[08/10] ELF/Aarch64: Add R_AARCH64_ADR_GOT_PAGE and R_AARCH64_LD64_GOT_LO12_NC checks

[zatrazz]

Summary

Hi ruiu, shankarke,

This is re-post of a previous attempt. This patch adds R_AARCH64_ADR_GOT_PAGE overflow and R_AARCH64_LD64_GOT_LO12_NC unaligned value checks.

[ruiu]

LGTM

lib/ReaderWriter/ELF/AArch64/AArch64RelocationHandler.cpp

static void relocR_AARCH64_LDST128_ABS_LO12_NC(uint8_t *location, uint64_t P,
   DEBUG(llvm::dbgs() << "\t\tHandle " << LLVM_FUNCTION_NAME << " -";
         llvm::dbgs() << " S: " << Twine::utohexstr(S);
         llvm::dbgs() << " A: " << Twine::utohexstr(A);
         llvm::dbgs() << " P: " << Twine::utohexstr(P);
         llvm::dbgs() << " result: " << Twine::utohexstr(result) << "\n");
   write32le(location, result | read32le(location));
 }
 
-static void relocR_AARCH64_ADR_GOT_PAGE(uint8_t *location, uint64_t P,
+static std::error_code relocR_AARCH64_ADR_GOT_PAGE(uint8_t *location, uint64_t P,
                                         uint64_t S, int64_t A) {
   uint64_t result = PAGE(S + A) - PAGE(P);
-  result >>= 12;
+  if (!isInt<32>(result))
+    return make_out_of_range_reloc_error();
+  result = (result >> 12) & 0x3FFFF;
   uint32_t immlo = result & 0x3;
   uint32_t immhi = result & 0x1FFFFC;
   immlo = immlo << 29;
   immhi = immhi << 3;
   DEBUG(llvm::dbgs() << "\t\tHandle " << LLVM_FUNCTION_NAME << " -";
         llvm::dbgs() << " S: " << Twine::utohexstr(S);
         llvm::dbgs() << " A: " << Twine::utohexstr(A);
         llvm::dbgs() << " P: " << Twine::utohexstr(P);
         llvm::dbgs() << " immhi: " << Twine::utohexstr(immhi);
         llvm::dbgs() << " immlo: " << Twine::utohexstr(immlo);
         llvm::dbgs() << " result: " << Twine::utohexstr(result) << "\n");
   write32le(location, immlo | immhi | read32le(location));
+  return std::error_code();
 }
 
 // R_AARCH64_LD64_GOT_LO12_NC
-static void relocR_AARCH64_LD64_GOT_LO12_NC(uint8_t *location, uint64_t P,
+static std::error_code relocR_AARCH64_LD64_GOT_LO12_NC(uint8_t *location, uint64_t P,
                                             uint64_t S, int64_t A) {
   int32_t result = S + A;
-  DEBUG(llvm::dbgs() << "\t\tHandle " << LLVM_FUNCTION_NAME << " -";
-        llvm::dbgs() << " S: " << Twine::utohexstr(S);
+  DEBUG(llvm::dbgs() << " S: " << Twine::utohexstr(S);
         llvm::dbgs() << " A: " << Twine::utohexstr(A);
         llvm::dbgs() << " P: " << Twine::utohexstr(P);
         llvm::dbgs() << " result: " << Twine::utohexstr(result) << "\n");
+  if ((result & 0x7) != 0)
+    return make_unaligned_range_reloc_error();
   result &= 0xFF8;
   result <<= 7;
   write32le(location, result | read32le(location));
+  return std::error_code();
 }
 
 // ADD_AARCH64_GOTRELINDEX
 static void relocADD_AARCH64_GOTRELINDEX(uint8_t *location, uint64_t P,
                                          uint64_t S, int64_t A) {
   int32_t result = S + A;
   DEBUG(llvm::dbgs() << "\t\tHandle " << LLVM_FUNCTION_NAME << " -";
         llvm::dbgs() << " S: " << Twine::utohexstr(S);
std::error_code AArch64TargetRelocationHandler::applyRelocation(
   case R_AARCH64_CALL26:
   case R_AARCH64_JUMP26:
     relocJump26(loc, reloc, target, addend);
     break;
   case R_AARCH64_CONDBR19:
     relocR_AARCH64_CONDBR19(loc, reloc, target, addend);
     break;
   case R_AARCH64_ADR_GOT_PAGE:
-    relocR_AARCH64_ADR_GOT_PAGE(loc, reloc, target, addend);
-    break;
+    return relocR_AARCH64_ADR_GOT_PAGE(loc, reloc, target, addend);
   case R_AARCH64_LD64_GOT_LO12_NC:
-    relocR_AARCH64_LD64_GOT_LO12_NC(loc, reloc, target, addend);
-    break;
+    return relocR_AARCH64_LD64_GOT_LO12_NC(loc, reloc, target, addend);
   case R_AARCH64_LDST8_ABS_LO12_NC:
     relocR_AARCH64_LDST8_ABS_LO12_NC(loc, reloc, target, addend);
     break;
   case R_AARCH64_LDST16_ABS_LO12_NC:
     relocR_AARCH64_LDST16_ABS_LO12_NC(loc, reloc, target, addend);
     break;
   case R_AARCH64_LDST32_ABS_LO12_NC:
     relocR_AARCH64_LDST32_ABS_LO12_NC(loc, reloc, target, addend);

lib/ReaderWriter/ELF/TargetHandler.h

 inline std::error_code make_unhandled_reloc_error() {
   return make_dynamic_error_code(Twine("Unhandled reference type"));
 }
 
 inline std::error_code make_out_of_range_reloc_error() {
   return make_dynamic_error_code(Twine("Relocation out of range"));
 }
 
+inline std::error_code make_unaligned_range_reloc_error() {
+  return make_dynamic_error_code(Twine("Relocation not aligned"));
+}
+
 } // end namespace elf
 } // end namespace lld
 
 #endif