Add a *purpose* property to ELF relocations

romainthomas · romainthomas · commit b7b0bde4d51c · 2017-07-11T11:22:21.000+02:00
Adding such property enables to store plt/got and dynamic relocations in a same container. (related to #51)
diff --git a/api/python/ELF/objects/pyBinary.cpp b/api/python/ELF/objects/pyBinary.cpp
@@ -30,7 +30,7 @@ void init_ELF_Binary_class(py::module& m) {
 
   // Binary object
   py::class_<Binary, LIEF::Binary>(m, "Binary", "ELF binary representation")
-    .def(py::init<const std::string &, ELF_CLASS>())
+    .def(py::init<const std::string&, ELF_CLASS>())
 
     .def_property_readonly("type",
         &Binary::type,
@@ -77,12 +77,12 @@ void init_ELF_Binary_class(py::module& m) {
         py::return_value_policy::reference_internal)
 
     .def_property_readonly("dynamic_relocations",
-        static_cast<no_const_getter<it_relocations>>(&Binary::get_dynamic_relocations),
+        static_cast<no_const_getter<it_dynamic_relocations>>(&Binary::get_dynamic_relocations),
         "Return an iterator to PLT/GOT " RST_CLASS_REF(lief.ELF.Relocation) "",
         py::return_value_policy::reference_internal)
 
     .def_property_readonly("pltgot_relocations",
-        static_cast<no_const_getter<it_relocations>>(&Binary::get_pltgot_relocations),
+        static_cast<no_const_getter<it_pltgot_relocations>>(&Binary::get_pltgot_relocations),
         "Return an iterator to dynamics " RST_CLASS_REF(lief.ELF.Relocation) "",
         py::return_value_policy::reference_internal)
 
diff --git a/api/python/ELF/objects/pyRelocation.cpp b/api/python/ELF/objects/pyRelocation.cpp
@@ -40,6 +40,11 @@ void init_ELF_Relocation_class(py::module& m) {
         static_cast<setter_t<int64_t>>(&Relocation::addend),
         "Additional value")
 
+    .def_property("purpose",
+        static_cast<getter_t<RELOCATION_PURPOSES>>(&Relocation::purpose),
+        static_cast<setter_t<RELOCATION_PURPOSES>>(&Relocation::purpose),
+        "Purpose (" RST_CLASS_REF(lief.ELF.RELOCATION_PURPOSES) ") of the relocation")
+
     .def_property("type",
         static_cast<getter_t<uint32_t>>(&Relocation::type),
         static_cast<setter_t<uint32_t>>(&Relocation::type),
diff --git a/api/python/ELF/pyELFStructures.cpp b/api/python/ELF/pyELFStructures.cpp
@@ -905,4 +905,12 @@ void init_ELF_Structures_enum(py::module& m) {
     .value(PY_ENUM(NOTE_ABIS::ELF_NOTE_OS_NETBSD))
     .value(PY_ENUM(NOTE_ABIS::ELF_NOTE_OS_SYLLABLE))
     .export_values();
+
+
+  py::enum_<RELOCATION_PURPOSES>(m, "RELOCATION_PURPOSES")
+    .value(PY_ENUM(RELOCATION_PURPOSES::RELOC_PURPOSE_NONE))
+    .value(PY_ENUM(RELOCATION_PURPOSES::RELOC_PURPOSE_PLTGOT))
+    .value(PY_ENUM(RELOCATION_PURPOSES::RELOC_PURPOSE_DYNAMIC))
+    .value(PY_ENUM(RELOCATION_PURPOSES::RELOC_PURPOSE_OBJECT))
+    .export_values();
 }
diff --git a/api/python/pyIterators.cpp b/api/python/pyIterators.cpp
@@ -31,7 +31,7 @@ void init_LIEF_iterators(py::module& m) {
   init_ref_iterator<LIEF::ELF::it_segments>(m);
   init_ref_iterator<LIEF::ELF::it_dynamic_entries>(m);
   init_ref_iterator<LIEF::ELF::it_symbols>(m);
-  init_ref_iterator<LIEF::ELF::it_relocations>(m);
+  init_ref_iterator<LIEF::filter_iterator<LIEF::ELF::relocations_t>>(m);
   init_ref_iterator<LIEF::ELF::it_symbols_version>(m);
   init_ref_iterator<LIEF::ELF::it_symbols_version_requirement>(m);
   init_ref_iterator<LIEF::ELF::it_symbols_version_definition>(m);
diff --git a/doc/sphinx/api/cpp/elf.rst b/doc/sphinx/api/cpp/elf.rst
@@ -211,3 +211,6 @@ Enums
 
