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      1 // Copyright (c) 2013 Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
      8 //     * Redistributions of source code must retain the above copyright
      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 
     30 // exploitability_linux.cc: Linux specific exploitability engine.
     31 //
     32 // Provides a guess at the exploitability of the crash for the Linux
     33 // platform given a minidump and process_state.
     34 //
     35 // Author: Matthew Riley
     36 
     37 #include "processor/exploitability_linux.h"
     38 
     39 #include "google_breakpad/processor/process_state.h"
     40 #include "google_breakpad/processor/call_stack.h"
     41 #include "google_breakpad/processor/stack_frame.h"
     42 
     43 namespace {
     44 
     45 // This function in libc is called if the program was compiled with
     46 // -fstack-protector and a function's stack canary changes.
     47 const char kStackCheckFailureFunction[] = "__stack_chk_fail";
     48 
     49 // This function in libc is called if the program was compiled with
     50 // -D_FORTIFY_SOURCE=2, a function like strcpy() is called, and the runtime
     51 // can determine that the call would overflow the target buffer.
     52 const char kBoundsCheckFailureFunction[] = "__chk_fail";
     53 
     54 }  // namespace
     55 
     56 namespace google_breakpad {
     57 
     58 ExploitabilityLinux::ExploitabilityLinux(Minidump *dump,
     59                                          ProcessState *process_state)
     60     : Exploitability(dump, process_state) { }
     61 
     62 ExploitabilityRating ExploitabilityLinux::CheckPlatformExploitability() {
     63   // Check the crashing thread for functions suggesting a buffer overflow or
     64   // stack smash.
     65   if (process_state_->requesting_thread() != -1) {
     66     CallStack* crashing_thread =
     67         process_state_->threads()->at(process_state_->requesting_thread());
     68     const vector<StackFrame*>& crashing_thread_frames =
     69         *crashing_thread->frames();
     70     for (size_t i = 0; i < crashing_thread_frames.size(); ++i) {
     71       if (crashing_thread_frames[i]->function_name ==
     72           kStackCheckFailureFunction) {
     73         return EXPLOITABILITY_HIGH;
     74       }
     75 
     76       if (crashing_thread_frames[i]->function_name ==
     77           kBoundsCheckFailureFunction) {
     78         return EXPLOITABILITY_HIGH;
     79       }
     80     }
     81   }
     82 
     83   return EXPLOITABILITY_NONE;
     84 }
     85 
     86 }  // namespace google_breakpad
     87