[llvm] f9b5f69 - [JITLink][ELF/x86-64] Range check 32-bit relocs.

[Lang Hames via llvm-commits]

Author: Lang Hames
Date: 2021-01-22T15:59:19+11:00
New Revision: f9b5f6937ebed5dccabfc3c287f11d18b68a36f6

URL: https://github.com/llvm/llvm-project/commit/f9b5f6937ebed5dccabfc3c287f11d18b68a36f6
DIFF: https://github.com/llvm/llvm-project/commit/f9b5f6937ebed5dccabfc3c287f11d18b68a36f6.diff

LOG: [JITLink][ELF/x86-64] Range check 32-bit relocs.

Also switch to using little_<b> / ulittle_<b> types to write results for
consistency with MachO.

Added: 
    

Modified: 
    llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp

Removed: 
    


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diff  --git a/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp b/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
index 30366a82a043..244975f4a51a 100644
--- a/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
+++ b/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
@@ -670,6 +670,17 @@ class ELFJITLinker_x86_64 : public JITLinker<ELFJITLinker_x86_64> {
     return getELFX86RelocationKindName(R);
   }
 
+  static Error targetOutOfRangeError(const Block &B, const Edge &E) {
+    std::string ErrMsg;
+    {
+      raw_string_ostream ErrStream(ErrMsg);
+      ErrStream << "Relocation target out of range: ";
+      printEdge(ErrStream, B, E, getELFX86RelocationKindName(E.getKind()));
+      ErrStream << "\n";
+    }
+    return make_error<JITLinkError>(std::move(ErrMsg));
+  }
+
   Error applyFixup(Block &B, const Edge &E, char *BlockWorkingMem) const {
     using namespace ELF_x86_64_Edges;
     using namespace llvm::support;
@@ -681,12 +692,15 @@ class ELFJITLinker_x86_64 : public JITLinker<ELFJITLinker_x86_64> {
     case ELFX86RelocationKind::PCRel32:
     case ELFX86RelocationKind::PCRel32GOTLoad: {
       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
-      endian::write32le(FixupPtr, Value);
+      if (Value < std::numeric_limits<int32_t>::min() ||
+          Value > std::numeric_limits<int32_t>::max())
+        return targetOutOfRangeError(B, E);
+      *(little32_t *)FixupPtr = Value;
       break;
     }
     case ELFX86RelocationKind::Pointer64: {
       int64_t Value = E.getTarget().getAddress() + E.getAddend();
-      endian::write64le(FixupPtr, Value);
+      *(ulittle64_t *)FixupPtr = Value;
       break;
     }
     }