[PATCH] drm/nouveau: Fix out-of-bounds access when deferencing MMU type
Ben Skeggs
skeggsb at gmail.com
Thu Nov 12 02:38:52 UTC 2020
On Thu, 12 Nov 2020 at 02:27, Ruhl, Michael J <michael.j.ruhl at intel.com> wrote:
>
> >-----Original Message-----
> >From: Thomas Zimmermann <tzimmermann at suse.de>
> >Sent: Wednesday, November 11, 2020 7:08 AM
> >To: Ruhl, Michael J <michael.j.ruhl at intel.com>; bskeggs at redhat.com;
> >airlied at linux.ie; daniel at ffwll.ch; christian.koenig at amd.com
> >Cc: nouveau at lists.freedesktop.org; dri-devel at lists.freedesktop.org;
> >Maarten Lankhorst <maarten.lankhorst at linux.intel.com>; Maxime Ripard
> ><mripard at kernel.org>; Dave Airlie <airlied at redhat.com>; Gerd Hoffmann
> ><kraxel at redhat.com>; Alex Deucher <alexander.deucher at amd.com>;
> >VMware Graphics <linux-graphics-maintainer at vmware.com>; Roland
> >Scheidegger <sroland at vmware.com>; Huang Rui <ray.huang at amd.com>;
> >Felix Kuehling <Felix.Kuehling at amd.com>; Hawking Zhang
> ><Hawking.Zhang at amd.com>; Jason Gunthorpe <jgg at ziepe.ca>; Likun Gao
> ><Likun.Gao at amd.com>; virtualization at lists.linux-foundation.org; spice-
> >devel at lists.freedesktop.org; amd-gfx at lists.freedesktop.org
> >Subject: Re: [PATCH] drm/nouveau: Fix out-of-bounds access when
> >deferencing MMU type
> >
> >Hi
> >
> >Am 10.11.20 um 16:27 schrieb Ruhl, Michael J:
> >>
> >>
> >>> -----Original Message-----
> >>> From: Thomas Zimmermann <tzimmermann at suse.de>
> >>> Sent: Tuesday, November 10, 2020 8:37 AM
> >>> To: bskeggs at redhat.com; airlied at linux.ie; daniel at ffwll.ch; Ruhl, Michael J
> >>> <michael.j.ruhl at intel.com>; christian.koenig at amd.com
> >>> Cc: nouveau at lists.freedesktop.org; dri-devel at lists.freedesktop.org;
> >Thomas
> >>> Zimmermann <tzimmermann at suse.de>; Maarten Lankhorst
> >>> <maarten.lankhorst at linux.intel.com>; Maxime Ripard
> >>> <mripard at kernel.org>; Dave Airlie <airlied at redhat.com>; Gerd Hoffmann
> >>> <kraxel at redhat.com>; Alex Deucher <alexander.deucher at amd.com>;
> >>> VMware Graphics <linux-graphics-maintainer at vmware.com>; Roland
> >>> Scheidegger <sroland at vmware.com>; Huang Rui <ray.huang at amd.com>;
> >>> Felix Kuehling <Felix.Kuehling at amd.com>; Hawking Zhang
> >>> <Hawking.Zhang at amd.com>; Jason Gunthorpe <jgg at ziepe.ca>; Likun
> >Gao
> >>> <Likun.Gao at amd.com>; virtualization at lists.linux-foundation.org; spice-
> >>> devel at lists.freedesktop.org; amd-gfx at lists.freedesktop.org
> >>> Subject: [PATCH] drm/nouveau: Fix out-of-bounds access when
> >deferencing
> >>> MMU type
> >>>
> >>> The value of struct drm_device.ttm.type_vram can become -1 for
> >unknown
> >>> types of memory (see nouveau_ttm_init()). This leads to an out-of-bounds
> >>> error when accessing struct nvif_mmu.type[]:
> >>
> >> Would this make more sense to just set the type_vram = 0 instead of -1?
> >
> >From what I understand, these indices refer to an internal type of MMU,
> >rsp the MMU's capabilities. However, my hardware (pre-NV50) does not
> >have an MMU at all.
>
> Yeah, and upon further review I see that my comment was completely wrong
> (value vs. index).
>
> A better suggestion would have been, create an entry in the array that means,
> "unsupported type" with a value of 0, but...
>
> >I agree that it would be nice to have a cleaner design that incorporates
> >this case, but resolving that would apparently require more than a bugfix.
>
> I agree. The -1 index is a special case for the platform path
> (platform != NV_DEVICE_INFO_V0_SOC). This is a fix for the issue, but not
> a complete solution.
>
> If you need it:
> Reviewed-by: Michael J. Ruhl <michael.j.ruhl at intel.com>
I've put an alternate fix for this here[1], and will get it into
drm-fixes later today.
Ben.