 .. doxygenenum:: LIEF::ELF::NOTE_ABIS
    :project: lief
+
+.. doxygenenum:: LIEF::ELF::RELOCATION_PURPOSES
+   :project: lief
diff --git a/doc/sphinx/api/python/elf.rst b/doc/sphinx/api/python/elf.rst
@@ -385,6 +385,15 @@ Note ABIs
   :inherited-members:
   :undoc-members:
 
+Relocation purposes
+~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: lief.ELF.RELOCATION_PURPOSES
+  :members:
+  :inherited-members:
+  :undoc-members:
+
+
 
 
 
diff --git a/include/LIEF/ELF/Binary.hpp b/include/LIEF/ELF/Binary.hpp
@@ -124,12 +124,12 @@ class DLL_PUBLIC Binary : public LIEF::Binary {
     it_const_symbols_version_requirement   get_symbols_version_requirement(void) const;
 
     //! @brief Return dynamic relocations
-    it_relocations                         get_dynamic_relocations(void);
-    it_const_relocations                   get_dynamic_relocations(void) const;
+    it_dynamic_relocations                 get_dynamic_relocations(void);
+    it_const_dynamic_relocations           get_dynamic_relocations(void) const;
 
     //! @brief Return `plt.got` relocations
-    it_relocations                         get_pltgot_relocations(void);
-    it_const_relocations                   get_pltgot_relocations(void) const;
+    it_pltgot_relocations                  get_pltgot_relocations(void);
+    it_const_pltgot_relocations            get_pltgot_relocations(void) const;
 
     //! @brief ``true`` if GNU hash is used
     //!
@@ -411,11 +411,7 @@ class DLL_PUBLIC Binary : public LIEF::Binary {
     //! A list of static symbols
     symbols_t                     static_symbols_;
 
-    //! The binary's dynamic Relocations if any
-    relocations_t                 dynamic_relocations_;
-
-    //! .rela.plt
-    relocations_t                 pltgot_relocations_;
+    relocations_t                 relocations_;
 
     //! .gnu.version
     symbols_version_t             symbol_version_table_;
diff --git a/include/LIEF/ELF/EnumToString.hpp b/include/LIEF/ELF/EnumToString.hpp
@@ -40,6 +40,7 @@ DLL_PUBLIC const char* to_string(OS_ABI e);
 DLL_PUBLIC const char* to_string(DYNSYM_COUNT_METHODS e);
 DLL_PUBLIC const char* to_string(NOTE_TYPES e);
 DLL_PUBLIC const char* to_string(NOTE_ABIS e);
+DLL_PUBLIC const char* to_string(RELOCATION_PURPOSES e);
 } // namespace ELF
 } // namespace LIEF
 
diff --git a/include/LIEF/ELF/Relocation.hpp b/include/LIEF/ELF/Relocation.hpp
@@ -53,6 +53,7 @@ class DLL_PUBLIC Relocation : public Visitable {
     bool     is_rela(void) const;
     bool     is_rel(void) const;
     ARCH architecture(void) const;
+    RELOCATION_PURPOSES purpose(void) const;
 
     //! @brief Return the **bit** size of the value to patch
     uint32_t size(void) const;
@@ -64,6 +65,7 @@ class DLL_PUBLIC Relocation : public Visitable {
     void address(uint64_t address);
     void addend(int64_t addend);
     void type(uint32_t type);
+    void purpose(RELOCATION_PURPOSES purpose);
 
     virtual void accept(Visitor& visitor) const override;
 
