From: Kevin Enderby <enderby@apple.com>
Date: Fri, 3 Nov 2017 21:32:44 +0000 (+0000)
Subject: Fix a crash in llvm-objdump when printing a bad x86_64 relocation in a Mach-O
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ce8f24e6d75e12371b723070fbcd546ebb01598b;p=llvm

Fix a crash in llvm-objdump when printing a bad x86_64 relocation in a Mach-O
file with a bad section number.

rdar://35207539


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317373 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/test/tools/llvm-objdump/X86/Inputs/macho-invalid-reloc-section-index b/test/tools/llvm-objdump/X86/Inputs/macho-invalid-reloc-section-index
new file mode 100644
index 00000000000..a9d0b48449b
Binary files /dev/null and b/test/tools/llvm-objdump/X86/Inputs/macho-invalid-reloc-section-index differ
diff --git a/test/tools/llvm-objdump/X86/malformed-machos.test b/test/tools/llvm-objdump/X86/malformed-machos.test
index 292666a3725..e29df464a4e 100644
--- a/test/tools/llvm-objdump/X86/malformed-machos.test
+++ b/test/tools/llvm-objdump/X86/malformed-machos.test
@@ -66,3 +66,6 @@ INVALID-SYMBOL-LIB_ORDINAL: macho-invalid-symbol-lib_ordinal': truncated or malf
 
 RUN: not llvm-objdump -macho -objc-meta-data %p/Inputs/macho-invalid-bind-entry 2>&1 | FileCheck -check-prefix INVALID-BIND-ENTRY %s
 INVALID-BIND-ENTRY: macho-invalid-bind-entry': truncated or malformed object (for BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB bad library ordinal: 83 (max 0) for opcode at: 0x0)
+
+RUN: llvm-objdump -macho -r %p/Inputs/macho-invalid-reloc-section-index | FileCheck -check-prefix INVALID-RELOC-SECTION-INDEX %s
+INVALID-RELOC-SECTION-INDEX: 0000000000000021 X86_64_RELOC_UNSIGNED 8388613 (?,?)
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index d80f1cb049d..02eaa89f088 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -865,8 +865,19 @@ static void printRelocationTargetName(const MachOObjectFile *O,
   } else {
     section_iterator SI = O->section_begin();
     // Adjust for the fact that sections are 1-indexed.
-    advance(SI, Val - 1);
-    SI->getName(S);
+    if (Val == 0) {
+      fmt << "0 (?,?)";
+      return;
+    }
+    uint32_t i = Val - 1;
+    while (i != 0 && SI != O->section_end()) {
+      i--;
+      advance(SI, 1);
+    }
+    if (SI == O->section_end())
+      fmt << Val << " (?,?)";
+    else
+      SI->getName(S);
   }
 
   fmt << S;