linux_dsm_epyc7002/drivers/gpu/drm/radeon/radeon_cs.c
Jerome Glisse c8c15ff1e9 drm/radeon: r6xx/r7xx possible security issue, system ram access
This patch workaround a possible security issue which can allow
user to abuse drm on r6xx/r7xx hw to access any system ram memory.
This patch doesn't break userspace, it detect "valid" old use of
CB_COLOR[0-7]_FRAG & CB_COLOR[0-7]_TILE registers and overwritte
the address these registers are pointing to with the one of the
last color buffer. This workaround will work for old mesa &
xf86-video-ati and any old user which did use similar register
programming pattern as those (we expect that there is no others
user of those ioctl except possibly a malicious one). This patch
add a warning if it detects such usage, warning encourage people
to update their mesa & xf86-video-ati. New userspace will submit
proper relocation.

Fix for xf86-video-ati / mesa (this kernel patch is enough to
prevent abuse, fix for userspace are to set proper cs stream and
avoid kernel warning) :
http://cgit.freedesktop.org/xorg/driver/xf86-video-ati/commit/?id=95d63e408cc88b6934bec84a0b1ef94dfe8bee7b
http://cgit.freedesktop.org/mesa/mesa/commit/?id=46dc6fd3ed5ef96cda53641a97bc68c3bc104a9f

Abusing this register to perform system ram memory is not easy,
here is outline on how it could be achieve. First attacker must
have access to the drm device and be able to submit command stream
throught cs ioctl. Then attacker must build a proper command stream
for r6xx/r7xx hw which will abuse the FRAG or TILE buffer to
overwrite the GPU GART which is in VRAM. To achieve so attacker
as to setup CB_COLOR[0-7]_FRAG or CB_COLOR[0-7]_TILE to point
to the GPU GART, then it has to find a way to write predictable
value into those buffer (with little cleverness i believe this
can be done but this is an hard task). Once attacker have such
program it can overwritte GPU GART to program GPU gart to point
anywhere in system memory. It then can reusse same method as he
used to reprogram GART to overwritte the system ram through the
GART mapping. In the process the attacker has to be carefull to
not overwritte any sensitive area of the GART table, like ring
or IB gart entry as it will more then likely lead to GPU lockup.
Bottom line is that i think it's very hard to use this flaw
to get system ram access but in theory one can achieve so.

Side note: I am not aware of anyone ever using the GPU as an
attack vector, nevertheless we take great care in the opensource
driver to try to detect and forbid malicious use of GPU. I don't
think the closed source driver are as cautious as we are.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
2010-01-21 08:49:32 +10:00

