[PATCH v1 3/5] gpu: nova-core: use checked arithmetic in frombytes_at helper

[Joel Fernandes <joelagnelf@nvidia.com>]

Use checked_add() when computing the end offset in the frombytes_at()
helper function. This function is called with firmware-provided offsets.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 drivers/gpu/nova-core/firmware/booter.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/firmware/booter.rs b/drivers/gpu/nova-core/firmware/booter.rs
index f5ad619dc055..1e2b2efe838f 100644
--- a/drivers/gpu/nova-core/firmware/booter.rs
+++ b/drivers/gpu/nova-core/firmware/booter.rs
@@ -43,8 +43,9 @@
 /// Local convenience function to return a copy of `S` by reinterpreting the bytes starting at
 /// `offset` in `slice`.
 fn frombytes_at<S: FromBytes + Sized>(slice: &[u8], offset: usize) -> Result<S> {
+    let end = offset.checked_add(size_of::<S>()).ok_or(EINVAL)?;
     slice
-        .get(offset..offset + size_of::<S>())
+        .get(offset..end)
         .and_then(S::from_bytes_copy)
         .ok_or(EINVAL)
 }
-- 
2.34.1