[PATCH] nouveau/gsp: fix UBSAN array bounds warning in PACKED_REGISTRY_TABLE

[PATCH] nouveau/gsp: fix UBSAN array bounds warning in PACKED_REGISTRY_TABLE

[Timur Tabi]

Change PACKED_REGISTRY_TABLE so that its last member is a variable-length
array instead of a zero-length array.  UBSAN treats zero-length arrays
literally and warns if they are dereferenced.  Changing the "[0]" to "[]"
tells the compiler that the array is variable-length.

This fixes the following warning in function r535_gsp_rpc_set_registry
when CONFIG_UBSAN_BOUNDS is enabled:

UBSAN: array-index-out-of-bounds in drivers/gpu/drm/nouveau/nvkm/
subdev/gsp/r535.c:1066:33
index 2 is out of range for type 'PACKED_REGISTRY_ENTRY [*]'

Fixes: b5bad8c16b9b ("nouveau/gsp: move to 535.113.01")
Signed-off-by: Timur Tabi <ttabi@nvidia.com>
---
 .../include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h        | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h b/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h
index 754c6af42f30..1d236c68fa30 100644
--- a/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h
+++ b/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h
@@ -38,7 +38,7 @@ typedef struct PACKED_REGISTRY_TABLE
 {
     NvU32                   size;
     NvU32                   numEntries;
-    PACKED_REGISTRY_ENTRY   entries[0];
+    PACKED_REGISTRY_ENTRY   entries[];
 } PACKED_REGISTRY_TABLE;
 
 #endif
-- 
2.34.1

Re: [Nouveau] [PATCH] nouveau/gsp: fix UBSAN array bounds warning in PACKED_REGISTRY_TABLE

[Danilo Krummrich]

On 11/8/23 00:47, Timur Tabi wrote:
> Change PACKED_REGISTRY_TABLE so that its last member is a variable-length
> array instead of a zero-length array.  UBSAN treats zero-length arrays
> literally and warns if they are dereferenced.  Changing the "[0]" to "[]"
> tells the compiler that the array is variable-length.

Do you also intend to fix this upstream? (And with upstream I mean the
open-gpu-kernel-modules in this case.)

> 
> This fixes the following warning in function r535_gsp_rpc_set_registry
> when CONFIG_UBSAN_BOUNDS is enabled:
> 
> UBSAN: array-index-out-of-bounds in drivers/gpu/drm/nouveau/nvkm/
> subdev/gsp/r535.c:1066:33
> index 2 is out of range for type 'PACKED_REGISTRY_ENTRY [*]'
> 
> Fixes: b5bad8c16b9b ("nouveau/gsp: move to 535.113.01")
> Signed-off-by: Timur Tabi <ttabi@nvidia.com>
> ---
>   .../include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h        | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h b/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h
> index 754c6af42f30..1d236c68fa30 100644
> --- a/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h
> +++ b/drivers/gpu/drm/nouveau/include/nvrm/535.113.01/nvidia/generated/g_os_nvoc.h
> @@ -38,7 +38,7 @@ typedef struct PACKED_REGISTRY_TABLE
>   {
>       NvU32                   size;
>       NvU32                   numEntries;
> -    PACKED_REGISTRY_ENTRY   entries[0];
> +    PACKED_REGISTRY_ENTRY   entries[];
>   } PACKED_REGISTRY_TABLE;
>   
>   #endif

Re: [Nouveau] [PATCH] nouveau/gsp: fix UBSAN array bounds warning in PACKED_REGISTRY_TABLE

[Timur Tabi]

On Wed, 2023-11-08 at 00:52 +0100, Danilo Krummrich wrote:
> On 11/8/23 00:47, Timur Tabi wrote:
> > Change PACKED_REGISTRY_TABLE so that its last member is a variable-
> > length
> > array instead of a zero-length array.  UBSAN treats zero-length arrays
> > literally and warns if they are dereferenced.  Changing the "[0]" to
> > "[]"
> > tells the compiler that the array is variable-length.
> 
> Do you also intend to fix this upstream? (And with upstream I mean the
> open-gpu-kernel-modules in this case.)

Hmmm, I hadn't thought about that.  I would need to repro (or see a repro)
with OpenRM to justify changing it.  OpenRM doesn't build the registry the
way Nouveau does.