PayloadWriter: Don't set data_offset for ZERO and DISCARD operations

`data_offset` should only be set if the operation references data in the blob section of the payload. This is never encountered when patching a file because avbroot does not produce ZERO/DISCARD operations, but we should ensure valid outputs in all scenarios. Signed-off-by: Andrew Gunnerson <[email protected]>
chenxiaolong · Sep 7, 2023 · a46bc16 · a46bc16
1 parent f93dc55
commit a46bc16
Showing 1 changed file with 9 additions and 1 deletion.
diff --git a/avbroot/src/format/payload.rs b/avbroot/src/format/payload.rs
@@ -294,7 +294,15 @@ impl<W: Write> PayloadWriter<W> {
         // The blob must contain all data in sequential order with no gaps.
         for p in &mut header.manifest.partitions {
             for op in &mut p.operations {
-                op.data_offset = Some(blob_size);
+                match op.type_pb {
+                    mod_InstallOperation::Type::ZERO | mod_InstallOperation::Type::DISCARD => {
+                        // The field must be left unset when the blob contains
+                        // no data for the operation.
+                    }
+                    _ => {
+                        op.data_offset = Some(blob_size);
+                    }
+                }
 
                 if let Some(length) = op.data_length {
                     blob_size += length;