344 lines
9.8 KiB
C

/*
* Copyright 2008 Jerome Glisse.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Authors:
* Jerome Glisse <glisse@freedesktop.org>
*/
#include "drmP.h"
#include "radeon_drm.h"
#include "radeon_reg.h"
#include "radeon.h"
void r100_cs_dump_packet(struct radeon_cs_parser *p,
struct radeon_cs_packet *pkt);
int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
{
struct drm_device *ddev = p->rdev->ddev;
struct radeon_cs_chunk *chunk;
unsigned i, j;
bool duplicate;
if (p->chunk_relocs_idx == -1) {
return 0;
}
chunk = &p->chunks[p->chunk_relocs_idx];
/* FIXME: we assume that each relocs use 4 dwords */
p->nrelocs = chunk->length_dw / 4;
p->relocs_ptr = kcalloc(p->nrelocs, sizeof(void *), GFP_KERNEL);
if (p->relocs_ptr == NULL) {
return -ENOMEM;
}
p->relocs = kcalloc(p->nrelocs, sizeof(struct radeon_cs_reloc), GFP_KERNEL);
if (p->relocs == NULL) {
return -ENOMEM;
}
for (i = 0; i < p->nrelocs; i++) {
struct drm_radeon_cs_reloc *r;
duplicate = false;
r = (struct drm_radeon_cs_reloc *)&chunk->kdata[i*4];
for (j = 0; j < p->nrelocs; j++) {
if (r->handle == p->relocs[j].handle) {
p->relocs_ptr[i] = &p->relocs[j];
duplicate = true;
break;
}
}
if (!duplicate) {
p->relocs[i].gobj = drm_gem_object_lookup(ddev,
p->filp,
r->handle);
if (p->relocs[i].gobj == NULL) {
DRM_ERROR("gem object lookup failed 0x%x\n",
r->handle);
return -EINVAL;
}
p->relocs_ptr[i] = &p->relocs[i];
p->relocs[i].robj = p->relocs[i].gobj->driver_private;
p->relocs[i].lobj.bo = p->relocs[i].robj;
p->relocs[i].lobj.rdomain = r->read_domains;
p->relocs[i].lobj.wdomain = r->write_domain;
p->relocs[i].handle = r->handle;
p->relocs[i].flags = r->flags;
INIT_LIST_HEAD(&p->relocs[i].lobj.list);
radeon_bo_list_add_object(&p->relocs[i].lobj,
&p->validated);
}
}
return radeon_bo_list_validate(&p->validated, p->ib->fence);
}
int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
{
struct drm_radeon_cs *cs = data;
uint64_t *chunk_array_ptr;
unsigned size, i;
if (!cs->num_chunks) {
return 0;
}
/* get chunks */
INIT_LIST_HEAD(&p->validated);
p->idx = 0;
p->chunk_ib_idx = -1;
p->chunk_relocs_idx = -1;
p->chunks_array = kcalloc(cs->num_chunks, sizeof(uint64_t), GFP_KERNEL);
if (p->chunks_array == NULL) {
return -ENOMEM;
}
chunk_array_ptr = (uint64_t *)(unsigned long)(cs->chunks);
if (DRM_COPY_FROM_USER(p->chunks_array, chunk_array_ptr,
sizeof(uint64_t)*cs->num_chunks)) {
return -EFAULT;
}
p->nchunks = cs->num_chunks;
p->chunks = kcalloc(p->nchunks, sizeof(struct radeon_cs_chunk), GFP_KERNEL);
if (p->chunks == NULL) {
return -ENOMEM;
}
for (i = 0; i < p->nchunks; i++) {
struct drm_radeon_cs_chunk __user **chunk_ptr = NULL;
struct drm_radeon_cs_chunk user_chunk;
uint32_t __user *cdata;
chunk_ptr = (void __user*)(unsigned long)p->chunks_array[i];
if (DRM_COPY_FROM_USER(&user_chunk, chunk_ptr,
sizeof(struct drm_radeon_cs_chunk))) {
return -EFAULT;
}
p->chunks[i].length_dw = user_chunk.length_dw;
p->chunks[i].kdata = NULL;
p->chunks[i].chunk_id = user_chunk.chunk_id;
if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_RELOCS) {
p->chunk_relocs_idx = i;
}
if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_IB) {
p->chunk_ib_idx = i;
/* zero length IB isn't useful */
if (p->chunks[i].length_dw == 0)
return -EINVAL;
}
p->chunks[i].length_dw = user_chunk.length_dw;
p->chunks[i].user_ptr = (void __user *)(unsigned long)user_chunk.chunk_data;
cdata = (uint32_t *)(unsigned long)user_chunk.chunk_data;
if (p->chunks[i].chunk_id != RADEON_CHUNK_ID_IB) {
size = p->chunks[i].length_dw * sizeof(uint32_t);
p->chunks[i].kdata = kmalloc(size, GFP_KERNEL);
if (p->chunks[i].kdata == NULL) {
return -ENOMEM;
}
if (DRM_COPY_FROM_USER(p->chunks[i].kdata,
p->chunks[i].user_ptr, size)) {
return -EFAULT;
}
} else {
p->chunks[i].kpage[0] = kmalloc(PAGE_SIZE, GFP_KERNEL);
p->chunks[i].kpage[1] = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (p->chunks[i].kpage[0] == NULL || p->chunks[i].kpage[1] == NULL) {
kfree(p->chunks[i].kpage[0]);
kfree(p->chunks[i].kpage[1]);
return -ENOMEM;
}
p->chunks[i].kpage_idx[0] = -1;
p->chunks[i].kpage_idx[1] = -1;
p->chunks[i].last_copied_page = -1;
p->chunks[i].last_page_index = ((p->chunks[i].length_dw * 4) - 1) / PAGE_SIZE;
