On Mon, Jul 20, 2026 at 03:44:35PM +0200, Osama Abdelkader wrote:
> panthor_init_cs_iface() and panthor_init_csg_iface() validate firmware
> control interface offsets with 32-bit arithmetic and the size of the host
> wrapper structures. The offsets are derived from firmware-provided strides,
> so the arithmetic can wrap before the bounds check, and the host wrapper
> size is not the size of the firmware control interface being mapped.
How can the offsets wrap with the firmware-provided strides? It's not like
the firmware provides arbitrarily large strides.
>
> Use 64-bit arithmetic for the computed offsets and validate against the
> actual firmware control interface structure sizes with subtraction-based
> bounds checks. Also validate that the shared section is large enough for
> the global control interface before using it.
>
> Fixes: 2718d91816ee ("drm/panthor: Add the FW logical block")
> Cc: [email protected]
> Signed-off-by: Osama Abdelkader <[email protected]>
> ---
> drivers/gpu/drm/panthor/panthor_fw.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c
> b/drivers/gpu/drm/panthor/panthor_fw.c
> index eee2bc7e8541..e2fcbd639c3c 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -897,15 +897,16 @@ static int panthor_init_cs_iface(struct panthor_device
> *ptdev,
> struct panthor_fw_csg_iface *csg_iface =
> panthor_fw_get_csg_iface(ptdev, csg_idx);
> struct panthor_fw_cs_iface *cs_iface =
> &ptdev->fw->iface.streams[csg_idx][cs_idx];
> u64 shared_section_sz =
> panthor_kernel_bo_size(ptdev->fw->shared_section->mem);
> - u32 iface_offset = CSF_GROUP_CONTROL_OFFSET +
> - (csg_idx * glb_iface->control->group_stride) +
> + u64 iface_offset = CSF_GROUP_CONTROL_OFFSET +
> + ((u64)csg_idx * glb_iface->control->group_stride) +
> CSF_STREAM_CONTROL_OFFSET +
> - (cs_idx * csg_iface->control->stream_stride);
> + ((u64)cs_idx * csg_iface->control->stream_stride);
> struct panthor_fw_cs_iface *first_cs_iface =
> panthor_fw_get_cs_iface(ptdev, 0, 0);
>
> - if (iface_offset + sizeof(*cs_iface) >= shared_section_sz)
> + if (iface_offset > shared_section_sz ||
> + sizeof(*cs_iface->control) > shared_section_sz - iface_offset)
> return -EINVAL;
>
> spin_lock_init(&cs_iface->lock);
> cs_iface->control = ptdev->fw->shared_section->mem->kmap + iface_offset;
> @@ -955,11 +956,13 @@ static int panthor_init_csg_iface(struct panthor_device
> *ptdev,
> struct panthor_fw_global_iface *glb_iface =
> panthor_fw_get_glb_iface(ptdev);
> struct panthor_fw_csg_iface *csg_iface =
> &ptdev->fw->iface.groups[csg_idx];
> u64 shared_section_sz =
> panthor_kernel_bo_size(ptdev->fw->shared_section->mem);
> - u32 iface_offset = CSF_GROUP_CONTROL_OFFSET + (csg_idx *
> glb_iface->control->group_stride);
> + u64 iface_offset = CSF_GROUP_CONTROL_OFFSET +
> + ((u64)csg_idx * glb_iface->control->group_stride);
> unsigned int i;
>
> - if (iface_offset + sizeof(*csg_iface) >= shared_section_sz)
> + if (iface_offset > shared_section_sz ||
> + sizeof(*csg_iface->control) > shared_section_sz - iface_offset)
> return -EINVAL;
>
> spin_lock_init(&csg_iface->lock);
> csg_iface->control = ptdev->fw->shared_section->mem->kmap +
> iface_offset;
> @@ -1011,12 +1014,16 @@ static u32 panthor_get_instr_features(struct
> panthor_device *ptdev)
> static int panthor_fw_init_ifaces(struct panthor_device *ptdev)
> {
> struct panthor_fw_global_iface *glb_iface = &ptdev->fw->iface.global;
> + u64 shared_section_sz =
> panthor_kernel_bo_size(ptdev->fw->shared_section->mem);
> unsigned int i;
>
> if (!ptdev->fw->shared_section->mem->kmap)
> return -EINVAL;
>
> + if (sizeof(*glb_iface->control) > shared_section_sz)
> + return -EINVAL;
> +
> spin_lock_init(&glb_iface->lock);
> glb_iface->control = ptdev->fw->shared_section->mem->kmap;
>
> if (!glb_iface->control->version) {
> --
> 2.43.0
>
I'm OK with the general content of the patch, so:
Reviewed-by: Liviu Dudau <[email protected]>
Best regards,
Liviu
--
====================
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| fix the world, |
| but they're not |
| giving me the |
\ source code! /
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