drivers/gpu/drm/drm_bufs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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@gmail.com>
---
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;
--
2.25.1On 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@gmail.com> 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 <daniel@ffwll.ch> 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@gmail.com> > > 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 Mon, Mar 21, 2022 at 09:02:47PM +0800, Zheyu Ma wrote: > On Thu, Mar 17, 2022 at 6:49 PM Daniel Vetter <daniel@ffwll.ch> 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@gmail.com> > > > > 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
On Tue, Mar 22, 2022 at 10:27 PM Daniel Vetter <daniel@ffwll.ch> 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 <daniel@ffwll.ch> 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@gmail.com> > > > > > > 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
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