1 /* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
4
5 #include <windows.h>
6 #include <wincrypt.h>
7 #include "pathhash.h"
8
9
10 /**
11 * Converts a binary sequence into a hex string
12 *
13 * @param hash The binary data sequence
14 * @param hashSize The size of the binary data sequence
15 * @param hexString A buffer to store the hex string, must be of
16 * size 2 * @hashSize
17 */
18 static void
BinaryDataToHexString(const BYTE * hash,DWORD & hashSize,LPWSTR hexString)19 BinaryDataToHexString(const BYTE *hash, DWORD &hashSize,
20 LPWSTR hexString)
21 {
22 WCHAR *p = hexString;
23 for (DWORD i = 0; i < hashSize; ++i) {
24 wsprintfW(p, L"%.2x", hash[i]);
25 p += 2;
26 }
27 }
28
29 /**
30 * Calculates an MD5 hash for the given input binary data
31 *
32 * @param data Any sequence of bytes
33 * @param dataSize The number of bytes inside @data
34 * @param hash Output buffer to store hash, must be freed by the caller
35 * @param hashSize The number of bytes in the output buffer
36 * @return TRUE on success
37 */
38 static BOOL
CalculateMD5(const char * data,DWORD dataSize,BYTE ** hash,DWORD & hashSize)39 CalculateMD5(const char *data, DWORD dataSize,
40 BYTE **hash, DWORD &hashSize)
41 {
42 HCRYPTPROV hProv = 0;
43 HCRYPTHASH hHash = 0;
44
45 if (!CryptAcquireContext(&hProv, nullptr, nullptr, PROV_RSA_FULL,
46 CRYPT_VERIFYCONTEXT)) {
47 if (NTE_BAD_KEYSET != GetLastError()) {
48 return FALSE;
49 }
50
51 // Maybe it doesn't exist, try to create it.
52 if (!CryptAcquireContext(&hProv, nullptr, nullptr, PROV_RSA_FULL,
53 CRYPT_VERIFYCONTEXT | CRYPT_NEWKEYSET)) {
54 return FALSE;
55 }
56 }
57
58 if (!CryptCreateHash(hProv, CALG_MD5, 0, 0, &hHash)) {
59 return FALSE;
60 }
61
62 if (!CryptHashData(hHash, reinterpret_cast<const BYTE*>(data),
63 dataSize, 0)) {
64 return FALSE;
65 }
66
67 DWORD dwCount = sizeof(DWORD);
68 if (!CryptGetHashParam(hHash, HP_HASHSIZE, (BYTE *)&hashSize,
69 &dwCount, 0)) {
70 return FALSE;
71 }
72
73 *hash = new BYTE[hashSize];
74 ZeroMemory(*hash, hashSize);
75 if (!CryptGetHashParam(hHash, HP_HASHVAL, *hash, &hashSize, 0)) {
76 return FALSE;
77 }
78
79 if (hHash) {
80 CryptDestroyHash(hHash);
81 }
82
83 if (hProv) {
84 CryptReleaseContext(hProv,0);
85 }
86
87 return TRUE;
88 }
89
90 /**
91 * Converts a file path into a unique registry location for cert storage
92 *
93 * @param filePath The input file path to get a registry path from
94 * @param registryPath A buffer to write the registry path to, must
95 * be of size in WCHARs MAX_PATH + 1
96 * @return TRUE if successful
97 */
98 BOOL
CalculateRegistryPathFromFilePath(const LPCWSTR filePath,LPWSTR registryPath)99 CalculateRegistryPathFromFilePath(const LPCWSTR filePath,
100 LPWSTR registryPath)
101 {
102 size_t filePathLen = wcslen(filePath);
103 if (!filePathLen) {
104 return FALSE;
105 }
106
107 // If the file path ends in a slash, ignore that character
108 if (filePath[filePathLen -1] == L'\\' ||
109 filePath[filePathLen - 1] == L'/') {
110 filePathLen--;
111 }
112
113 // Copy in the full path into our own buffer.
114 // Copying in the extra slash is OK because we calculate the hash
115 // based on the filePathLen which excludes the slash.
116 // +2 to account for the possibly trailing slash and the null terminator.
117 WCHAR *lowercasePath = new WCHAR[filePathLen + 2];
118 memset(lowercasePath, 0, (filePathLen + 2) * sizeof(WCHAR));
119 wcsncpy(lowercasePath, filePath, filePathLen + 1);
120 _wcslwr(lowercasePath);
121
122 BYTE *hash;
123 DWORD hashSize = 0;
124 if (!CalculateMD5(reinterpret_cast<const char*>(lowercasePath),
125 filePathLen * 2,
126 &hash, hashSize)) {
127 delete[] lowercasePath;
128 return FALSE;
129 }
130 delete[] lowercasePath;
131
132 LPCWSTR baseRegPath = L"SOFTWARE\\Mozilla\\"
133 L"MaintenanceService\\";
134 wcsncpy(registryPath, baseRegPath, MAX_PATH);
135 BinaryDataToHexString(hash, hashSize,
136 registryPath + wcslen(baseRegPath));
137 delete[] hash;
138 return TRUE;
139 }
140