From b7aec331255e7be93652dfad94e817fd8b7be0b8 Mon Sep 17 00:00:00 2001
From: George Rimar <grimar@accesssoftek.com>
Date: Fri, 7 Oct 2016 08:51:57 +0000
Subject: [PATCH] [ELF] - Do not crash when unable to parse ELF object file.

createELFObj() may call error(...), for example when file is too short.
In that case header is not set and following line lead to crash:

EMachine = ELFObj.getHeader()->e_machine;

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D25233

llvm-svn: 283532
---
 lld/ELF/Error.cpp                         |   4 ++++
 lld/ELF/Error.h                           |   1 +
 lld/ELF/InputFiles.cpp                    |   2 +-
 lld/test/ELF/invalid/Inputs/too-short.elf | Bin 0 -> 44 bytes
 lld/test/ELF/invalid/too-short.s          |   5 +++++
 5 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 lld/test/ELF/invalid/Inputs/too-short.elf
 create mode 100644 lld/test/ELF/invalid/too-short.s

diff --git a/lld/ELF/Error.cpp b/lld/ELF/Error.cpp
index 4649331..729888e 100644
--- a/lld/ELF/Error.cpp
+++ b/lld/ELF/Error.cpp
@@ -47,4 +47,8 @@ void elf::fatal(const Twine &Msg) {
   exit(1);
 }
 
+void elf::fatal(std::error_code EC, const Twine &Prefix) {
+  fatal(Prefix + ": " + EC.message());
+}
+
 } // namespace lld
diff --git a/lld/ELF/Error.h b/lld/ELF/Error.h
index 61a0aeb..83392bd 100644
--- a/lld/ELF/Error.h
+++ b/lld/ELF/Error.h
@@ -45,6 +45,7 @@ template <typename T> void error(const ErrorOr<T> &V, const Twine &Prefix) {
 }
 
 LLVM_ATTRIBUTE_NORETURN void fatal(const Twine &Msg);
+LLVM_ATTRIBUTE_NORETURN void fatal(std::error_code EC, const Twine &Prefix);
 
 template <class T> T check(ErrorOr<T> E) {
   if (auto EC = E.getError())
diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index e8f2bee..5b0ce10 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -57,7 +57,7 @@ template <class ELFT> static ELFFile<ELFT> createELFObj(MemoryBufferRef MB) {
   std::error_code EC;
   ELFFile<ELFT> F(MB.getBuffer(), EC);
   if (EC)
-    error(EC, "failed to read " + MB.getBufferIdentifier());
+    fatal(EC, "failed to read " + MB.getBufferIdentifier());
   return F;
 }
 
diff --git a/lld/test/ELF/invalid/Inputs/too-short.elf b/lld/test/ELF/invalid/Inputs/too-short.elf
new file mode 100644
index 0000000000000000000000000000000000000000..077f392f1dc4dda9e934b9cb22da021e02d33ece
GIT binary patch
literal 44
wcmb<-^>JfjWMp8NGl4-!o*^-dVR33kd|FYWBm+YV1H=D+uNV{<Kme!&0P%SW5C8xG

literal 0
HcmV?d00001

diff --git a/lld/test/ELF/invalid/too-short.s b/lld/test/ELF/invalid/too-short.s
new file mode 100644
index 0000000..10bc429f
--- /dev/null
+++ b/lld/test/ELF/invalid/too-short.s
@@ -0,0 +1,5 @@
+# REQUIRES: x86
+
+## too-short.elf file is a truncated ELF.
+# RUN: not ld.lld %S/Inputs/too-short.elf -o %t 2>&1 | FileCheck %s
+# CHECK: failed to read
-- 
2.7.4