gpu: nova-core: use checked arithmetic in RISC-V firmware parsing

Use checked_add() when computing offsets from firmware-provided values
in the RISC-V firmware parsing code. These values come from the BinHdr
structure parsed from the firmware file header.

Reviewed-by: Zhi Wang <zhiw@nvidia.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260126202305.2526618-6-joelagnelf@nvidia.com
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

diff --git a/drivers/gpu/nova-core/firmware/riscv.rs b/drivers/gpu/nova-core/firmware/riscv.rs
index 4bdd89bd07578abd6e51033f81f5f0ec43db9b79..14aad2f0ee8af92804e4628b5d52271743dd0396 100644 (file)
--- a/drivers/gpu/nova-core/firmware/riscv.rs
+++ b/drivers/gpu/nova-core/firmware/riscv.rs
@@ -45,10 +45,11 @@ impl RmRiscvUCodeDesc {
     /// Fails if the header pointed at by `bin_fw` is not within the bounds of the firmware image.
     fn new(bin_fw: &BinFirmware<'_>) -> Result<Self> {
         let offset = usize::from_safe_cast(bin_fw.hdr.header_offset);
+        let end = offset.checked_add(size_of::<Self>()).ok_or(EINVAL)?;
 
         bin_fw
             .fw
-            .get(offset..offset + size_of::<Self>())
+            .get(offset..end)
             .and_then(Self::from_bytes_copy)
             .ok_or(EINVAL)
     }
@@ -78,8 +79,9 @@ impl RiscvFirmware {
         let ucode = {
             let start = usize::from_safe_cast(bin_fw.hdr.data_offset);
             let len = usize::from_safe_cast(bin_fw.hdr.data_size);
+            let end = start.checked_add(len).ok_or(EINVAL)?;
 
-            DmaObject::from_data(dev, fw.data().get(start..start + len).ok_or(EINVAL)?)?
+            DmaObject::from_data(dev, fw.data().get(start..end).ok_or(EINVAL)?)?
         };
 
         Ok(Self {