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,
58 0)) {
59 return FALSE;
60 }
61
62 DWORD dwCount = sizeof(DWORD);
63 if (!CryptGetHashParam(hHash, HP_HASHSIZE, (BYTE *)&hashSize, &dwCount, 0)) {
64 return FALSE;
65 }
66
67 *hash = new BYTE[hashSize];
68 ZeroMemory(*hash, hashSize);
69 if (!CryptGetHashParam(hHash, HP_HASHVAL, *hash, &hashSize, 0)) {
70 return FALSE;
71 }
72
73 if (hHash) {
74 CryptDestroyHash(hHash);
75 }
76
77 if (hProv) {
78 CryptReleaseContext(hProv, 0);
79 }
80
81 return TRUE;
82 }
83
84 /**
85 * Converts a file path into a unique registry location for cert storage
86 *
87 * @param filePath The input file path to get a registry path from
88 * @param registryPath A buffer to write the registry path to, must
89 * be of size in WCHARs MAX_PATH + 1
90 * @return TRUE if successful
91 */
CalculateRegistryPathFromFilePath(const LPCWSTR filePath,LPWSTR registryPath)92 BOOL CalculateRegistryPathFromFilePath(const LPCWSTR filePath,
93 LPWSTR registryPath) {
94 size_t filePathLen = wcslen(filePath);
95 if (!filePathLen) {
96 return FALSE;
97 }
98
99 // If the file path ends in a slash, ignore that character
100 if (filePath[filePathLen - 1] == L'\\' || filePath[filePathLen - 1] == L'/') {
101 filePathLen--;
102 }
103
104 // Copy in the full path into our own buffer.
105 // Copying in the extra slash is OK because we calculate the hash
106 // based on the filePathLen which excludes the slash.
107 // +2 to account for the possibly trailing slash and the null terminator.
108 WCHAR *lowercasePath = new WCHAR[filePathLen + 2];
109 memset(lowercasePath, 0, (filePathLen + 2) * sizeof(WCHAR));
110 wcsncpy(lowercasePath, filePath, filePathLen + 1);
111 _wcslwr(lowercasePath);
112
113 BYTE *hash;
114 DWORD hashSize = 0;
115 if (!CalculateMD5(reinterpret_cast<const char *>(lowercasePath),
116 filePathLen * 2, &hash, hashSize)) {
117 delete[] lowercasePath;
118 return FALSE;
119 }
120 delete[] lowercasePath;
121
122 LPCWSTR baseRegPath =
123 L"SOFTWARE\\Mozilla\\"
124 L"MaintenanceService\\";
125 wcsncpy(registryPath, baseRegPath, MAX_PATH);
126 BinaryDataToHexString(hash, hashSize, registryPath + wcslen(baseRegPath));
127 delete[] hash;
128 return TRUE;
129 }
130