Fixing a flaky Linux exploitability unittest.

src/processor/exploitability_unittest.cc

 // Copyright (c) 2010, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 29 matching lines @@
 #ifndef _WIN32
 #include "processor/exploitability_linux.h"
 #endif  // _WIN32
 #include "processor/simple_symbol_supplier.h"
 
 #ifndef _WIN32
 namespace google_breakpad {
 
 class ExploitabilityLinuxTest : public ExploitabilityLinux {
  public:
+  using ExploitabilityLinux::CalculateAddress;
   using ExploitabilityLinux::DisassembleBytes;
+  using ExploitabilityLinux::GetObjdumpInstructionLine;
   using ExploitabilityLinux::TokenizeObjdumpInstruction;
-  using ExploitabilityLinux::CalculateAddress;
 };
 
 class ExploitabilityLinuxTestMinidumpContext : public MinidumpContext {
  public:
   explicit ExploitabilityLinuxTestMinidumpContext(
       const MDRawContextAMD64& context) : MinidumpContext(NULL) {
     valid_ = true;
     SetContextAMD64(new MDRawContextAMD64(context));
     SetContextFlags(MD_CONTEXT_AMD64);
   }
@@ skipping 130 matching lines @@
                                                         buffer));
   std::stringstream objdump_stream;
   objdump_stream.str(string(buffer));
   string line = "";
   while (line.find("<.data>") == string::npos)
     getline(objdump_stream, line);
   getline(objdump_stream, line);
   ASSERT_EQ(line, "   0:\tc7 00 05 00 00 00    \tmov    DWORD PTR [rax],0x5");
 }
 
+TEST(ExploitabilityLinuxUtilsTest, GetObjdumpInstructionLine) {
+  string disassebly =
+      "\n"
+      "/tmp/breakpad_mem_region-raw_bytes-tMmMo0:     file format binary\n"
+      "\n"
+      "\n"
+      "Disassembly of section .data:\n"
+      "\n"
+      "0000000000000000 <.data>:\n"
+      "   0:\tc7 00 01 00 00 00    \tmov    DWORD PTR [rax],0x1\n"

[mmandlis, 2016/02/16 19:21:16]

IIUC, we are after the line starting with 0: that follows the <.data> line.
Maybe it's worth putting another 0: line before the <.data> line, and make sure
the right one is returned. And maybe even an additional case for 0: preceding
the <.data>, so that false is returned.

[ivanpe, 2016/02/16 19:41:43]

Done.

+      "   6:\t5d                   \tpop    rbp\n"
+      "   7:\tc3                   \tret    \n"
+      "   8:\t55                   \tpush   rbp\n"
+      "   9:\t48 89 e5             \tmov    rbp,rsp\n"
+      "   c:\t53                   \tpush   rbx\n"
+      "   d:\t48                   \trex.W\n"
+      "   e:\t81                   \t.byte 0x81\n";
+  string line;
+  EXPECT_TRUE(ExploitabilityLinuxTest::GetObjdumpInstructionLine(
+      disassebly.c_str(), &line));
+  EXPECT_EQ("   0:\tc7 00 01 00 00 00    \tmov    DWORD PTR [rax],0x1", line);
+}
+
 TEST(ExploitabilityLinuxUtilsTest, TokenizeObjdumpInstructionTest) {
   ASSERT_FALSE(ExploitabilityLinuxTest::TokenizeObjdumpInstruction("",
                                                                    NULL,
                                                                    NULL,
                                                                    NULL));
   string line = "0: c7 00 05 00 00 00     mov    DWORD PTR [rax],0x5";
   string operation = "";
   string dest = "";
   string src = "";
   ASSERT_TRUE(ExploitabilityLinuxTest::TokenizeObjdumpInstruction(line,
@@ skipping 39 matching lines @@
   ASSERT_FALSE(ExploitabilityLinuxTest::CalculateAddress("rdx+rax",
                                                          context,
                                                          &write_address));
   ASSERT_FALSE(ExploitabilityLinuxTest::CalculateAddress("0x3482+0x4D2",
                                                          context,
                                                          &write_address));
 }
 #endif  // _WIN32
 
 }  // namespace