gpu: nova-core: vbios: use checked arithmetic for bios image range end

`read_bios_image_at_offset` is called with a length from the VBIOS
header, so we should be more defensive here and use checked arithmetic.

Fixes: 6fda04e7f0cd ("gpu: nova-core: vbios: Add base support for VBIOS construction and iteration")
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
Link: https://patch.msgid.link/20260525-fix-vbios-v5-2-e5e455251537@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

diff --git a/drivers/gpu/nova-core/vbios.rs b/drivers/gpu/nova-core/vbios.rs
index 7bec81a3734069e570184876a84d623b286892c3..1809284337664f744192d78f6a821ec8a00b9c9c 100644 (file)
--- a/drivers/gpu/nova-core/vbios.rs
+++ b/drivers/gpu/nova-core/vbios.rs
@@ -238,8 +238,8 @@ impl<'a> VbiosIterator<'a> {
         len: usize,
         context: &str,
     ) -> Result<BiosImage> {
-        let data_len = self.data.len();
-        if offset + len > data_len {
+        let end = offset.checked_add(len).ok_or(EINVAL)?;
+        if end > self.data.len() {
             self.read_more_at_offset(offset, len).inspect_err(|e| {
                 dev_err!(
                     self.dev,
@@ -250,7 +250,7 @@ impl<'a> VbiosIterator<'a> {
             })?;
         }
 
-        BiosImage::new(self.dev, &self.data[offset..offset + len]).inspect_err(|err| {
+        BiosImage::new(self.dev, &self.data[offset..end]).inspect_err(|err| {
             dev_err!(
                 self.dev,
                 "Failed to {} at offset {:#x}: {:?}\n",