From 3fc9188fa8cb939539e568a0ef602892aa3fc59a Mon Sep 17 00:00:00 2001
From: Kevin Enderby <enderby@apple.com>
Date: Fri, 3 Nov 2017 21:32:44 +0000
Subject: [PATCH] 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

llvm-svn: 317373
---
 .../X86/Inputs/macho-invalid-reloc-section-index         | Bin 0 -> 2768 bytes
 llvm/test/tools/llvm-objdump/X86/malformed-machos.test   |   3 +++
 llvm/tools/llvm-objdump/llvm-objdump.cpp                 |  15 +++++++++++++--
 3 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/tools/llvm-objdump/X86/Inputs/macho-invalid-reloc-section-index

diff --git a/llvm/test/tools/llvm-objdump/X86/Inputs/macho-invalid-reloc-section-index b/llvm/test/tools/llvm-objdump/X86/Inputs/macho-invalid-reloc-section-index
new file mode 100644
index 0000000000000000000000000000000000000000..a9d0b48449b733af6a717bf6e71425bc17e2be0a
GIT binary patch
literal 2768
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z4DrMfJelahqi`@yh%p*bFWxxlp@|-dTs){r@q4o~bt!GcCI(+J`~GI$?!5Wt+t=yk
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zF+}=wP&7msdx)VuG(!_rb$1O=BeO)Vm-XT(P)c)3*^GWFfnh(!0`hw(fxryZK@5to
zFP(ik{jkmZxco*aofsTEhFBHGJmyzGpAbH+--&pfvngkSW6qgi&O6Ci$<XFUOLAyM
zpShi^$`15x2_)K$Lo0I->J9egFhQ5$%bU1njt-$~tE*vYdq0eCtmPhK3N-nx!apPY
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z*YF&f)Zm;K#|rK6&p4L-mAI3Bp*WW7Wj!YjfuBPj91kE#m?pd{&=SXMmBY&)zPBtb
ztro4{JOAyI#Bm?y>2XZ!cOrVUZpAU7Qo|)mIb<zhl;chMdtqe1ig*hAq^f=}9zSYv
zXEArT`PuiM^Rvy4pAnZVeokv0f2;8`{}EE(iGkiwO3}{Y7TGz(f>;F>kS+wnay^x9
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literal 0
HcmV?d00001

diff --git a/llvm/test/tools/llvm-objdump/X86/malformed-machos.test b/llvm/test/tools/llvm-objdump/X86/malformed-machos.test
index 292666a..e29df46 100644
--- a/llvm/test/tools/llvm-objdump/X86/malformed-machos.test
+++ b/llvm/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/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index d80f1cb..02eaa89 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/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;
-- 
2.7.4