1 files changed, 24 insertions, 4 deletions

diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 38d76afc0e6..a2d60472ed9 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -29,12 +29,12 @@ use rustc_hir::LangItem;
 use rustc_middle::dep_graph::WorkProduct;
 use rustc_middle::middle::dependency_format::Dependencies;
 use rustc_middle::ty::query::{ExternProviders, Providers};
+use rustc_serialize::{opaque, Decodable, Decoder, Encoder};
 use rustc_session::config::{CrateType, OutputFilenames, OutputType, RUST_CGU_EXT};
 use rustc_session::cstore::{self, CrateSource};
 use rustc_session::utils::NativeLibKind;
 use rustc_span::symbol::Symbol;
 use std::path::{Path, PathBuf};
-use rustc_serialize::{Decodable, Decoder, Encoder, opaque};
 
 pub mod back;
 pub mod base;
@@ -192,13 +192,18 @@ pub fn looks_like_rust_object_file(filename: &str) -> bool {
     ext2 == Some(RUST_CGU_EXT)
 }
 
-const RLINK_MAGIC: &'static [u8; 5] = b"rlink";
+const RLINK_VERSION: u32 = 1;
+const RLINK_MAGIC: &[u8] = b"rustlink";
+
 const RUSTC_VERSION: Option<&str> = option_env!("CFG_VERSION");
 
 impl CodegenResults {
     pub fn serialize_rlink(codegen_results: &CodegenResults) -> Vec<u8> {
         let mut encoder = opaque::Encoder::new(vec![]);
         encoder.emit_raw_bytes(RLINK_MAGIC).unwrap();
+        // `emit_raw_bytes` is used to make sure that the version representation does not depend on
+        // Encoder's inner representation of `u32`.
+        encoder.emit_raw_bytes(&RLINK_VERSION.to_be_bytes()).unwrap();
         encoder.emit_str(RUSTC_VERSION.unwrap()).unwrap();
 
         let mut encoder = rustc_serialize::opaque::Encoder::new(encoder.into_inner());
@@ -207,14 +212,29 @@ impl CodegenResults {
     }
 
     pub fn deserialize_rlink(data: Vec<u8>) -> Result<Self, String> {
+        // The Decodable machinery is not used here because it panics if the input data is invalid
+        // and because its internal representation may change.
         if !data.starts_with(RLINK_MAGIC) {
             return Err("The input does not look like a .rlink file".to_string());
         }
-        let mut decoder = opaque::Decoder::new(&data[RLINK_MAGIC.len()..], 0);
+        let data = &data[RLINK_MAGIC.len()..];
+        if data.len() < 4 {
+            return Err("The input does not contain version number".to_string());
+        }
+
+        let mut version_array: [u8; 4] = Default::default();
+        version_array.copy_from_slice(&data[..4]);
+        if u32::from_be_bytes(version_array) != RLINK_VERSION {
+            return Err(".rlink file was produced with encoding version {version_array}, but the current version is {RLINK_VERSION}".to_string());
+        }
+
+        let mut decoder = opaque::Decoder::new(&data[4..], 0);
         let rustc_version = decoder.read_str();
         let current_version = RUSTC_VERSION.unwrap();
         if rustc_version != current_version {
-            return Err(format!(".rlink file was produced by rustc version {rustc_version}, but the current version is {current_version}."));
+            return Err(format!(
+                ".rlink file was produced by rustc version {rustc_version}, but the current version is {current_version}."
+            ));
         }
 
         let codegen_results = CodegenResults::decode(&mut decoder);