Thierry Reding
2021-May-17 08:56 UTC
[Nouveau] [PATCH] nouveau/gem: fix user-after-free in nouveau_gem_new
On Tue, May 11, 2021 at 06:35:53PM +0200, Karol Herbst wrote:> If ttm_bo_init fails it will already call ttm_bo_put, so we don't have to > do it through nouveau_bo_ref. > > =================================================================> BUG: KFENCE: use-after-free write in ttm_bo_put+0x11/0x40 [ttm] > > Use-after-free write at 0x000000004dc4663c (in kfence-#44): > ttm_bo_put+0x11/0x40 [ttm] > nouveau_gem_new+0xc1/0xf0 [nouveau] > nouveau_gem_ioctl_new+0x53/0xf0 [nouveau] > drm_ioctl_kernel+0xb2/0x100 [drm] > drm_ioctl+0x215/0x390 [drm] > nouveau_drm_ioctl+0x55/0xa0 [nouveau] > __x64_sys_ioctl+0x83/0xb0 > do_syscall_64+0x33/0x40 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > kfence-#44 [0x00000000c0593b31-0x000000002e74122b, size=792, cache=kmalloc-1k] allocated by task 2657: > nouveau_bo_alloc+0x63/0x4c0 [nouveau] > nouveau_gem_new+0x38/0xf0 [nouveau] > nouveau_gem_ioctl_new+0x53/0xf0 [nouveau] > drm_ioctl_kernel+0xb2/0x100 [drm] > drm_ioctl+0x215/0x390 [drm] > nouveau_drm_ioctl+0x55/0xa0 [nouveau] > __x64_sys_ioctl+0x83/0xb0 > do_syscall_64+0x33/0x40 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > freed by task 2657: > ttm_bo_release+0x1cc/0x300 [ttm] > ttm_bo_init_reserved+0x2ec/0x300 [ttm] > ttm_bo_init+0x5e/0xd0 [ttm] > nouveau_bo_init+0xaf/0xc0 [nouveau] > nouveau_gem_new+0x7f/0xf0 [nouveau] > nouveau_gem_ioctl_new+0x53/0xf0 [nouveau] > drm_ioctl_kernel+0xb2/0x100 [drm] > drm_ioctl+0x215/0x390 [drm] > nouveau_drm_ioctl+0x55/0xa0 [nouveau] > __x64_sys_ioctl+0x83/0xb0 > do_syscall_64+0x33/0x40 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > Fixes: 019cbd4a4feb3 "drm/nouveau: Initialize GEM object before TTM object" > Cc: Thierry Reding <treding at nvidia.com> > Signed-off-by: Karol Herbst <kherbst at redhat.com> > --- > drivers/gpu/drm/nouveau/nouveau_gem.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c > index c88cbb85f101..1165ff990fb5 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c > @@ -212,7 +212,6 @@ nouveau_gem_new(struct nouveau_cli *cli, u64 size, int align, uint32_t domain, > > ret = nouveau_bo_init(nvbo, size, align, domain, NULL, NULL); > if (ret) { > - nouveau_bo_ref(NULL, &nvbo); > return ret; > }Looking at the surrounding code, I wonder if I just managed to jumble the cleanup paths for drm_gem_object_init() and nouveau_bo_init(). If drm_gem_object_init() fails, I don't think it's necessary (though it also doesn't look harmful) to call drm_gem_object_release(). However, if nouveau_bo_init() fails, then I think we'd still need to call drm_gem_object_release(), to make sure to undo the effects of drm_gem_object_init(). So I wonder if we need something like this instead: --- >8 --- diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c index c88cbb85f101..9b6055116f30 100644 --- a/drivers/gpu/drm/nouveau/nouveau_gem.c +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c @@ -205,14 +205,13 @@ nouveau_gem_new(struct nouveau_cli *cli, u64 size, int align, uint32_t domain, * to the caller, instead of a normal nouveau_bo ttm reference. */ ret = drm_gem_object_init(drm->dev, &nvbo->bo.base, size); if (ret) { - drm_gem_object_release(&nvbo->bo.base); kfree(nvbo); return ret; } ret = nouveau_bo_init(nvbo, size, align, domain, NULL, NULL); if (ret) { - nouveau_bo_ref(NULL, &nvbo); + drm_gem_object_release(&nvbo->bo.base); return ret; } --- >8 --- Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: not available URL: <https://lists.freedesktop.org/archives/nouveau/attachments/20210517/52999e2d/attachment.sig>
Thierry Reding
2021-May-17 09:19 UTC
[Nouveau] [PATCH] nouveau/gem: fix user-after-free in nouveau_gem_new