@@ -73,12 +75,13 @@ class DLL_PUBLIC Relocation : public Visitable {
     DLL_PUBLIC friend std::ostream& operator<<(std::ostream& os, const Relocation& entry);
 
   private:
-    uint64_t address_;
-    uint32_t type_;
-    int64_t  addend_;
-    bool     isRela_;
-    Symbol*  symbol_;
-    ARCH     architecture_;
+    uint64_t            address_;
+    uint32_t            type_;
+    int64_t             addend_;
+    bool                isRela_;
+    Symbol*             symbol_;
+    ARCH                architecture_;
+    RELOCATION_PURPOSES purpose_;
 };
 
 }
diff --git a/include/LIEF/ELF/enums.inc b/include/LIEF/ELF/enums.inc
@@ -976,3 +976,10 @@ enum NOTE_ABIS {
   ELF_NOTE_OS_SYLLABLE = 5,
 };
 
+enum RELOCATION_PURPOSES {
+  RELOC_PURPOSE_NONE    = 0,
+  RELOC_PURPOSE_PLTGOT  = 1,
+  RELOC_PURPOSE_DYNAMIC = 2,
+  RELOC_PURPOSE_OBJECT  = 3,
+};
+
diff --git a/include/LIEF/ELF/type_traits.hpp b/include/LIEF/ELF/type_traits.hpp
@@ -50,8 +50,12 @@ using it_symbols                               = ref_iterator<symbols_t&>;
 using it_const_symbols                         = const_ref_iterator<const symbols_t&>;
 
 using relocations_t                            = std::vector<Relocation*>;
-using it_relocations                           = ref_iterator<relocations_t&>;
-using it_const_relocations                     = const_ref_iterator<const relocations_t&>;
+
+using it_pltgot_relocations                    = filter_iterator<relocations_t>;
+using it_const_pltgot_relocations              = const_filter_iterator<const relocations_t>;
+
+using it_dynamic_relocations                   = filter_iterator<relocations_t>;
+using it_const_dynamic_relocations             = const_filter_iterator<const relocations_t>;
 
 using symbols_version_t                        = std::vector<SymbolVersion*>;
 using it_symbols_version                       = ref_iterator<symbols_version_t&>;
diff --git a/src/ELF/Binary.cpp b/src/ELF/Binary.cpp
@@ -319,28 +319,35 @@ void Binary::remove_dynamic_symbol(Symbol* symbol) {
 
   // Update relocations
   auto&& it_relocation = std::find_if(
-      std::begin(this->pltgot_relocations_),
-      std::end(this->pltgot_relocations_),
+      std::begin(this->relocations_),
+      std::end(this->relocations_),
       [&symbol] (const Relocation* relocation) {
-        return relocation != nullptr and relocation->has_symbol() and relocation->symbol() == *symbol;
+        return relocation != nullptr and
+        relocation->purpose() == RELOCATION_PURPOSES::RELOC_PURPOSE_PLTGOT and
+        relocation->has_symbol() and
+        relocation->symbol() == *symbol;
       });
 
-  if (it_relocation != std::end(this->pltgot_relocations_)) {
+  if (it_relocation != std::end(this->relocations_)) {
     delete *it_relocation;
-    this->pltgot_relocations_.erase(it_relocation);
+    this->relocations_.erase(it_relocation);
   } else {
   }
 
 
   it_relocation = std::find_if(
-      std::begin(this->dynamic_relocations_),
-      std::end(this->dynamic_relocations_),
+      std::begin(this->relocations_),
+      std::end(this->relocations_),
       [&symbol] (const Relocation* relocation) {
-        return relocation != nullptr and relocation->has_symbol() and relocation->symbol() == *symbol;
+        return relocation != nullptr and
+        relocation->purpose() == RELOCATION_PURPOSES::RELOC_PURPOSE_DYNAMIC and
+        relocation->has_symbol() and
+        relocation->symbol() == *symbol;
       });
-  if (it_relocation != std::end(this->dynamic_relocations_)) {
+
+  if (it_relocation != std::end(this->relocations_)) {
     delete *it_relocation;
-    this->dynamic_relocations_.erase(it_relocation);
+    this->relocations_.erase(it_relocation);
   }
 
   // Update symbol versions
@@ -368,22 +375,40 @@ void Binary::remove_dynamic_symbol(Symbol* symbol) {
 // Dynamics
 // --------
 
