drm/nouveau/gsp: Fix potential integer overflow on integer shifts

[PATCH][next] drm/nouveau/gsp: Fix potential integer overflow on integer shifts

Posted by Colin Ian King 6 months, 3 weeks ago

The left shift int 32 bit integer constants 1 is evaluated using 32 bit
arithmetic and then assigned to a 64 bit unsigned integer. In the case
where the shift is 32 or more this can lead to an overflow. Avoid this
by shifting using the BIT_ULL macro instead.

Fixes: 6c3ac7bcfcff ("drm/nouveau/gsp: support deeper page tables in COPY_SERVER_RESERVED_PDES")

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/vmm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/vmm.c b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/vmm.c
index 52f2e5f14517..f25ea610cd99 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/vmm.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/vmm.c
@@ -121,7 +121,7 @@ r535_mmu_vaspace_new(struct nvkm_vmm *vmm, u32 handle, bool external)
 			page_shift -= desc->bits;
 
 			ctrl->levels[i].physAddress = pd->pt[0]->addr;
-			ctrl->levels[i].size = (1 << desc->bits) * desc->size;
+			ctrl->levels[i].size = BIT_ULL(desc->bits) * desc->size;
 			ctrl->levels[i].aperture = 1;
 			ctrl->levels[i].pageShift = page_shift;
 
-- 
2.49.0

Re: [PATCH][next] drm/nouveau/gsp: Fix potential integer overflow on integer shifts

Posted by Danilo Krummrich 6 months ago

On 5/22/25 3:15 PM, Colin Ian King wrote:
> The left shift int 32 bit integer constants 1 is evaluated using 32 bit
> arithmetic and then assigned to a 64 bit unsigned integer. In the case
> where the shift is 32 or more this can lead to an overflow. Avoid this
> by shifting using the BIT_ULL macro instead.
> 
> Fixes: 6c3ac7bcfcff ("drm/nouveau/gsp: support deeper page tables in COPY_SERVER_RESERVED_PDES")
> 
> Signed-off-by: Colin Ian King <colin.i.king@gmail.com>

Applied to drm-misc-fixes, thanks!