name : git-credential-wincred.c /* * A git credential helper that interface with Windows' Credential Manager * */ #include <windows.h> #include <stdio.h> #include <io.h> #include <fcntl.h> #include <wincred.h> /* common helpers */ #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0])) __attribute__((format (printf, 1, 2))) static void die(const char *err, ...) { char msg[4096]; va_list params; va_start(params, err); vsnprintf(msg, sizeof(msg), err, params); fprintf(stderr, "%s\n", msg); va_end(params); exit(1); } static void *xmalloc(size_t size) { void *ret = malloc(size); if (!ret && !size) ret = malloc(1); if (!ret) die("Out of memory"); return ret; } static WCHAR *wusername, *password, *protocol, *host, *path, target[1024], *password_expiry_utc; static void target_append(const WCHAR *src) { size_t avail = ARRAY_SIZE(target) - wcslen(target) - 1; /* -1 for NUL */ if (avail < wcslen(src)) die("target buffer overflow"); wcsncat(target, src, avail); } static void write_item(const char *what, LPCWSTR wbuf, int wlen) { char *buf; if (!wbuf || !wlen) { printf("%s=\n", what); return; } int len = WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, NULL, 0, NULL, FALSE); buf = xmalloc(len); if (!WideCharToMultiByte(CP_UTF8, 0, wbuf, wlen, buf, len, NULL, FALSE)) die("WideCharToMultiByte failed!"); printf("%s=", what); fwrite(buf, 1, len, stdout); putchar('\n'); free(buf); } /* * Match an (optional) expected string and a delimiter in the target string, * consuming the matched text by updating the target pointer. */ static LPCWSTR wcsstr_last(LPCWSTR str, LPCWSTR find) { LPCWSTR res = NULL, pos; for (pos = wcsstr(str, find); pos; pos = wcsstr(pos + 1, find)) res = pos; return res; } static int match_part_with_last(LPCWSTR *ptarget, LPCWSTR want, LPCWSTR delim, int last) { LPCWSTR delim_pos, start = *ptarget; int len; /* find start of delimiter (or end-of-string if delim is empty) */ if (*delim) delim_pos = last ? wcsstr_last(start, delim) : wcsstr(start, delim); else delim_pos = start + wcslen(start); /* * match text up to delimiter, or end of string (e.g. the '/' after * host is optional if not followed by a path) */ if (delim_pos) len = delim_pos - start; else len = wcslen(start); /* update ptarget if we either found a delimiter or need a match */ if (delim_pos || want) *ptarget = delim_pos ? delim_pos + wcslen(delim) : start + len; return !want || (!wcsncmp(want, start, len) && !want[len]); } static int match_part(LPCWSTR *ptarget, LPCWSTR want, LPCWSTR delim) { return match_part_with_last(ptarget, want, delim, 0); } static int match_part_last(LPCWSTR *ptarget, LPCWSTR want, LPCWSTR delim) { return match_part_with_last(ptarget, want, delim, 1); } static int match_cred_password(const CREDENTIALW *cred) { int ret; WCHAR *cred_password = xmalloc(cred->CredentialBlobSize); wcsncpy_s(cred_password, cred->CredentialBlobSize, (LPCWSTR)cred->CredentialBlob, cred->CredentialBlobSize / sizeof(WCHAR)); ret = !wcscmp(cred_password, password); free(cred_password); return ret; } static int match_cred(const CREDENTIALW *cred, int match_password) { LPCWSTR target = cred->TargetName; if (wusername && wcscmp(wusername, cred->UserName ? cred->UserName : L"")) return 0; return match_part(&target, L"git", L":") && match_part(&target, protocol, L"://") && match_part_last(&target, wusername, L"@") && match_part(&target, host, L"/") && match_part(&target, path, L"") && (!match_password || match_cred_password(cred)); } static void get_credential(void) { CREDENTIALW **creds; DWORD num_creds; int i; CREDENTIAL_ATTRIBUTEW *attr; if (!CredEnumerateW(L"git:*", 0, &num_creds, &creds)) return; /* search for the first credential that matches username */ for (i = 0; i < num_creds; ++i) if (match_cred(creds[i], 