[Nouveau] [PATCH] drm/nouveau: Fix out-of-bounds access when deferencing MMU type

Wed Nov 11 12:08:03 UTC 2020

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.

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.

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