[PATCH] D37070: [WebAssembly] Fix overflow for input without version

[Jonas Devlieghere via Phabricator via llvm-commits]

JDevlieghere updated this revision to Diff 112425.
JDevlieghere added a comment.

Running the tests identified an off-by-one error: must be `<` rather than `<=`


Repository:
  rL LLVM

https://reviews.llvm.org/D37070

Files:
  lib/Object/WasmObjectFile.cpp
  test/Object/Inputs/WASM/missing-version.wasm
  test/Object/wasm-missing-version.test


Index: test/Object/wasm-missing-version.test
===================================================================
--- /dev/null
+++ test/Object/wasm-missing-version.test
@@ -0,0 +1,2 @@
+# RUN: not llvm-objdump -h %p/Inputs/WASM/missing-version.wasm 2>&1 | FileCheck %s
+# CHECK: {{.*}}: Missing version number
Index: lib/Object/WasmObjectFile.cpp
===================================================================
--- lib/Object/WasmObjectFile.cpp
+++ lib/Object/WasmObjectFile.cpp
@@ -203,15 +203,23 @@
                                   object_error::parse_failed);
     return;
   }
+
+  const uint8_t *Eof = getPtr(getData().size());
   const uint8_t *Ptr = getPtr(4);
+
+  if (Ptr + 4 > Eof) {
+    Err = make_error<StringError>("Missing version number",
+                                  object_error::parse_failed);
+    return;
+  }
+
   Header.Version = readUint32(Ptr);
   if (Header.Version != wasm::WasmVersion) {
     Err = make_error<StringError>("Bad version number",
                                   object_error::parse_failed);
     return;
   }
 
-  const uint8_t *Eof = getPtr(getData().size());
   WasmSection Sec;
   while (Ptr < Eof) {
     if ((Err = readSection(Sec, Ptr, getPtr(0))))


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