0)) { write_item("username", creds[i]->UserName, creds[i]->UserName ? wcslen(creds[i]->UserName) : 0); write_item("password", (LPCWSTR)creds[i]->CredentialBlob, creds[i]->CredentialBlobSize / sizeof(WCHAR)); for (int j = 0; j < creds[i]->AttributeCount; j++) { attr = creds[i]->Attributes + j; if (!wcscmp(attr->Keyword, L"git_password_expiry_utc")) { write_item("password_expiry_utc", (LPCWSTR)attr->Value, attr->ValueSize / sizeof(WCHAR)); break; } } break; } CredFree(creds); } static void store_credential(void) { CREDENTIALW cred; CREDENTIAL_ATTRIBUTEW expiry_attr; if (!wusername || !password) return; cred.Flags = 0; cred.Type = CRED_TYPE_GENERIC; cred.TargetName = target; cred.Comment = L"saved by git-credential-wincred"; cred.CredentialBlobSize = (wcslen(password)) * sizeof(WCHAR); cred.CredentialBlob = (LPVOID)password; cred.Persist = CRED_PERSIST_LOCAL_MACHINE; cred.AttributeCount = 0; cred.Attributes = NULL; if (password_expiry_utc != NULL) { expiry_attr.Keyword = L"git_password_expiry_utc"; expiry_attr.Value = (LPVOID)password_expiry_utc; expiry_attr.ValueSize = (wcslen(password_expiry_utc)) * sizeof(WCHAR); expiry_attr.Flags = 0; cred.Attributes = &expiry_attr; cred.AttributeCount = 1; } cred.TargetAlias = NULL; cred.UserName = wusername; if (!CredWriteW(&cred, 0)) die("CredWrite failed"); } static void erase_credential(void) { CREDENTIALW **creds; DWORD num_creds; int i; if (!CredEnumerateW(L"git:*", 0, &num_creds, &creds)) return; for (i = 0; i < num_creds; ++i) { if (match_cred(creds[i], password != NULL)) CredDeleteW(creds[i]->TargetName, creds[i]->Type, 0); } CredFree(creds); } static WCHAR *utf8_to_utf16_dup(const char *str) { int wlen = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0); WCHAR *wstr = xmalloc(sizeof(WCHAR) * wlen); MultiByteToWideChar(CP_UTF8, 0, str, -1, wstr, wlen); return wstr; } #define KB (1024) static void read_credential(void) { size_t alloc = 100 * KB; char *buf = calloc(alloc, sizeof(*buf)); while (fgets(buf, alloc, stdin)) { char *v; size_t len = strlen(buf); int ends_in_newline = 0; /* strip trailing CR / LF */ if (len && buf[len - 1] == '\n') { buf[--len] = 0; ends_in_newline = 1; } if (len && buf[len - 1] == '\r') buf[--len] = 0; if (!ends_in_newline) die("bad input: %s", buf); if (!*buf) break; v = strchr(buf, '='); if (!v) die("bad input: %s", buf); *v++ = '\0'; if (!strcmp(buf, "protocol")) protocol = utf8_to_utf16_dup(v); else if (!strcmp(buf, "host")) host = utf8_to_utf16_dup(v); else if (!strcmp(buf, "path")) path = utf8_to_utf16_dup(v); else if (!strcmp(buf, "username")) { wusername = utf8_to_utf16_dup(v); } else if (!strcmp(buf, "password")) password = utf8_to_utf16_dup(v); else if (!strcmp(buf, "password_expiry_utc")) password_expiry_utc = utf8_to_utf16_dup(v); /* * Ignore other lines; we don't know what they mean, but * this future-proofs us when later versions of git do * learn new lines, and the helpers are updated to match. */ } free(buf); } int main(int argc, char *argv[]) { const char *usage = "usage: git credential-wincred <get|store|erase>\n"; if (!argv[1]) die("%s", usage); /* git use binary pipes to avoid CRLF-issues */ _setmode(_fileno(stdin), _O_BINARY); _setmode(_fileno(stdout), _O_BINARY); read_credential(); if (!protocol || !(host || path)) return 0; /* prepare 'target', the unique key for the credential */ wcscpy(target, L"git:"); target_append(protocol); target_append(L"://"); if (wusername) { target_append(wusername); target_append(L"@"); } if (host) target_append(host); if (path) { target_append(L"/"); target_append(path); } if (!strcmp(argv[1], "get")) get_credential(); else if (!strcmp(argv[1], "store")) store_credential(); else if (!strcmp(argv[1], "erase")) erase_credential(); /* otherwise, ignore unknown action */ return 0; }