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Commit 4568f4bc authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Verify that the elf matches the expected arch. 

To avoid a case where a malicious app might try and trick the system to
create an elf and register object that mismatches, always verify that they
are the same arch.

Test: Ran unit tests.
Change-Id: I66978e9e02f8e4f396856912e7019528ead4838e
parent 2a846072

libbacktrace/UnwindStack.cpp

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ bool Backtrace::Unwind(unwindstack::Regs* regs, BacktraceMap* back_map, 
  unwindstack::Unwinder unwinder(MAX_BACKTRACE_FRAMES + num_ignore_frames, stack_map->stack_maps(),

                                 regs, stack_map->process_memory());

  unwinder.SetResolveNames(stack_map->ResolveNames());

  stack_map->SetArch(regs->Arch());

  if (stack_map->GetJitDebug() != nullptr) {

    unwinder.SetJitDebug(stack_map->GetJitDebug(), regs->Arch());

  }

libbacktrace/UnwindStackMap.cpp

+12 −1
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <unwindstack/Elf.h>

#include <unwindstack/MapInfo.h>

#include <unwindstack/Maps.h>

#include <unwindstack/Regs.h>



#include "UnwindStackMap.h"
@@ -106,7 +107,17 @@ std::string UnwindStackMap::GetFunctionName(uint64_t pc, uint64_t* offset) { 
    return "";

  }



  unwindstack::Elf* elf = map_info->GetElf(process_memory());

  if (arch_ == unwindstack::ARCH_UNKNOWN) {

    if (pid_ == getpid()) {

      arch_ = unwindstack::Regs::CurrentArch();

    } else {

      // Create a remote regs, to figure out the architecture.

      std::unique_ptr<unwindstack::Regs> regs(unwindstack::Regs::RemoteGet(pid_));

      arch_ = regs->Arch();

    }

  }



  unwindstack::Elf* elf = map_info->GetElf(process_memory(), arch_);



  std::string name;

  uint64_t func_offset;

libbacktrace/UnwindStackMap.h

+5 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#if !defined(NO_LIBDEXFILE_SUPPORT)

#include <unwindstack/DexFiles.h>

#endif

#include <unwindstack/Elf.h>

#include <unwindstack/JitDebug.h>

#include <unwindstack/Maps.h>
@@ -58,6 +59,8 @@ class UnwindStackMap : public BacktraceMap { 
  unwindstack::DexFiles* GetDexFiles() { return dex_files_.get(); }

#endif



  void SetArch(unwindstack::ArchEnum arch) { arch_ = arch; }



 protected:

  uint64_t GetLoadBias(size_t index) override;
@@ -67,6 +70,8 @@ class UnwindStackMap : public BacktraceMap { 
#if !defined(NO_LIBDEXFILE_SUPPORT)

  std::unique_ptr<unwindstack::DexFiles> dex_files_;

#endif



  unwindstack::ArchEnum arch_ = unwindstack::ARCH_UNKNOWN;

};



class UnwindStackOfflineMap : public UnwindStackMap {

libunwindstack/DexFiles.cpp

+2 −2
Original line number Diff line number Diff line
@@ -54,8 +54,8 @@ DexFiles::~DexFiles() { 
  }

}



void DexFiles::SetArch(ArchEnum arch) {

  switch (arch) {

void DexFiles::ProcessArch() {

  switch (arch()) {

    case ARCH_ARM:

    case ARCH_MIPS:

    case ARCH_X86:

libunwindstack/Elf.cpp

+5 −0
Original line number Diff line number Diff line
@@ -88,6 +88,11 @@ void Elf::InitGnuDebugdata() { 
  }

}



void Elf::Invalidate() {

  interface_.reset(nullptr);

  valid_ = false;

}



bool Elf::GetSoname(std::string* name) {

  std::lock_guard<std::mutex> guard(lock_);

  return valid_ && interface_->GetSoname(name);