1 // Copyright 2016 The PDFium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include <cstdint>
6
7 #include "core/fpdfapi/parser/cpdf_array.h"
8 #include "core/fpdfapi/parser/cpdf_boolean.h"
9 #include "core/fpdfapi/parser/cpdf_dictionary.h"
10 #include "core/fpdfapi/parser/cpdf_hint_tables.h"
11 #include "core/fpdfapi/parser/cpdf_linearized_header.h"
12 #include "core/fpdfapi/parser/cpdf_number.h"
13 #include "core/fxcrt/cfx_bitstream.h"
14 #include "third_party/base/ptr_util.h"
15
GetData(const int32_t ** data32,const uint8_t ** data,size_t * size)16 int32_t GetData(const int32_t** data32, const uint8_t** data, size_t* size) {
17 const int32_t* ret = *data32;
18 ++(*data32);
19 *data += 4;
20 *size -= 4;
21 return *ret;
22 }
23
24 class HintTableForFuzzing : public CPDF_HintTables {
25 public:
HintTableForFuzzing(CPDF_LinearizedHeader * pLinearized,int shared_hint_table_offset)26 HintTableForFuzzing(CPDF_LinearizedHeader* pLinearized,
27 int shared_hint_table_offset)
28 : CPDF_HintTables(nullptr, pLinearized),
29 shared_hint_table_offset_(shared_hint_table_offset) {}
~HintTableForFuzzing()30 ~HintTableForFuzzing() {}
31
Fuzz(const uint8_t * data,size_t size)32 void Fuzz(const uint8_t* data, size_t size) {
33 if (shared_hint_table_offset_ <= 0)
34 return;
35
36 if (size < static_cast<size_t>(shared_hint_table_offset_))
37 return;
38
39 CFX_BitStream bs(data, size);
40 if (!ReadPageHintTable(&bs))
41 return;
42 ReadSharedObjHintTable(&bs, shared_hint_table_offset_);
43 }
44
45 private:
46 int shared_hint_table_offset_;
47 };
48
49 class FakeLinearized : public CPDF_LinearizedHeader {
50 public:
FakeLinearized(CPDF_Dictionary * linearized_dict)51 explicit FakeLinearized(CPDF_Dictionary* linearized_dict)
52 : CPDF_LinearizedHeader(linearized_dict, 0) {}
53 };
54
LLVMFuzzerTestOneInput(const uint8_t * data,size_t size)55 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
56 // Need 28 bytes for |linearized_dict|.
57 // The header section of page offset hint table is 36 bytes.
58 // The header section of shared object hint table is 24 bytes.
59 if (size < 28 + 36 + 24)
60 return 0;
61
62 const int32_t* data32 = reinterpret_cast<const int32_t*>(data);
63
64 auto linearized_dict = pdfium::MakeUnique<CPDF_Dictionary>();
65 // Set initial value.
66 linearized_dict->SetNewFor<CPDF_Boolean>("Linearized", true);
67 // Set first page end offset
68 linearized_dict->SetNewFor<CPDF_Number>("E", GetData(&data32, &data, &size));
69 // Set page count
70 linearized_dict->SetNewFor<CPDF_Number>("N", GetData(&data32, &data, &size));
71 // Set first page obj num
72 linearized_dict->SetNewFor<CPDF_Number>("O", GetData(&data32, &data, &size));
73 // Set first page no
74 linearized_dict->SetNewFor<CPDF_Number>("P", GetData(&data32, &data, &size));
75
76 auto hint_info = pdfium::MakeUnique<CPDF_Array>();
77 // Add primary hint stream offset
78 hint_info->AddNew<CPDF_Number>(GetData(&data32, &data, &size));
79 // Add primary hint stream size
80 hint_info->AddNew<CPDF_Number>(GetData(&data32, &data, &size));
81 // Set hint stream info.
82 linearized_dict->SetFor("H", std::move(hint_info));
83
84 const int shared_hint_table_offset = GetData(&data32, &data, &size);
85
86 {
87 FakeLinearized linearized(linearized_dict.get());
88 HintTableForFuzzing hint_table(&linearized, shared_hint_table_offset);
89 hint_table.Fuzz(data, size);
90 }
91 return 0;
92 }
93