-it_relocations Binary::get_dynamic_relocations(void) {
-  return it_relocations{std::ref(this->dynamic_relocations_)};
+it_dynamic_relocations Binary::get_dynamic_relocations(void) {
+  return filter_iterator<relocations_t>{std::ref(this->relocations_),
+    [] (const Relocation* reloc) {
+      return reloc->purpose() == RELOCATION_PURPOSES::RELOC_PURPOSE_DYNAMIC;
+    }
+  };
+
 }
 
-it_const_relocations Binary::get_dynamic_relocations(void) const {
-  return it_const_relocations{std::cref(this->dynamic_relocations_)};
+it_const_dynamic_relocations Binary::get_dynamic_relocations(void) const {
+  return const_filter_iterator<const relocations_t>{std::cref(this->relocations_),
+    [] (const Relocation* reloc) {
+      return reloc->purpose() == RELOCATION_PURPOSES::RELOC_PURPOSE_DYNAMIC;
+    }
+  };
+
 }
 
 // plt/got
 // -------
-it_relocations Binary::get_pltgot_relocations(void) {
-  return it_relocations{std::ref(this->pltgot_relocations_)};
+it_pltgot_relocations Binary::get_pltgot_relocations(void) {
+  return filter_iterator<relocations_t>{std::ref(this->relocations_),
+    [] (const Relocation* reloc) {
+      return reloc->purpose() == RELOCATION_PURPOSES::RELOC_PURPOSE_PLTGOT;
+    }
+  };
 }
 
-it_const_relocations Binary::get_pltgot_relocations(void) const {
-  return it_const_relocations{std::cref(this->pltgot_relocations_)};
+it_const_pltgot_relocations Binary::get_pltgot_relocations(void) const {
+  return const_filter_iterator<const relocations_t>{std::cref(this->relocations_),
+    [] (const Relocation* reloc) {
+      return reloc->purpose() == RELOCATION_PURPOSES::RELOC_PURPOSE_PLTGOT;
+    }
+  };
 }
 
 LIEF::symbols_t Binary::get_abstract_symbols(void) {
@@ -788,18 +813,19 @@ void Binary::patch_address(uint64_t address, uint64_t patch_value, size_t size)
 
 
 void Binary::patch_pltgot(const Symbol& symbol, uint64_t address) {
+  it_pltgot_relocations pltgot_relocations = this->get_pltgot_relocations();
   auto&& it_relocation = std::find_if(
-      std::begin(this->pltgot_relocations_),
-      std::end(this->pltgot_relocations_),
-      [&symbol] (const Relocation* relocation) {
-        return relocation->has_symbol() and relocation->symbol() == symbol;
+      std::begin(pltgot_relocations),
+      std::end(pltgot_relocations),
+      [&symbol] (const Relocation& relocation) {
+        return relocation.has_symbol() and relocation.symbol() == symbol;
       });
 
-  if (it_relocation == std::end(this->pltgot_relocations_)) {
+  if (it_relocation == std::end(pltgot_relocations)) {
     throw not_found("Unable to find the relocation associated with symbol '" + symbol.name() + "'");
   }
 
-  uint64_t got_address = (*it_relocation)->address();
+  uint64_t got_address = (*it_relocation).address();
   this->patch_address(got_address, address, sizeof(uint64_t));
   //(*it_relocation)->address(0);
   //delete *it_relocation;
@@ -1641,12 +1667,7 @@ std::ostream& Binary::print(std::ostream& os) const {
 
 Binary::~Binary(void) {
 
-  for (Relocation* relocation : this->pltgot_relocations_) {
-    delete relocation;
-  }
-
-
-  for (Relocation* relocation : this->dynamic_relocations_) {
+  for (Relocation* relocation : this->relocations_) {
     delete relocation;
   }
 
diff --git a/src/ELF/Builder.tcc b/src/ELF/Builder.tcc
@@ -50,11 +50,11 @@ void Builder::build(void) {
     }
   }
 
-  if (this->binary_->dynamic_relocations_.size() > 0) {
+  if (this->binary_->get_dynamic_relocations().size() > 0) {
     this->build_dynamic_relocations<ELF_T>();
   }
 
