1    :  // Copyright 2012 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  //
  15    :  // Defines a PE-specific block-graph transform that finds or adds imports to a
  16    :  // given module. Multiple libraries may be specified, and multiple functions per
  17    :  // library. If an import is not found and the mode is kFindOnly, then the
  18    :  // import will be added. This may also cause an entire imported module to
  19    :  // be added.
  20    :  //
  21    :  // Use is as follows:
  22    :  //
  23    :  //   ImportedModule foo_dll("foo.dll");
  24    :  //   size_t foo_foo_index = foo_dll.AddSymbol("foo");
  25    :  //   size_t foo_bar_index = foo_dll.AddSymbol("bar");
  26    :  //
  27    :  //   PEAddImportsTransform add_imports_transform;
  28    :  //   add_imports_transform.AddModule(&foo_dll);
  29    :  //   add_imports_transform.TransformBlockGraph(block_graph, dos_header_block);
  30    :  //
  31    :  //   // Create a reference to function 'bar' in 'foo.dll'.
  32    :  //   BlockGraph::Reference foo_bar_ref;
  33    :  //   CHECK(foo_dll.GetSymbolReference(foo_bar_index, &foo_bar_ref));
  34    :  //   some_block->SetReference(some_offset, foo_bar_ref);
  35    :  //
  36    :  // NOTE: The references provided by GetSymbolReference are only valid
  37    :  //     immediately after they are constructed. If the import directory entries
  38    :  //     are changed between creating the reference and adding it to a block,
  39    :  //     than it may have been invalidated.
  40    :  
  41    :  #ifndef SYZYGY_PE_TRANSFORMS_PE_ADD_IMPORTS_TRANSFORM_H_
  42    :  #define SYZYGY_PE_TRANSFORMS_PE_ADD_IMPORTS_TRANSFORM_H_
  43    :  
  44    :  #include <windows.h>
  45    :  
  46    :  #include "syzygy/block_graph/typed_block.h"
  47    :  #include "syzygy/block_graph/transforms/named_transform.h"
  48    :  #include "syzygy/pe/transforms/pe_coff_add_imports_transform.h"
  49    :  
  50  m :  namespace pe {
  51  m :  namespace transforms {
  52    :  
  53  m :  using block_graph::transforms::NamedBlockGraphTransformImpl;
  54    :  
  55    :  // A transform for adding imported modules/symbols to a given block-graph.
  56  m :  class PEAddImportsTransform
  57  m :      : public NamedBlockGraphTransformImpl<PEAddImportsTransform>,
  58  m :        public PECoffAddImportsTransform {
  59  m :   public:
  60  m :    typedef block_graph::BlockGraph BlockGraph;
  61  m :    typedef block_graph::TransformPolicyInterface TransformPolicyInterface;
  62    :  
  63  m :    PEAddImportsTransform();
  64    :  
  65    :    // Performs the transform. Adds entries for any missing modules and
  66    :    // symbols, returning references to their entries via the ImportedModule
  67    :    // objects.
  68    :    //
  69    :    // If a date/time stamp is specified in an imported module, it will be
  70    :    // used to update the import descriptor binding field (which indicates
  71    :    // which version of the library is currently bound in the import table);
  72    :    // this can be used to provide stubs at program launch time, that will be
  73    :    // replaced by the loader once the real library is loaded.
  74    :    //
  75    :    // @param policy The policy object restricting how the transform is applied.
  76    :    // @param block_graph the BlockGraph to populate.
  77    :    // @param dos_header_block the block containing the module's DOS header.
  78    :    // @returns true on success, false otherwise.
  79  m :    virtual bool TransformBlockGraph(
  80  m :        const TransformPolicyInterface* policy,
  81  m :        BlockGraph* block_graph,
  82  m :        BlockGraph::Block* dos_header_block) override;
  83    :  
  84    :    // @returns a pointer to the Block containing the Image Import Descriptor.
  85  m :    BlockGraph::Block* image_import_descriptor_block() {
  86  m :      return image_import_descriptor_block_;
  87  m :    }
  88    :  
  89    :    // @returns a pointer to the Block containing the Import Address Table.
  90  m :    BlockGraph::Block* import_address_table_block() {
  91  m :      return import_address_table_block_;
  92  m :    }
  93    :  
  94    :    // The name of this transform.
  95  m :    static const char kTransformName[];
  96    :  
  97  m :   protected:
  98    :    // Processes normal imports. If |find_only| is false then this will add the
  99    :    // appropriate PE structures and inject missing imports.
 100  m :    bool FindOrAddImports(bool find_only,
 101  m :                          BlockGraph* block_graph,
 102  m :                          BlockGraph::Block* nt_headers_block);
 103    :    // Processes delay-load imports. This only searches for existing ones, and
 104    :    // currently does not add any new delay-load imports or related PE structures.
 105  m :    bool FindDelayLoadImports(BlockGraph* block_graph,
 106  m :                              BlockGraph::Block* nt_headers_block);
 107    :  
 108    :    // We cache various blocks for easier unittesting.
 109  m :    BlockGraph::Block* image_import_descriptor_block_;
 110  m :    BlockGraph::Block* import_address_table_block_;
 111  m :    BlockGraph::Block* image_delayload_descriptor_block_;
 112  m :  };
 113    :  
 114  m :  }  // namespace transforms
 115  m :  }  // namespace pe
 116    :  
 117    :  #endif  // SYZYGY_PE_TRANSFORMS_PE_ADD_IMPORTS_TRANSFORM_H_