From: Dmitry Osipenko dmitry.osipenko@collabora.com
commit ee9adb7a45516cfa536ca92253d7ae59d56db9e4 upstream.
drm_gem_shmem_mmap() doesn't own reference in error code path, resulting in the dma-buf shmem GEM object getting prematurely freed leading to a later use-after-free.
Fixes: f49a51bfdc8e ("drm/shme-helpers: Fix dma_buf_mmap forwarding bug") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Osipenko dmitry.osipenko@collabora.com Reviewed-by: Rob Clark robdclark@gmail.com Link: https://patchwork.freedesktop.org/patch/msgid/20230108211311.3950107-1-dmitr... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/drm_gem_shmem_helper.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -614,11 +614,14 @@ int drm_gem_shmem_mmap(struct drm_gem_ob int ret;
if (obj->import_attach) { - /* Drop the reference drm_gem_mmap_obj() acquired.*/ - drm_gem_object_put(obj); vma->vm_private_data = NULL; + ret = dma_buf_mmap(obj->dma_buf, vma, 0); + + /* Drop the reference drm_gem_mmap_obj() acquired.*/ + if (!ret) + drm_gem_object_put(obj);
- return dma_buf_mmap(obj->dma_buf, vma, 0); + return ret; }
shmem = to_drm_gem_shmem_obj(obj);