PR feedback

Signed-off-by: Alan Jowett <[email protected]>

src/asm_files.cpp

@@ -475,15 +475,11 @@ vector<raw_program> read_elf(std::istream& input_stream, const std::string& path
                         continue;
                     }
                     offset -= program_offset;
-
-                    // Relocation is always on a double width instruction, so check that the offset is within the
-                    // program and that offset + 1 is within the program.
-                    if (((offset / sizeof(ebpf_inst)) + 1) >= prog.prog.size()) {
+                    if (offset / sizeof(ebpf_inst) >= prog.prog.size()) {
                         throw UnmarshalError("Invalid relocation data");
                     }
 
                     ebpf_inst& reloc_inst = prog.prog[offset / sizeof(ebpf_inst)];
-                    ebpf_inst& next_reloc_inst = prog.prog[offset / sizeof(ebpf_inst) + 1];
 
                     auto [symbol_name, symbol_section_index] = get_symbol_name_and_section_index(symbols, index);
 
@@ -497,6 +493,15 @@ vector<raw_program> read_elf(std::istream& input_stream, const std::string& path
                         continue;
                     }
 
+                    // Verify that this is a map or global variable relocation.
+                    verify_load_instruction(reloc_inst, symbol_name, offset);
+
+                    // Load instructions are two instructions long, so we need to check the next instruction.
+                    if (prog.prog.size() <= offset / sizeof(ebpf_inst) + 1) {
+                        throw UnmarshalError("Invalid relocation data");
+                    }
+                    ebpf_inst& next_reloc_inst = prog.prog[offset / sizeof(ebpf_inst) + 1];
+
                     // Perform relocation for symbols located in the maps section.
                     if (map_section_indices.contains(symbol_section_index)) {
                         relocate_map(reloc_inst, symbol_name, map_record_size_or_map_offsets, info, offset, index,