From: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Reviewed-by: Rob Clark <robdclark@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20230108211311.3950107-1-dmitry.osipenko@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