}
}
if (p->chunks[p->chunk_ib_idx].length_dw > (16 * 1024)) {
DRM_ERROR("cs IB too big: %d\n",
p->chunks[p->chunk_ib_idx].length_dw);
return -EINVAL;
}
return 0;
}
/**
* cs_parser_fini() - clean parser states
* @parser: parser structure holding parsing context.
* @error: error number
*
* If error is set than unvalidate buffer, otherwise just free memory
* used by parsing context.
**/
static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error)
{
unsigned i;
if (error) {
radeon_bo_list_unvalidate(&parser->validated,
parser->ib->fence);
} else {
radeon_bo_list_unreserve(&parser->validated);
}
for (i = 0; i < parser->nrelocs; i++) {
if (parser->relocs[i].gobj) {
mutex_lock(&parser->rdev->ddev->struct_mutex);
drm_gem_object_unreference(parser->relocs[i].gobj);
mutex_unlock(&parser->rdev->ddev->struct_mutex);
}
}
kfree(parser->track);
kfree(parser->relocs);
kfree(parser->relocs_ptr);
for (i = 0; i < parser->nchunks; i++) {
kfree(parser->chunks[i].kdata);
kfree(parser->chunks[i].kpage[0]);
kfree(parser->chunks[i].kpage[1]);
}
kfree(parser->chunks);
kfree(parser->chunks_array);
radeon_ib_free(parser->rdev, &parser->ib);
}
int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
{
struct radeon_device *rdev = dev->dev_private;
struct radeon_cs_parser parser;
struct radeon_cs_chunk *ib_chunk;
int r;
mutex_lock(&rdev->cs_mutex);
if (rdev->gpu_lockup) {
mutex_unlock(&rdev->cs_mutex);
return -EINVAL;
}
/* initialize parser */
memset(&parser, 0, sizeof(struct radeon_cs_parser));
parser.filp = filp;
parser.rdev = rdev;
parser.dev = rdev->dev;
r = radeon_cs_parser_init(&parser, data);
if (r) {
DRM_ERROR("Failed to initialize parser !\n");
radeon_cs_parser_fini(&parser, r);
mutex_unlock(&rdev->cs_mutex);
return r;
}
r = radeon_ib_get(rdev, &parser.ib);
if (r) {
DRM_ERROR("Failed to get ib !\n");
radeon_cs_parser_fini(&parser, r);
mutex_unlock(&rdev->cs_mutex);
return r;
}
r = radeon_cs_parser_relocs(&parser);
if (r) {
DRM_ERROR("Failed to parse relocation !\n");
radeon_cs_parser_fini(&parser, r);
mutex_unlock(&rdev->cs_mutex);
return r;
}
/* Copy the packet into the IB, the parser will read from the
* input memory (cached) and write to the IB (which can be
* uncached). */
ib_chunk = &parser.chunks[parser.chunk_ib_idx];
parser.ib->length_dw = ib_chunk->length_dw;
r = radeon_cs_parse(&parser);
if (r || parser.parser_error) {
DRM_ERROR("Invalid command stream !\n");
radeon_cs_parser_fini(&parser, r);
mutex_unlock(&rdev->cs_mutex);
return r;
}
r = radeon_cs_finish_pages(&parser);
if (r) {
DRM_ERROR("Invalid command stream !\n");
radeon_cs_parser_fini(&parser, r);
mutex_unlock(&rdev->cs_mutex);
return r;
}
r = radeon_ib_schedule(rdev, parser.ib);
if (r) {
DRM_ERROR("Faild to schedule IB !\n");
}
radeon_cs_parser_fini(&parser, r);
mutex_unlock(&rdev->cs_mutex);
return r;
}
int radeon_cs_finish_pages(struct radeon_cs_parser *p)
{
struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];
int i;
int size = PAGE_SIZE;
for (i = ibc->last_copied_page + 1; i <= ibc->last_page_index; i++) {
if (i == ibc->last_page_index) {
size = (ibc->length_dw * 4) % PAGE_SIZE;
if (size == 0)
size = PAGE_SIZE;
}
if (DRM_COPY_FROM_USER(p->ib->ptr + (i * (PAGE_SIZE/4)),
ibc->user_ptr + (i * PAGE_SIZE),
size))
return -EFAULT;
}
return 0;
}
int radeon_cs_update_pages(struct radeon_cs_parser *p, int pg_idx)
{
int new_page;
struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];
int i;
int size = PAGE_SIZE;
for (i = ibc->last_copied_page + 1; i < pg_idx; i++) {
if (DRM_COPY_FROM_USER(p->ib->ptr + (i * (PAGE_SIZE/4)),
ibc->user_ptr + (i * PAGE_SIZE),
PAGE_SIZE)) {
p->parser_error = -EFAULT;
return 0;
}
}
new_page = ibc->kpage_idx[0] < ibc->kpage_idx[1] ? 0 : 1;
if (pg_idx == ibc->last_page_index) {
size = (ibc->length_dw * 4) % PAGE_SIZE;
if (size == 0)
size = PAGE_SIZE;
}
if (DRM_COPY_FROM_USER(ibc->kpage[new_page],
ibc->user_ptr + (pg_idx * PAGE_SIZE),
size)) {
p->parser_error = -EFAULT;
return 0;
}
/* copy to IB here */
memcpy((void *)(p->ib->ptr+(pg_idx*(PAGE_SIZE/4))), ibc->kpage[new_page], size);
ibc->last_copied_page = pg_idx;
ibc->kpage_idx[new_page] = pg_idx;
return new_page;
}