| 1 | /* |
| 2 | * A git credential helper that interface with Windows' Credential Manager |
| 3 | * |
| 4 | */ |
| 5 | #include <windows.h> |
| 6 | #include <stdio.h> |
| 7 | #include <io.h> |
| 8 | #include <fcntl.h> |
| 9 | #include <wincred.h> |
| 10 | |
| 11 | /* common helpers */ |
| 12 | |
| 13 | #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0])) |
| 14 | |
| 15 | #ifndef _MSC_VER |
| 16 | __attribute__((format (printf, 1, 2))) |
| 17 | #endif |
| 18 | static void die(const char *err, ...) |
| 19 | { |
| 20 | char msg[4096]; |
| 21 | va_list params; |
| 22 | va_start(params, err); |
| 23 | vsnprintf(msg, sizeof(msg), err, params); |
| 24 | fprintf(stderr, "%s\n", msg); |
| 25 | va_end(params); |
| 26 | exit(1); |
| 27 | } |
| 28 | |
| 29 | static void *xmalloc(size_t size) |
| 30 | { |
| 31 | void *ret = malloc(size); |
| 32 | if (!ret && !size) |
| 33 | ret = malloc(1); |
| 34 | if (!ret) |
| 35 | die("Out of memory"); |
| 36 | return ret; |
| 37 | } |
| 38 | |
| 39 | static WCHAR *wusername, *password, *protocol, *host, *path, target[1024], |
| 40 | *password_expiry_utc, *oauth_refresh_token; |
| 41 | |
| 42 | static void target_append(const WCHAR *src) |
| 43 | { |
| 44 | size_t avail = ARRAY_SIZE(target) - wcslen(target) - 1; /* -1 for NUL */ |
| 45 | if (avail < wcslen(src)) |
| 46 | die("target buffer overflow"); |
| 47 | wcsncat(target, src, avail); |
| 48 | } |
| 49 | |
| 50 | static void write_item(const char *what, LPCWSTR wbuf, int wlen) |
| 51 | { |
| 52 | char *buf; |
| 53 | |
| 54 | if (!wbuf || !wlen) { |
| 55 | printf("%s=\n", what); |
| 56 | return; |
| 57 | } |
| 58 | |
| 59 | int len = WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, NULL, 0, NULL, |
| 60 | FALSE); |
| 61 | buf = xmalloc(len); |
| 62 | |
| 63 | if (!WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, buf, len, NULL, FALSE)) |
| 64 | die("WideCharToMultiByte failed!"); |
| 65 | |
| 66 | printf("%s=", what); |
| 67 | fwrite(buf, 1, len, stdout); |
| 68 | putchar('\n'); |
| 69 | free(buf); |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * Match an (optional) expected string and a delimiter in the target string, |
| 74 | * consuming the matched text by updating the target pointer. |
| 75 | */ |
| 76 | |
| 77 | static LPCWSTR wcsstr_last(LPCWSTR str, LPCWSTR find) |
| 78 | { |
| 79 | LPCWSTR res = NULL, pos; |
| 80 | for (pos = wcsstr(str, find); pos; pos = wcsstr(pos + 1, find)) |
| 81 | res = pos; |
| 82 | return res; |
| 83 | } |
| 84 | |
| 85 | static int match_part_with_last(LPCWSTR *ptarget, LPCWSTR want, LPCWSTR delim, int last) |
| 86 | { |
| 87 | LPCWSTR delim_pos, start = *ptarget; |
| 88 | int len; |
| 89 | |
| 90 | /* find start of delimiter (or end-of-string if delim is empty) */ |
| 91 | if (*delim) |
| 92 | delim_pos = last ? wcsstr_last(start, delim) : wcsstr(start, delim); |
| 93 | else |
| 94 | delim_pos = start + wcslen(start); |
| 95 | |
| 96 | /* |
| 97 | * match text up to delimiter, or end of string (e.g. the '/' after |
| 98 | * host is optional if not followed by a path) |
