If radeon_cs_parser_init() fails, radeon_cs_ioctl() calls
radeon_cs_parser_fini() with the non-zero error value. The latter dereferenced
parser->ib which hasn't been initialized yet -> boom. Add a test for parser->ib
being non-NULL before dereferencing it.
Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
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=95d63e408cc88b6934bec84a0b1ef94dfe8bee7bhttp://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>
The locking & protection of radeon object was somewhat messy.
This patch completely rework it to now use ttm reserve as a
protection for the radeon object structure member. It also
shrink down the various radeon object structure by removing
field which were redondant with the ttm information. Last it
converts few simple functions to inline which should with
performances.
airlied: rebase on top of r600 and other changes.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Thanks to Michel for pointing this out to me, this is
why I need to get more sleep, over complicate this a bit.
Signed-off-by: Dave Airlie <airlied@redhat.com>
This avoids needing to do a kmalloc > PAGE_SIZE for the main
indirect buffer chunk, it adds an accessor for all reads from
the chunk and caches a single page at a time for subsequent
reads.
changes since v1:
Use a two page pool which should be the most common case
a single packet spanning > PAGE_SIZE will be hit, but I'm
having trouble seeing anywhere we currently generate anything like that.
hopefully proper short page copying at end
added parser_error flag to set deep errors instead of having to test
every ib value fetch.
fixed bug in patch that went to list.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Fixes leak hidden in commit 9f022ddfb2
('drm/radeon/kms: convert r4xx to new init path').
Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
Add kernel modesetting support to radeon driver, use the ttm memory
manager to manage memory and DRM/GEM to provide userspace API.
In order to avoid backward compatibility issue and to allow clean
design and code the radeon kernel modesetting use different code path
than old radeon/drm driver.
When kernel modesetting is enabled the IOCTL of radeon/drm
driver are considered as invalid and an error message is printed
in the log and they return failure.
KMS enabled userspace will use new API to talk with the radeon/drm
driver. The new API provide functions to create/destroy/share/mmap
buffer object which are then managed by the kernel memory manager
(here TTM). In order to submit command to the GPU the userspace
provide a buffer holding the command stream, along this buffer
userspace have to provide a list of buffer object used by the
command stream. The kernel radeon driver will then place buffer
in GPU accessible memory and will update command stream to reflect
the position of the different buffers.
The kernel will also perform security check on command stream
provided by the user, we want to catch and forbid any illegal use
of the GPU such as DMA into random system memory or into memory
not owned by the process supplying the command stream. This part
of the code is still incomplete and this why we propose that patch
as a staging driver addition, future security might forbid current
experimental userspace to run.
This code support the following hardware : R1XX,R2XX,R3XX,R4XX,R5XX
(radeon up to X1950). Works is underway to provide support for R6XX,
R7XX and newer hardware (radeon from HD2XXX to HD4XXX).
Authors:
Jerome Glisse <jglisse@redhat.com>
Dave Airlie <airlied@redhat.com>
Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
