
> index fcca21e8efac..4fe2363b1e34 100644
> --- a/drivers/gpu/drm/drm_bufs.c
> +++ b/drivers/gpu/drm/drm_bufs.c
> @@ -734,7 +734,7 @@ int drm_legacy_addbufs_agp(struct drm_device *dev,
> int i, valid;
> struct drm_buf **temp_buflist;
>
> - if (!dma)
> + if (!dma || !dev->agp)
> return -EINVAL;
>
> count = request->count;
> --
> 2.25.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
On Thu, Mar 17, 2022 at 6:49 PM Daniel Vetter <[email protected]> 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 <[email protected]>
>
> 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?
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
On Tue, Mar 22, 2022 at 10:27 PM Daniel Vetter <[email protected]> wrote:
>
> On Mon, Mar 21, 2022 at 09:02:47PM +0800, Zheyu Ma wrote:
> > On Thu, Mar 17, 2022 at 6:49 PM Daniel Vetter <[email protected]> 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 <[email protected]>
> > >
> > > 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).
Thanks for your explanation! I will pay attention next time.
Regards,
Zheyu Ma
On Mon, Mar 21, 2022 at 09:02:47PM +0800, Zheyu Ma wrote:
> On Thu, Mar 17, 2022 at 6:49 PM Daniel Vetter <[email protected]> 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 <[email protected]>
> >
> > 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