1 // Copyright 2014 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 "components/crx_file/crx_file.h"
6
7 namespace crx_file {
8
9 namespace {
10
11 // The current version of the crx format.
12 static const uint32 kCurrentVersion = 2;
13
14 // The current version of the crx diff format.
15 static const uint32 kCurrentDiffVersion = 0;
16
17 // The maximum size the crx parser will tolerate for a public key.
18 static const uint32 kMaxPublicKeySize = 1 << 16;
19
20 // The maximum size the crx parser will tolerate for a signature.
21 static const uint32 kMaxSignatureSize = 1 << 16;
22
23 } // namespace
24
25 // The magic string embedded in the header.
26 const char kCrxFileHeaderMagic[] = "Cr24";
27 const char kCrxDiffFileHeaderMagic[] = "CrOD";
28
Parse(const CrxFile::Header & header,CrxFile::Error * error)29 scoped_ptr<CrxFile> CrxFile::Parse(const CrxFile::Header& header,
30 CrxFile::Error* error) {
31 if (HeaderIsValid(header, error))
32 return scoped_ptr<CrxFile>(new CrxFile(header));
33 return scoped_ptr<CrxFile>();
34 }
35
Create(const uint32 key_size,const uint32 signature_size,CrxFile::Error * error)36 scoped_ptr<CrxFile> CrxFile::Create(const uint32 key_size,
37 const uint32 signature_size,
38 CrxFile::Error* error) {
39 CrxFile::Header header;
40 memcpy(&header.magic, kCrxFileHeaderMagic, kCrxFileHeaderMagicSize);
41 header.version = kCurrentVersion;
42 header.key_size = key_size;
43 header.signature_size = signature_size;
44 if (HeaderIsValid(header, error))
45 return scoped_ptr<CrxFile>(new CrxFile(header));
46 return scoped_ptr<CrxFile>();
47 }
48
CrxFile(const Header & header)49 CrxFile::CrxFile(const Header& header) : header_(header) {
50 }
51
HeaderIsDelta(const CrxFile::Header & header)52 bool CrxFile::HeaderIsDelta(const CrxFile::Header& header) {
53 return !strncmp(kCrxDiffFileHeaderMagic, header.magic, sizeof(header.magic));
54 }
55
HeaderIsValid(const CrxFile::Header & header,CrxFile::Error * error)56 bool CrxFile::HeaderIsValid(const CrxFile::Header& header,
57 CrxFile::Error* error) {
58 bool valid = false;
59 bool diffCrx = false;
60 if (!strncmp(kCrxDiffFileHeaderMagic, header.magic, sizeof(header.magic)))
61 diffCrx = true;
62 if (strncmp(kCrxFileHeaderMagic, header.magic, sizeof(header.magic)) &&
63 !diffCrx)
64 *error = kWrongMagic;
65 else if (header.version != kCurrentVersion
66 && !(diffCrx && header.version == kCurrentDiffVersion))
67 *error = kInvalidVersion;
68 else if (header.key_size > kMaxPublicKeySize)
69 *error = kInvalidKeyTooLarge;
70 else if (header.key_size == 0)
71 *error = kInvalidKeyTooSmall;
72 else if (header.signature_size > kMaxSignatureSize)
73 *error = kInvalidSignatureTooLarge;
74 else if (header.signature_size == 0)
75 *error = kInvalidSignatureTooSmall;
76 else
77 valid = true;
78 return valid;
79 }
80
81 } // namespace crx_file
82