| 99 | */ |
| 100 | if (delim_pos) |
| 101 | len = delim_pos - start; |
| 102 | else |
| 103 | len = wcslen(start); |
| 104 | |
| 105 | /* update ptarget if we either found a delimiter or need a match */ |
| 106 | if (delim_pos || want) |
| 107 | *ptarget = delim_pos ? delim_pos + wcslen(delim) : start + len; |
| 108 | |
| 109 | return !want || (!wcsncmp(want, start, len) && !want[len]); |
| 110 | } |
| 111 | |
| 112 | static int match_part(LPCWSTR *ptarget, LPCWSTR want, LPCWSTR delim) |
| 113 | { |
| 114 | return match_part_with_last(ptarget, want, delim, 0); |
| 115 | } |
| 116 | |
| 117 | static int match_part_last(LPCWSTR *ptarget, LPCWSTR want, LPCWSTR delim) |
| 118 | { |
| 119 | return match_part_with_last(ptarget, want, delim, 1); |
| 120 | } |
| 121 | |
| 122 | static int match_cred_password(const CREDENTIALW *cred) { |
| 123 | int ret; |
| 124 | size_t wlen = cred->CredentialBlobSize / sizeof(WCHAR); |
| 125 | WCHAR *cred_password = xmalloc((wlen + 1) * sizeof(WCHAR)); |
| 126 | wcsncpy_s(cred_password, wlen + 1, |
| 127 | (LPCWSTR)cred->CredentialBlob, wlen); |
| 128 | ret = !wcscmp(cred_password, password); |
| 129 | free(cred_password); |
| 130 | return ret; |
| 131 | } |
| 132 | |
| 133 | static int match_cred(const CREDENTIALW *cred, int match_password) |
| 134 | { |
| 135 | LPCWSTR target = cred->TargetName; |
| 136 | if (wusername && wcscmp(wusername, cred->UserName ? cred->UserName : L"")) |
| 137 | return 0; |
| 138 | |
| 139 | return match_part(&target, L"git", L":") && |
| 140 | match_part(&target, protocol, L"://") && |
| 141 | match_part_last(&target, wusername, L"@") && |
| 142 | match_part(&target, host, L"/") && |
| 143 | match_part(&target, path, L"") && |
| 144 | (!match_password || match_cred_password(cred)); |
| 145 | } |
| 146 | |
| 147 | static void get_credential(void) |
| 148 | { |
| 149 | CREDENTIALW **creds; |
| 150 | DWORD num_creds; |
| 151 | int i; |
| 152 | CREDENTIAL_ATTRIBUTEW *attr; |
| 153 | WCHAR *secret; |
| 154 | WCHAR *line; |
| 155 | WCHAR *remaining_lines; |
| 156 | WCHAR *part; |
| 157 | WCHAR *remaining_parts; |
| 158 | |
| 159 | if (!CredEnumerateW(L"git:*", 0, &num_creds, &creds)) |
| 160 | return; |
| 161 | |
| 162 | /* search for the first credential that matches username */ |
| 163 | for (i = 0; i < num_creds; ++i) |
| 164 | if (match_cred(creds[i], 0)) { |
| 165 | write_item("username", creds[i]->UserName, |
| 166 | creds[i]->UserName ? wcslen(creds[i]->UserName) : 0); |
| 167 | if (creds[i]->CredentialBlobSize > 0) { |
| 168 | secret = xmalloc(creds[i]->CredentialBlobSize + sizeof(WCHAR)); |
| 169 | wcsncpy_s(secret, creds[i]->CredentialBlobSize, (LPCWSTR)creds[i]->CredentialBlob, creds[i]->CredentialBlobSize / sizeof(WCHAR)); |
| 170 | line = wcstok_s(secret, L"\r\n", &remaining_lines); |
| 171 | write_item("password", line, line ? wcslen(line) : 0); |
| 172 | while(line != NULL) { |
| 173 | part = wcstok_s(line, L"=", &remaining_parts); |
| 174 | if (!wcscmp(part, L"oauth_refresh_token")) { |
