On Wed Jan 28, 2026 at 4:58 PM JST, Alexandre Courbot wrote:
> On Tue Jan 27, 2026 at 5:23 AM JST, Joel Fernandes wrote:
>> Use checked_add() and checked_mul() when computing offsets from
>> firmware-provided values in new_fwsec().
>>
>> Without checked arithmetic, corrupt firmware could cause integer overflow.
>> The
>> danger is not just wrapping to a huge value, but potentially wrapping to a
>> small plausible offset that passes validation yet accesses entirely wrong
>> data,
>> causing silent corruption or security issues.
>>
>> Reviewed-by: Zhi Wang <[email protected]>
>> Signed-off-by: Joel Fernandes <[email protected]>
>> ---
>> drivers/gpu/nova-core/firmware/fwsec.rs | 60 ++++++++++++++-----------
>> 1 file changed, 35 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/gpu/nova-core/firmware/fwsec.rs
>> b/drivers/gpu/nova-core/firmware/fwsec.rs
>> index a8ec08a500ac..71541b1f07d7 100644
>> --- a/drivers/gpu/nova-core/firmware/fwsec.rs
>> +++ b/drivers/gpu/nova-core/firmware/fwsec.rs
>> @@ -46,10 +46,7 @@
>> Signed,
>> Unsigned, //
>> },
>> - num::{
>> - FromSafeCast,
>> - IntoSafeCast, //
>> - },
>> + num::FromSafeCast,
>> vbios::Vbios,
>> };
>>
>> @@ -267,7 +264,12 @@ fn new_fwsec(dev: &Device<device::Bound>, bios: &Vbios,
>> cmd: FwsecCommand) -> Re
>> let ucode = bios.fwsec_image().ucode(&desc)?;
>> let mut dma_object = DmaObject::from_data(dev, ucode)?;
>>
>> - let hdr_offset = usize::from_safe_cast(desc.imem_load_size() +
>> desc.interface_offset());
>> + // Compute hdr_offset = imem_load_size + interface_offset.
>> + let hdr_offset = desc
>> + .imem_load_size()
>> + .checked_add(desc.interface_offset())
>> + .map(usize::from_safe_cast)
>> + .ok_or(EINVAL)?;
>> // SAFETY: we have exclusive access to `dma_object`.
>
> Missing empty line before the SAFETY comment (also in other places).
>
> I will fix when applying, no need to resend.
I also got this clippy warning when building:
warning: unsafe block missing a safety comment
--> ../drivers/gpu/nova-core/firmware/fwsec.rs:303:17
|
303 | unsafe { transmute_mut(&mut dma_object,
dmem_mapper_offset) }?;
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider adding a safety comment on the
preceding line
= help: for further information visit
https://rust-lang.github.io/rust-clippy/master/index.html#undocumented_unsafe_blocks
= note: requested on the command line with `-W
clippy::undocumented-unsafe-blocks`
warning: unsafe block missing a safety comment
--> ../drivers/gpu/nova-core/firmware/fwsec.rs:319:17
|
319 | unsafe { transmute_mut(&mut dma_object,
frts_cmd_offset) }?;
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider adding a safety comment on the
preceding line
= help: for further information visit
https://rust-lang.github.io/rust-clippy/master/index.html#undocumented_unsafe_blocks
warning: 2 warnings emitted
Since the `unsafe` keyword has moved to a new line, its SAFETY comment needed
to be moved right above it, despite it still being part of the same statement.
I'll fix this as well.
