[Nouveau] [PATCH] drm/nouveau: fix a use-after-free in nouveau_gem_prime_import_sg_table()

2022-08-04 Thread Jianglei Nie
nouveau_bo_init() is backed by ttm_bo_init() and ferries its return code
back to the caller. On failures, ttm will call nouveau_bo_del_ttm() and
free the memory.Thus, when nouveau_bo_init() returns an error, the gem
object has already been released. Then the call to nouveau_bo_ref() will
use the freed "nvbo->bo" and lead to a use-after-free bug.

We should delete the call to nouveau_bo_ref() to avoid the use-after-free.

Signed-off-by: Jianglei Nie 
---
 drivers/gpu/drm/nouveau/nouveau_prime.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c 
b/drivers/gpu/drm/nouveau/nouveau_prime.c
index 347488685f74..9608121e49b7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_prime.c
+++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
@@ -71,7 +71,6 @@ struct drm_gem_object 
*nouveau_gem_prime_import_sg_table(struct drm_device *dev,
ret = nouveau_bo_init(nvbo, size, align, NOUVEAU_GEM_DOMAIN_GART,
  sg, robj);
if (ret) {
-   nouveau_bo_ref(NULL, );
obj = ERR_PTR(ret);
goto unlock;
}
-- 
2.25.1



Re: [Nouveau] [PATCH] drm/nouveau: fix a use-after-free in nouveau_gem_prime_import_sg_table()

2022-07-07 Thread Lyude Paul
Reviewed-by: Lyude Paul 

Will push to the appropriate branch in a moment

On Tue, 2022-07-05 at 21:25 +0800, Jianglei Nie wrote:
> nouveau_bo_init() is backed by ttm_bo_init() and ferries its return code
> back to the caller. On failures, ttm will call nouveau_bo_del_ttm() and
> free the memory.Thus, when nouveau_bo_init() returns an error, the gem
> object has already been released. Then the call to nouveau_bo_ref() will
> use the freed "nvbo->bo" and lead to a use-after-free bug.
> 
> We should delete the call to nouveau_bo_ref() to avoid the use-after-free.
> 
> Signed-off-by: Jianglei Nie 
> ---
>  drivers/gpu/drm/nouveau/nouveau_prime.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c
> b/drivers/gpu/drm/nouveau/nouveau_prime.c
> index 347488685f74..9608121e49b7 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_prime.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
> @@ -71,7 +71,6 @@ struct drm_gem_object
> *nouveau_gem_prime_import_sg_table(struct drm_device *dev,
> ret = nouveau_bo_init(nvbo, size, align, NOUVEAU_GEM_DOMAIN_GART,
>   sg, robj);
> if (ret) {
> -   nouveau_bo_ref(NULL, );
> obj = ERR_PTR(ret);
> goto unlock;
> }

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat