drm/etnaviv: limit submit sizes

commit 6dfa2fab8ddd46faa771a102672176bee7a065de upstream.

Currently we allow rediculous amounts of kernel memory being allocated
via the etnaviv GEM_SUBMIT ioctl, which is a pretty easy DoS vector. Put
some reasonable limits in to fix this.

The commandstream size is limited to 64KB, which was already a soft limit
on older kernels after which the kernel only took submits on a best effort
base, so there is no userspace that tries to submit commandstreams larger
than this. Even if the whole commandstream is a single incrementing address
load, the size limit also limits the number of potential relocs and
referenced buffers to slightly under 64K, so use the same limit for those
arguments. The performance monitoring infrastructure currently supports
less than 50 performance counter signals, so limiting them to 128 on a
single submit seems like a reasonably future-proof number for now. This
number can be bumped if needed without breaking the interface.

Cc: stable@vger.kernel.org
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
index 983e67f19e4508b5023cb5efba221981f4a9b4b0..2b57a581b29e29ea0eb3137c8c55bc225aa3c10b 100644 (file)
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
@@ -444,6 +444,12 @@ int etnaviv_ioctl_gem_submit(struct drm_device *dev, void *data,
                return -EINVAL;
        }
 
+       if (args->stream_size > SZ_64K || args->nr_relocs > SZ_64K ||
+           args->nr_bos > SZ_64K || args->nr_pmrs > 128) {
+               DRM_ERROR("submit arguments out of size limits\n");
+               return -EINVAL;
+       }
+
        /*
         * Copy the command submission and bo array to kernel space in
         * one go, and do this outside of any locks.