[05/10] ELF/AArch64: Check ADR_PREL_PG_HI21 for overflow

[zatrazz]

Summary

Hi ruiu, shankarke,

This is re-post of a previous attempt. Add support for overflow checking when processing R_AARCH64_ADR_PREL_PG_HI21 relocations and add test.

Patch Will Newton.

[ruiu]

LGTM

lib/ReaderWriter/ELF/AArch64/AArch64RelocationHandler.cpp

120

You can now remove this?

[zatrazz]

I will remove it, thanks.

lib/ReaderWriter/ELF/AArch64/AArch64RelocationHandler.cpp

static std::error_code relocR_AARCH64_PREL16(uint8_t *location, uint64_t P,
   int64_t result = S + A - P;
   if (!withinSignedUnsignedRange(result, 16))
     return make_out_of_range_reloc_error();
   write16le(location, result + read16le(location));
   return std::error_code();
 }
 
 /// \brief R_AARCH64_ADR_PREL_PG_HI21 - Page(S+A) - Page(P)
-static void relocR_AARCH64_ADR_PREL_PG_HI21(uint8_t *location, uint64_t P,
-                                            uint64_t S, int64_t A) {
-  uint64_t result = (PAGE(S + A) - PAGE(P));
+static std::error_code relocR_AARCH64_ADR_PREL_PG_HI21(uint8_t *location,
+                                                       uint64_t P, uint64_t S,
+                                                       int64_t A) {
+  int64_t result = PAGE(S + A) - PAGE(P);
+  if (!isInt<32>(result))
+    return make_out_of_range_reloc_error();
   result = result >> 12;
   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();
   // TODO: Make sure this is correct!
 }
 
 /// \brief R_AARCH64_ADR_PREL_LO21 - S + A - P
 static void relocR_AARCH64_ADR_PREL_LO21(uint8_t *location, uint64_t P,
                                          uint64_t S, int64_t A) {
   uint64_t result = (S + A) - P;
   uint32_t immlo = result & 0x3;
   uint32_t immhi = result & 0x1FFFFC;
case R_AARCH64_PREL16:
     return relocR_AARCH64_PREL16(loc, reloc, target, addend);
   // Runtime only relocations. Ignore here.
   case R_AARCH64_RELATIVE:
   case R_AARCH64_IRELATIVE:
   case R_AARCH64_JUMP_SLOT:
   case R_AARCH64_GLOB_DAT:
     break;
   case R_AARCH64_ADR_PREL_PG_HI21:
-    relocR_AARCH64_ADR_PREL_PG_HI21(loc, reloc, target, addend);
-    break;
+    return relocR_AARCH64_ADR_PREL_PG_HI21(loc, reloc, target, addend);
   case R_AARCH64_ADR_PREL_LO21:
     relocR_AARCH64_ADR_PREL_LO21(loc, reloc, target, addend);
     break;
   case R_AARCH64_ADD_ABS_LO12_NC:
     relocR_AARCH64_ADD_ABS_LO12_NC(loc, reloc, target, addend);
     break;
   case R_AARCH64_CALL26:
   case R_AARCH64_JUMP26:

test/elf/AArch64/rel-adr_prel_pg_hi21-overflow.test

+# Check handling of R_AARCH64_ADR_PREL_PG_HI21 relocation overflow.
+# RUN: yaml2obj -format=elf %s > %t-obj
+# RUN: not lld -flavor gnu -target arm64 -o %t-exe %t-obj
+
+# CHECK-DAG: Relocation out of range in file {{.*}}: reference from _start+0 to data1+2147483649 of type 275 (R_AARCH64_ADR_PREL_PG_HI21)
+
+!ELF
+FileHeader: !FileHeader
+  Class: ELFCLASS64
+  Data: ELFDATA2LSB
+  Type: ET_REL
+  Machine: EM_AARCH64
+
+Sections:
+- Name: .text
+  Type: SHT_PROGBITS
+  Content: "00000090"
+  AddressAlign: 16
+  Flags: [SHF_ALLOC, SHF_EXECINSTR]
+
+- Name: .data
+  Type: SHT_PROGBITS
+  Content: "00000000"
+  AddressAlign: 4096
+  Flags: [SHF_ALLOC, SHF_WRITE]
+
+- Name: .rela.text
+  Type: SHT_RELA
+  Info: .text
+  AddressAlign: 8
+  Relocations:
+    - Offset: 0x0
+      Symbol: data1
+      Type: R_AARCH64_ADR_PREL_PG_HI21
+      Addend: 0x80000001
+
+Symbols:
+  Global:
+    - Name: _start
+      Section: .text
+      Value: 0x0
+      Size: 4
+    - Name: data1
+      Section: .data
+      Size: 8

test/elf/AArch64/rel-adr_prel_pg_hi21.test

+# Check handling of R_AARCH64_ADR_PREL_PG_HI21 relocation.
+# RUN: yaml2obj -format=elf %s > %t-obj
+# RUN: lld -flavor gnu -target arm64 -o %t-exe %t-obj
+# RUN: llvm-objdump -d -t %t-exe | FileCheck %s
+
+# CHECK: Disassembly of section .text:
+# CHECK-NEXT: _start:
+# CHECK-NEXT: 4001b0: 00 00 00 d0                                   adrp  x0, #8192
+# CHECK: SYMBOL TABLE:
+# CHECK: 00402000 g  .data  00000004 data1
+
+!ELF
+FileHeader: !FileHeader
+  Class: ELFCLASS64
+  Data: ELFDATA2LSB
+  Type: ET_REL
+  Machine: EM_AARCH64
+
+Sections:
+- Name: .text
+  Type: SHT_PROGBITS
+  Content: "00000090"
+  AddressAlign: 16
+  Flags: [SHF_ALLOC, SHF_EXECINSTR]
+
+- Name: .data
+  Type: SHT_PROGBITS
+  Content: "00000000"
+  AddressAlign: 4096
+  Flags: [SHF_ALLOC, SHF_WRITE]
+
+- Name: .rela.text
+  Type: SHT_RELA
+  Info: .text
+  AddressAlign: 8
+  Relocations:
+    - Offset: 0x0
+      Symbol: data1
+      Type: R_AARCH64_ADR_PREL_PG_HI21
+      Addend: 0
+
+Symbols:
+  Global:
+    - Name: _start
+      Section: .text
+      Value: 0x0
+      Size: 4
+    - Name: data1
+      Section: .data
+      Size: 8