[1] https://github.com/skeggsb/nouveau/commit/4590f7120c2f1f4aea9d8b93a2dae43b312d35ad
>
> Thanks,
> Mike
>
> >Best regards
> >Thomas
> >
> >>
> >> Mike
> >>
> >>>
> >>> [ 18.304116]
> >>>
> >===========================================================
> >>> =======
> >>> [ 18.311649] BUG: KASAN: slab-out-of-bounds in
> >>> nouveau_ttm_io_mem_reserve+0x17a/0x7e0 [nouveau]
> >>> [ 18.320415] Read of size 1 at addr ffff88810ffac1fe by task systemd-
> >>> udevd/342
> >>> [ 18.327681]
> >>> [ 18.329208] CPU: 1 PID: 342 Comm: systemd-udevd Tainted: G E
> >>> 5.10.0-rc2-1-default+ #581
> >>> [ 18.338681] Hardware name: Dell Inc. OptiPlex 9020/0N4YC8, BIOS A24
> >>> 10/24/2018
> >>> [ 18.346032] Call Trace:
> >>> [ 18.348536] dump_stack+0xae/0xe5
> >>> [ 18.351919] print_address_description.constprop.0+0x17/0xf0
> >>> [ 18.357787] ? nouveau_ttm_io_mem_reserve+0x17a/0x7e0 [nouveau]
> >>> [ 18.363818] __kasan_report.cold+0x20/0x38
> >>> [ 18.368099] ? nouveau_ttm_io_mem_reserve+0x17a/0x7e0 [nouveau]
> >>> [ 18.374133] kasan_report+0x3a/0x50
> >>> [ 18.377789] nouveau_ttm_io_mem_reserve+0x17a/0x7e0 [nouveau]
> >>> <...>
> >>> [ 18.767690] Allocated by task 342:
> >>> [ 18.773087] kasan_save_stack+0x1b/0x40
> >>> [ 18.778890] __kasan_kmalloc.constprop.0+0xbf/0xd0
> >>> [ 18.785646] __kmalloc_track_caller+0x1be/0x390
> >>> [ 18.792165] kstrdup_const+0x46/0x70
> >>> [ 18.797686] kobject_set_name_vargs+0x2f/0xb0
> >>> [ 18.803992] kobject_init_and_add+0x9d/0xf0
> >>> [ 18.810117] ttm_mem_global_init+0x12c/0x210 [ttm]
> >>> [ 18.816853] ttm_bo_global_init+0x4a/0x160 [ttm]
> >>> [ 18.823420] ttm_bo_device_init+0x39/0x220 [ttm]
> >>> [ 18.830046] nouveau_ttm_init+0x2c3/0x830 [nouveau]
> >>> [ 18.836929] nouveau_drm_device_init+0x1b4/0x3f0 [nouveau]
> >>> <...>
> >>> [ 19.105336]
> >>>
> >===========================================================
> >>> =======
> >>>
> >>> Fix this error, by not using type_vram as an index if it's negative.
> >>> Assume default values instead.
> >>>
> >>> The error was seen on Nvidia G72 hardware.
> >>>
> >>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> >>> Fixes: 1cf65c45183a ("drm/ttm: add caching state to ttm_bus_placement")
> >>> Cc: Christian König <christian.koenig at amd.com>
> >>> Cc: Michael J. Ruhl <michael.j.ruhl at intel.com>
> >>> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> >>> Cc: Maxime Ripard <mripard at kernel.org>
> >>> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> >>> Cc: David Airlie <airlied at linux.ie>
> >>> Cc: Daniel Vetter <daniel at ffwll.ch>
> >>> Cc: Ben Skeggs <bskeggs at redhat.com>
> >>> Cc: Dave Airlie <airlied at redhat.com>
> >>> Cc: Gerd Hoffmann <kraxel at redhat.com>
> >>> Cc: Alex Deucher <alexander.deucher at amd.com>
> >>> Cc: "Christian König" <christian.koenig at amd.com>
> >>> Cc: VMware Graphics <linux-graphics-maintainer at vmware.com>
> >>> Cc: Roland Scheidegger <sroland at vmware.com>
> >>> Cc: Huang Rui <ray.huang at amd.com>
> >>> Cc: Felix Kuehling <Felix.Kuehling at amd.com>
> >>> Cc: Hawking Zhang <Hawking.Zhang at amd.com>
> >>> Cc: Jason Gunthorpe <jgg at ziepe.ca>
> >>> Cc: Likun Gao <Likun.Gao at amd.com>
> >>> Cc: dri-devel at lists.freedesktop.org
> >>> Cc: nouveau at lists.freedesktop.org
> >>> Cc: virtualization at lists.linux-foundation.org
> >>> Cc: spice-devel at lists.freedesktop.org
> >>> Cc: amd-gfx at lists.freedesktop.org
> >>> ---
> >>> drivers/gpu/drm/nouveau/nouveau_bo.c | 5 ++++-
> >>> 1 file changed, 4 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c
> >>> b/drivers/gpu/drm/nouveau/nouveau_bo.c
> >>> index 8133377d865d..fe15299d417e 100644
> >>> --- a/drivers/gpu/drm/nouveau/nouveau_bo.c
> >>> +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
> >>> @@ -1142,9 +1142,12 @@ nouveau_ttm_io_mem_reserve(struct
> >>> ttm_bo_device *bdev, struct ttm_resource *reg)
> >>> struct nvkm_device *device = nvxx_device(&drm->client.device);
> >>> struct nouveau_mem *mem = nouveau_mem(reg);
> >>> struct nvif_mmu *mmu = &drm->client.mmu;
> >>> - const u8 type = mmu->type[drm->ttm.type_vram].type;
> >>> + u8 type = 0;
> >>> int ret;
> >>>
> >>> + if (drm->ttm.type_vram >= 0)
> >>> + type = mmu->type[drm->ttm.type_vram].type;
> >>> +
> >>> mutex_lock(&drm->ttm.io_reserve_mutex);
> >>> retry:
> >>> switch (reg->mem_type) {
> >>> --
> >>> 2.29.2
> >>
> >
> >--
> >Thomas Zimmermann
> >Graphics Driver Developer
> >SUSE Software Solutions Germany GmbH
> >Maxfeldstr. 5, 90409 Nürnberg, Germany
> >(HRB 36809, AG Nürnberg)
> >Geschäftsführer: Felix Imendörffer
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