On Mon, May 17, 2021 at 10:56:29AM +0200, Thierry Reding wrote:> On Tue, May 11, 2021 at 06:35:53PM +0200, Karol Herbst wrote: > > If ttm_bo_init fails it will already call ttm_bo_put, so we don't have to > > do it through nouveau_bo_ref. > > > > =================================================================> > BUG: KFENCE: use-after-free write in ttm_bo_put+0x11/0x40 [ttm] > > > > Use-after-free write at 0x000000004dc4663c (in kfence-#44): > > ttm_bo_put+0x11/0x40 [ttm] > > nouveau_gem_new+0xc1/0xf0 [nouveau] > > nouveau_gem_ioctl_new+0x53/0xf0 [nouveau] > > drm_ioctl_kernel+0xb2/0x100 [drm] > > drm_ioctl+0x215/0x390 [drm] > > nouveau_drm_ioctl+0x55/0xa0 [nouveau] > > __x64_sys_ioctl+0x83/0xb0 > > do_syscall_64+0x33/0x40 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > > > kfence-#44 [0x00000000c0593b31-0x000000002e74122b, size=792, cache=kmalloc-1k] allocated by task 2657: > > nouveau_bo_alloc+0x63/0x4c0 [nouveau] > > nouveau_gem_new+0x38/0xf0 [nouveau] > > nouveau_gem_ioctl_new+0x53/0xf0 [nouveau] > > drm_ioctl_kernel+0xb2/0x100 [drm] > > drm_ioctl+0x215/0x390 [drm] > > nouveau_drm_ioctl+0x55/0xa0 [nouveau] > > __x64_sys_ioctl+0x83/0xb0 > > do_syscall_64+0x33/0x40 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > > > freed by task 2657: > > ttm_bo_release+0x1cc/0x300 [ttm] > > ttm_bo_init_reserved+0x2ec/0x300 [ttm] > > ttm_bo_init+0x5e/0xd0 [ttm] > > nouveau_bo_init+0xaf/0xc0 [nouveau] > > nouveau_gem_new+0x7f/0xf0 [nouveau] > > nouveau_gem_ioctl_new+0x53/0xf0 [nouveau] > > drm_ioctl_kernel+0xb2/0x100 [drm] > > drm_ioctl+0x215/0x390 [drm] > > nouveau_drm_ioctl+0x55/0xa0 [nouveau] > > __x64_sys_ioctl+0x83/0xb0 > > do_syscall_64+0x33/0x40 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > > > Fixes: 019cbd4a4feb3 "drm/nouveau: Initialize GEM object before TTM object" > > Cc: Thierry Reding <treding at nvidia.com> > > Signed-off-by: Karol Herbst <kherbst at redhat.com> > > --- > > drivers/gpu/drm/nouveau/nouveau_gem.c | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c > > index c88cbb85f101..1165ff990fb5 100644 > > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c > > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c > > @@ -212,7 +212,6 @@ nouveau_gem_new(struct nouveau_cli *cli, u64 size, int align, uint32_t domain, > > > > ret = nouveau_bo_init(nvbo, size, align, domain, NULL, NULL); > > if (ret) { > > - nouveau_bo_ref(NULL, &nvbo); > > return ret; > > } > > Looking at the surrounding code, I wonder if I just managed to jumble > the cleanup paths for drm_gem_object_init() and nouveau_bo_init(). If > drm_gem_object_init() fails, I don't think it's necessary (though it > also doesn't look harmful) to call drm_gem_object_release(). > > However, if nouveau_bo_init() fails, then I think we'd still need to > call drm_gem_object_release(), to make sure to undo the effects of > drm_gem_object_init(). > > So I wonder if we need something like this instead: > > --- >8 --- > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c > index c88cbb85f101..9b6055116f30 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c > @@ -205,14 +205,13 @@ nouveau_gem_new(struct nouveau_cli *cli, u64 size, int align, uint32_t domain, > * to the caller, instead of a normal nouveau_bo ttm reference. */ > ret = drm_gem_object_init(drm->dev, &nvbo->bo.base, size); > if (ret) { > - drm_gem_object_release(&nvbo->bo.base); > kfree(nvbo); > return ret; > } > > ret = nouveau_bo_init(nvbo, size, align, domain, NULL, NULL); > if (ret) { > - nouveau_bo_ref(NULL, &nvbo); > + drm_gem_object_release(&nvbo->bo.base); > return ret; > } > > --- >8 --- > > ThierryAdding Jeremy for visibility. Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: not available URL: <https://lists.freedesktop.org/archives/nouveau/attachments/20210517/8b85b94e/attachment-0001.sig>