| 175 | write_item("oauth_refresh_token", remaining_parts, remaining_parts ? wcslen(remaining_parts) : 0); |
| 176 | } |
| 177 | line = wcstok_s(NULL, L"\r\n", &remaining_lines); |
| 178 | } |
| 179 | free(secret); |
| 180 | } else { |
| 181 | write_item("password", |
| 182 | (LPCWSTR)creds[i]->CredentialBlob, |
| 183 | creds[i]->CredentialBlobSize / sizeof(WCHAR)); |
| 184 | } |
| 185 | for (int j = 0; j < creds[i]->AttributeCount; j++) { |
| 186 | attr = creds[i]->Attributes + j; |
| 187 | if (!wcscmp(attr->Keyword, L"git_password_expiry_utc")) { |
| 188 | write_item("password_expiry_utc", (LPCWSTR)attr->Value, |
| 189 | attr->ValueSize / sizeof(WCHAR)); |
| 190 | break; |
| 191 | } |
| 192 | } |
| 193 | break; |
| 194 | } |
| 195 | |
| 196 | CredFree(creds); |
| 197 | } |
| 198 | |
| 199 | static void store_credential(void) |
| 200 | { |
| 201 | CREDENTIALW cred; |
| 202 | CREDENTIAL_ATTRIBUTEW expiry_attr; |
| 203 | WCHAR *secret; |
| 204 | int wlen; |
| 205 | |
| 206 | if (!wusername || !password) |
| 207 | return; |
| 208 | |
| 209 | if (oauth_refresh_token) { |
| 210 | wlen = _scwprintf(L"%s\r\noauth_refresh_token=%s", password, oauth_refresh_token); |
| 211 | secret = xmalloc((wlen + 1) * sizeof(WCHAR)); |
| 212 | _snwprintf_s(secret, wlen + 1, wlen, L"%s\r\noauth_refresh_token=%s", password, oauth_refresh_token); |
| 213 | } else { |
| 214 | secret = _wcsdup(password); |
| 215 | } |
| 216 | |
| 217 | cred.Flags = 0; |
| 218 | cred.Type = CRED_TYPE_GENERIC; |
| 219 | cred.TargetName = target; |
| 220 | cred.Comment = L"saved by git-credential-wincred"; |
| 221 | cred.CredentialBlobSize = wcslen(secret) * sizeof(WCHAR); |
| 222 | cred.CredentialBlob = (LPVOID)_wcsdup(secret); |
| 223 | cred.Persist = CRED_PERSIST_LOCAL_MACHINE; |
| 224 | cred.AttributeCount = 0; |
| 225 | cred.Attributes = NULL; |
| 226 | if (password_expiry_utc != NULL) { |
| 227 | expiry_attr.Keyword = L"git_password_expiry_utc"; |
| 228 | expiry_attr.Value = (LPVOID)password_expiry_utc; |
| 229 | expiry_attr.ValueSize = (wcslen(password_expiry_utc)) * sizeof(WCHAR); |
| 230 | expiry_attr.Flags = 0; |
| 231 | cred.Attributes = &expiry_attr; |
| 232 | cred.AttributeCount = 1; |
| 233 | } |
| 234 | cred.TargetAlias = NULL; |
| 235 | cred.UserName = wusername; |
| 236 | |
| 237 | free(secret); |
| 238 | |
| 239 | if (!CredWriteW(&cred, 0)) |
| 240 | die("CredWrite failed"); |
| 241 | } |
| 242 | |
| 243 | static void erase_credential(void) |
| 244 | { |
| 245 | CREDENTIALW **creds; |
| 246 | DWORD num_creds; |
| 247 | int i; |
| 248 | |
| 249 | if (!CredEnumerateW(L"git:*", 0, &num_creds, &creds)) |
| 250 | return; |
| 251 | |
| 252 | for (i = 0; i < num_creds; ++i) { |
| 253 | if (match_cred(creds[i], password != NULL)) |
| 254 | CredDeleteW(creds[i]->TargetName, creds[i]->Type, 0); |
| 255 | } |
| 256 | |
| 257 | CredFree(creds); |
| 258 | } |
| 259 | |
| 260 | static WCHAR *utf8_to_utf16_dup(const char *str) |
| 261 | { |
| 262 | int wlen = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0); |
| 263 | WCHAR *wstr = xmalloc(sizeof(WCHAR) * wlen); |
