[PATCH 10/13] ELF/AARCH64: Add overflow check for R_AARCH64_CALL26 and R_AARCH64_JUMP26

[zatrazz]

Summary

Add support for overflow checking when processing
R_AARCH64_CALL26 and R_AARCH64_JUMP26.

lib/ReaderWriter/ELF/AArch64/AArch64RelocationHandler.cpp

static void relocR_AARCH64_ADD_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 relocJump26(uint8_t *location, uint64_t P, uint64_t S, int64_t A) {
+/// \brief R_AARCH64_CALL26 and R_AARCH64_JUMP26
+static std::error_code relocJump26(uint8_t *location, uint64_t P, uint64_t S,
+                                   int64_t A) {
   int32_t result = (int32_t)((S + A) - P);
+  if (!isInt<27>(result))
+    return make_out_of_range_reloc_error();
   result &= 0x0FFFFFFC;
   result >>= 2;
   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));
+  return std::error_code();
 }
 
 /// \brief R_AARCH64_CONDBR19
 static void relocR_AARCH64_CONDBR19(uint8_t *location, uint64_t P, uint64_t S,
                                     int64_t A) {
   int32_t result = (int32_t)((S + A) - P);
   result &= 0x01FFFFC;
   result <<= 3;
case R_AARCH64_ADR_PREL_LO21:
     return relocR_AARCH64_ADR_PREL_LO21(location, relocVAddress, targetVAddress,
                                         ref.addend());
   case R_AARCH64_ADD_ABS_LO12_NC:
     relocR_AARCH64_ADD_ABS_LO12_NC(location, relocVAddress, targetVAddress,
                                    ref.addend());
     break;
   case R_AARCH64_CALL26:
   case R_AARCH64_JUMP26:
-    relocJump26(location, relocVAddress, targetVAddress, ref.addend());
-    break;
+    return relocJump26(location, relocVAddress, targetVAddress, ref.addend());
   case R_AARCH64_CONDBR19:
     relocR_AARCH64_CONDBR19(location, relocVAddress, targetVAddress,
                             ref.addend());
     break;
   case R_AARCH64_ADR_GOT_PAGE:
     return relocR_AARCH64_ADR_GOT_PAGE(location, relocVAddress, targetVAddress,
                                        ref.addend());
   case R_AARCH64_LD64_GOT_LO12_NC:

test/elf/AArch64/rel-adr_prel_lo21-overflow.test

 # Check handling of R_AARCH64_ADR_PREL_PG_HI21 relocation.
 # RUN: yaml2obj -format=elf %s > %t-obj
 # RUN: not lld -flavor gnu -target arm64 -o %t-exe %t-obj
 
-# CHECK: Relocation out of range in file {{.*}}: reference from _start+0 to data1+1048577 of type 274 (R_AARCH64_ADR_PREL_LO21) 
+# CHECK: Relocation out of range in file {{.*}}: reference from _start+0 to data1+1048577 of type 274 (R_AARCH64_ADR_PREL_LO21)
 
 !ELF
 FileHeader: !FileHeader
   Class: ELFCLASS64
   Data: ELFDATA2LSB
   Type: ET_REL
   Machine: EM_AARCH64