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1 // Copyright (c) 2010 The Chromium 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 "net/base/pem_tokenizer.h" | |
6 | |
7 #include "base/base64.h" | |
8 #include "base/string_util.h" | |
9 | |
10 namespace { | |
11 | |
12 const char kPEMSearchBlock[] = "-----BEGIN "; | |
13 const char kPEMBeginBlock[] = "-----BEGIN %s-----"; | |
14 const char kPEMEndBlock[] = "-----END %s-----"; | |
15 | |
16 } // namespace | |
17 | |
18 namespace net { | |
19 | |
20 using base::StringPiece; | |
21 | |
22 PEMTokenizer::PEMTokenizer( | |
23 const StringPiece& str, | |
24 const std::vector<std::string>& allowed_block_types) { | |
25 Init(str, allowed_block_types); | |
26 } | |
27 | |
28 bool PEMTokenizer::GetNext() { | |
29 while (pos_ != StringPiece::npos) { | |
30 // Scan for the beginning of the next PEM encoded block. | |
31 pos_ = str_.find(kPEMSearchBlock, pos_); | |
32 if (pos_ == StringPiece::npos) | |
33 return false; // No more PEM blocks | |
34 | |
35 std::vector<PEMType>::const_iterator it; | |
36 // Check to see if it is of an acceptable block type. | |
37 for (it = block_types_.begin(); it != block_types_.end(); ++it) { | |
38 if (!str_.substr(pos_).starts_with(it->header)) | |
39 continue; | |
40 | |
41 // Look for a footer matching the header. If none is found, then all | |
42 // data following this point is invalid and should not be parsed. | |
43 StringPiece::size_type footer_pos = str_.find(it->footer, pos_); | |
44 if (footer_pos == StringPiece::npos) { | |
45 pos_ = StringPiece::npos; | |
46 return false; | |
47 } | |
48 | |
49 // Chop off the header and footer and parse the data in between. | |
50 StringPiece::size_type data_begin = pos_ + it->header.size(); | |
51 pos_ = footer_pos + it->footer.size(); | |
52 block_type_ = it->type; | |
53 | |
54 StringPiece encoded = str_.substr(data_begin, | |
55 footer_pos - data_begin); | |
56 if (!base::Base64Decode(CollapseWhitespaceASCII(encoded.as_string(), | |
57 true), &data_)) { | |
58 // The most likely cause for a decode failure is a datatype that | |
59 // includes PEM headers, which are not supported. | |
60 break; | |
61 } | |
62 | |
63 return true; | |
64 } | |
65 | |
66 // If the block did not match any acceptable type, move past it and | |
67 // continue the search. Otherwise, |pos_| has been updated to the most | |
68 // appropriate search position to continue searching from and should not | |
69 // be adjusted. | |
70 if (it == block_types_.end()) | |
71 pos_ += sizeof(kPEMSearchBlock); | |
72 } | |
73 | |
74 return false; | |
75 } | |
76 | |
77 void PEMTokenizer::Init( | |
78 const StringPiece& str, | |
79 const std::vector<std::string>& allowed_block_types) { | |
80 str_ = str; | |
81 pos_ = 0; | |
82 | |
83 // Construct PEM header/footer strings for all the accepted types, to | |
84 // reduce parsing later. | |
85 for (std::vector<std::string>::const_iterator it = | |
86 allowed_block_types.begin(); it != allowed_block_types.end(); ++it) { | |
87 PEMType allowed_type; | |
88 allowed_type.type = *it; | |
89 allowed_type.header = StringPrintf(kPEMBeginBlock, it->c_str()); | |
90 allowed_type.footer = StringPrintf(kPEMEndBlock, it->c_str()); | |
91 block_types_.push_back(allowed_type); | |
92 } | |
93 } | |
94 | |
95 } // namespace net | |
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