+
+int auth_get_data(const char *username, void *data, size_t data_len) {
+ char filename[FILENAME_MAX];
+ int fd;
+ int len = 0;
+
+ if (!valid_name(username))
+ return 0;
+
+ snprintf(filename, FILENAME_MAX, "%s/%s/auth", blergconf.data_path, username);
+ fd = open(filename, O_RDONLY);
+ if (fd == -1)
+ return 0;
+ flock(fd, LOCK_SH);
+ len = read(fd, data, data_len);
+ flock(fd, LOCK_UN);
+ close(fd);
+
+ if (len < 0) {
+ perror("auth_get_data");
+ return 0;
+ } else if (len < data_len) {
+ fprintf(stderr, "Short read getting auth data\n");
+ return 0;
+ }
+
+ return 1;
+}
+
+int auth_check_scrypt(struct auth_v2 *auth, const char *username, const char *password) {
+ unsigned char givenpw[SCRYPT_OUTPUT_SIZE];
+ int r;
+
+ r = crypto_scrypt((const uint8_t *)password, strlen(password), auth->salt, SCRYPT_SALT_SIZE, SCRYPT_N, SCRYPT_r, SCRYPT_p, givenpw, SCRYPT_OUTPUT_SIZE);
+ if (r != 0) {
+ fprintf(stderr, "Failure in scrypt for %s\n", username);
+ return 0;
+ }
+
+ if (memcmp(givenpw, auth->password, SCRYPT_OUTPUT_SIZE) == 0)
+ return 1;
+ else
+ return 0;
+}
+
+int auth_check_password_v1(const char *username, const char *password) {
+ struct auth_v2 auth;
+
+ if (auth_get_password(username, (char *)auth.password) == 0)
+ return 0;
+
+ if (auth_get_salt(username, auth.salt) == 0)
+ return 0;
+
+ return auth_check_scrypt(&auth, username, password);
+}
+
+int auth_check_password_v2(const char *username, const char *password) {
+ struct auth_v2 auth;
+
+ if (auth_get_data(username, (void *) &auth, sizeof(struct auth_v2)) == 0)
+ return 0;
+
+ return auth_check_scrypt(&auth, username, password);
+}
+
+int auth_check_password(const char *username, const char *password) {
+ int version = auth_get_password_version(username);
+
+ switch(version) {
+ case 0:
+ if (auth_check_password_v0(username, password)) {
+ /* Refresh to the newest version */
+ auth_set_password(username, password);
+ return 1;
+ } else {
+ return 0;
+ }
+ break;
+ case 1:
+ if (auth_check_password_v1(username, password)) {
+ /* Refresh to the newest version */
+ auth_set_password(username, password);
+ return 1;
+ } else {
+ return 0;
+ }
+ break;
+ case 2:
+ return auth_check_password_v2(username, password);
+ }
+ fprintf(stderr, "auth_check_password fell through. Bad password version?\n");
+ return 0;
+}
+
+void hexify(char *dst, char *src, int len) {
+ static char hex[] = "0123456789abcdef";
+ int i;
+
+ for (i = 0; i < len; i++) {
+ dst[i * 2] = hex[(src[i] & 0xF0) >> 4];
+ dst[i * 2 + 1] = hex[src[i] & 0xF];
+ }
+}
+
+char *create_random_token() {
+ char buf[TOKEN_SIZE];
+ char *token;
+ int rand_fd;
+
+ rand_fd = open("/dev/urandom", O_RDONLY);
+ if (rand_fd == -1) {
+ perror("Could not open /dev/urandom\n");
+ return 0;
+ }
+ read(rand_fd, buf, TOKEN_SIZE);
+ close(rand_fd);
+
+ token = malloc(TOKEN_SIZE * 2 + 1);
+ hexify(token, buf, TOKEN_SIZE);
+ token[TOKEN_SIZE * 2] = 0;
+
+ return token;
+}
+
+char * auth_login(const char *username, const char *password) {
+ char filename[FILENAME_MAX];
+ struct stringring *sr;
+ char *token;
+
+
+ if (!auth_check_password(username, password))
+ return NULL;
+
+ snprintf(filename, FILENAME_MAX, "%s/%s/tokens", blergconf.data_path, username);
+ sr = stringring_open(filename);
+ if (sr == NULL) {
+ return NULL;
+ }
+ token = create_random_token();
+ if (!stringring_add(sr, token)) {
+ free(token);
+ stringring_close(sr);
+ return NULL;
+ }
+ stringring_close(sr);
+
+ return token;
+}
+
+int auth_logout(const char *username, const char *token) {
+ char filename[FILENAME_MAX];
+ struct stringring *sr;
+ int ret;
+
+ if (!valid_name(username))
+ return 0;
+
+ snprintf(filename, FILENAME_MAX, "%s/%s/tokens", blergconf.data_path, username);
+ if (access(filename, F_OK) != 0) {
+ return 0;
+ }
+ sr = stringring_open(filename);
+ if (sr == NULL) {
+ return 0;
+ }
+ ret = stringring_remove(sr, token);
+ stringring_close(sr);
+
+ return ret;
+}
+
+int auth_check_token(const char *username, const char *given_token) {
+ char filename[FILENAME_MAX];
+ struct stringring *sr;
+ int ret;
+
+ snprintf(filename, FILENAME_MAX, "%s/%s/tokens", blergconf.data_path, username);
+ if (access(filename, F_OK) != 0) {
+ return 0;
+ }
+ sr = stringring_open(filename);
+ if (sr == NULL) {
+ return 0;
+ }
+ ret = (stringring_find(sr, given_token, AUTHENTICATION_TIMEOUT) != -1);
+ if (ret == 1) {
+ /* Update token timestamp */
+ stringring_touch(sr, given_token);
+ }
+ stringring_close(sr);
+
+ return ret;
+}
+
+/* Return a 32-bit integer "counter" that will change when the password is
+ * updated. Used to invalidate password recovery schemes after the password is
+ * updated. Returns the counter in the "counter" argument, and returns
+ * true/false on success/failure. */
+int auth_get_counter(const char *username, uint32_t *counter) {
+ struct auth_v2 auth;
+ struct MD5Context ctx;
+ uint8_t md5hash[MD5_DIGEST_SIZE];
+
+ if (auth_get_data(username, (void *) &auth, sizeof(struct auth_v2)) == 0)
+ return 0;
+
+ /* There's probably going to be some question about using MD5 here.
+ * All I really need is to quickly and repeatably scramble some bits.
+ * MD5 can still do that. */
+ MD5Init(&ctx);
+ MD5Update(&ctx, auth.password, SCRYPT_OUTPUT_SIZE);
+ MD5Update(&ctx, auth.salt, SCRYPT_SALT_SIZE);
+ MD5Final((unsigned char *)md5hash, &ctx);
+
+ *counter = ((uint32_t *)md5hash)[0];
+
+ return 1;
+}