-  if (this->binary_->pltgot_relocations_.size() > 0) {
+  if (this->binary_->get_pltgot_relocations().size() > 0) {
     this->build_pltgot_relocations<ELF_T>();
   }
 
@@ -831,12 +831,14 @@ void Builder::build_dynamic_relocations(void) {
   using Elf_Rel    = typename ELF_T::Elf_Rel;
   LOG(DEBUG) << "[+] Building dynamic relocations";
 
-  bool isRela = this->binary_->dynamic_relocations_[0]->is_rela();
+  it_dynamic_relocations dynamic_relocations = this->binary_->get_dynamic_relocations();
+
+  bool isRela = dynamic_relocations[0].is_rela();
   if (not std::all_of(
-        std::begin(this->binary_->dynamic_relocations_),
-        std::end(this->binary_->dynamic_relocations_),
-        [isRela] (const Relocation* relocation) {
-          return relocation != nullptr and relocation->is_rela() == isRela;
+        std::begin(dynamic_relocations),
+        std::end(dynamic_relocations),
+        [isRela] (const Relocation& relocation) {
+          return relocation.is_rela() == isRela;
         })) {
       throw LIEF::type_error("Relocation are not of the same type");
   }
@@ -889,9 +891,9 @@ void Builder::build_dynamic_relocations(void) {
   Section& relocation_section = this->binary_->section_from_virtual_address((*it_dyn_relocation)->value());
 
   if (isRela) {
-    (*it_dyn_relocation_size)->value(this->binary_->dynamic_relocations_.size() * sizeof(Elf_Rela));
+    (*it_dyn_relocation_size)->value(dynamic_relocations.size() * sizeof(Elf_Rela));
   } else {
-    (*it_dyn_relocation_size)->value(this->binary_->dynamic_relocations_.size() * sizeof(Elf_Rel));
+    (*it_dyn_relocation_size)->value(dynamic_relocations.size() * sizeof(Elf_Rel));
   }
 
   std::vector<uint8_t> content;
@@ -961,13 +963,16 @@ void Builder::build_pltgot_relocations(void) {
   using Elf_Rel    = typename ELF_T::Elf_Rel;
 
   LOG(DEBUG) << "[+] Building .plt.got relocations";
-  bool isRela = this->binary_->pltgot_relocations_[0]->is_rela();
+
+  it_pltgot_relocations pltgot_relocations = this->binary_->get_pltgot_relocations();
+
+  bool isRela = pltgot_relocations[0].is_rela();
 
   if (not std::all_of(
-        std::begin(this->binary_->pltgot_relocations_),
-        std::end(this->binary_->pltgot_relocations_),
-        [isRela] (const Relocation* relocation) {
-          return relocation != nullptr and relocation->is_rela() == isRela;
+        std::begin(pltgot_relocations),
+        std::end(pltgot_relocations),
+        [isRela] (const Relocation& relocation) {
+          return relocation.is_rela() == isRela;
         })) {
       throw LIEF::type_error("Relocation are not of the same type");
   }
@@ -999,9 +1004,9 @@ void Builder::build_pltgot_relocations(void) {
 
   Section& relocation_section = this->binary_->section_from_virtual_address((*it_dyn_relocation)->value());
   if (isRela) {
-    (*it_dyn_relocation_size)->value(this->binary_->pltgot_relocations_.size() * sizeof(Elf_Rela));
+    (*it_dyn_relocation_size)->value(pltgot_relocations.size() * sizeof(Elf_Rela));
   } else {
-    (*it_dyn_relocation_size)->value(this->binary_->pltgot_relocations_.size() * sizeof(Elf_Rel));
+    (*it_dyn_relocation_size)->value(pltgot_relocations.size() * sizeof(Elf_Rel));
   }
 
   std::vector<uint8_t> content; // Section's content
diff --git a/src/ELF/EnumToString.cpp b/src/ELF/EnumToString.cpp
diff --git a/src/ELF/Parser.tcc b/src/ELF/Parser.tcc
diff --git a/src/ELF/Relocation.cpp b/src/ELF/Relocation.cpp
diff --git a/tests/elf/test_builder.cpp b/tests/elf/test_builder.cpp
diff --git a/tests/elf/test_parser.cpp b/tests/elf/test_parser.cpp
