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