| 264 | MultiByteToWideChar(CP_UTF8, 0, str, -1, wstr, wlen); |
| 265 | return wstr; |
| 266 | } |
| 267 | |
| 268 | #define KB (1024) |
| 269 | |
| 270 | static void read_credential(void) |
| 271 | { |
| 272 | size_t alloc = 100 * KB; |
| 273 | char *buf = calloc(alloc, sizeof(*buf)); |
| 274 | |
| 275 | while (fgets(buf, alloc, stdin)) { |
| 276 | char *v; |
| 277 | size_t len = strlen(buf); |
| 278 | int ends_in_newline = 0; |
| 279 | /* strip trailing CR / LF */ |
| 280 | if (len && buf[len - 1] == '\n') { |
| 281 | buf[--len] = 0; |
| 282 | ends_in_newline = 1; |
| 283 | } |
| 284 | if (len && buf[len - 1] == '\r') |
| 285 | buf[--len] = 0; |
| 286 | |
| 287 | if (!ends_in_newline) |
| 288 | die("bad input: %s", buf); |
| 289 | |
| 290 | if (!*buf) |
| 291 | break; |
| 292 | |
| 293 | v = strchr(buf, '='); |
| 294 | if (!v) |
| 295 | die("bad input: %s", buf); |
| 296 | *v++ = '\0'; |
| 297 | |
| 298 | if (!strcmp(buf, "protocol")) |
| 299 | protocol = utf8_to_utf16_dup(v); |
| 300 | else if (!strcmp(buf, "host")) |
| 301 | host = utf8_to_utf16_dup(v); |
| 302 | else if (!strcmp(buf, "path")) |
| 303 | path = utf8_to_utf16_dup(v); |
| 304 | else if (!strcmp(buf, "username")) { |
| 305 | wusername = utf8_to_utf16_dup(v); |
| 306 | } else if (!strcmp(buf, "password")) |
| 307 | password = utf8_to_utf16_dup(v); |
| 308 | else if (!strcmp(buf, "password_expiry_utc")) |
| 309 | password_expiry_utc = utf8_to_utf16_dup(v); |
| 310 | else if (!strcmp(buf, "oauth_refresh_token")) |
| 311 | oauth_refresh_token = utf8_to_utf16_dup(v); |
| 312 | /* |
| 313 | * Ignore other lines; we don't know what they mean, but |
| 314 | * this future-proofs us when later versions of git do |
| 315 | * learn new lines, and the helpers are updated to match. |
| 316 | */ |
| 317 | } |
| 318 | |
| 319 | free(buf); |
| 320 | } |
| 321 | |
| 322 | int main(int argc, char *argv[]) |
| 323 | { |
| 324 | const char *usage = |
| 325 | "usage: git credential-wincred <get|store|erase>\n"; |
| 326 | |
| 327 | if (!argv[1]) |
| 328 | die("%s", usage); |
| 329 | |
| 330 | /* git use binary pipes to avoid CRLF-issues */ |
| 331 | _setmode(_fileno(stdin), _O_BINARY); |
| 332 | _setmode(_fileno(stdout), _O_BINARY); |
| 333 | |
| 334 | read_credential(); |
| 335 | |
| 336 | if (!protocol || !(host || path)) |
| 337 | return 0; |
| 338 | |
| 339 | /* prepare 'target', the unique key for the credential */ |
| 340 | wcscpy(target, L"git:"); |
| 341 | target_append(protocol); |
| 342 | target_append(L"://"); |
| 343 | if (wusername) { |
| 344 | target_append(wusername); |
| 345 | target_append(L"@"); |
| 346 | } |
| 347 | if (host) |
| 348 | target_append(host); |
| 349 | if (path) { |
| 350 | target_append(L"/"); |
| 351 | target_append(path); |
| 352 | } |
| 353 | |
| 354 | if (!strcmp(argv[1], "get")) |
| 355 | get_credential(); |
| 356 | else if (!strcmp(argv[1], "store")) |
| 357 | store_credential(); |
| 358 | else if (!strcmp(argv[1], "erase")) |
| 359 | erase_credential(); |
| 360 | /* otherwise, ignore unknown action */ |
| 361 | return 0; |
| 362 | } |