+
+int proxy_certificate_path(const char *hostname, char *path, size_t size) {
+ int result;
+
+ /* Hostname too long. */
+ if (size - strlen(PROXY_SERVER_CERT_FORMAT) <= strlen(hostname)) {
+ LOG(LOG_WARNING,
+ "proxy_certificate_path(): hostname too long: '%s'",
+ hostname);
+ return -1;
+ }
+ /* Try to prevent path traversals in hostnames. */
+ if (NULL != strstr(hostname, "..")) {
+ LOG(LOG_WARNING,
+ "proxy_certificate_path(): possible path traversal: '%s'",
+ hostname);
+ return -1;
+ }
+ result = snprintf(path, size, PROXY_SERVER_CERT_FORMAT, hostname);
+ if (result < 0) {
+ LOG_PERROR(LOG_ERROR,
+ "proxy_certificate_path(): snprintf failed");
+ return -1;
+ } else if ((size_t)result >= size) {
+ LOG(LOG_ERROR,
+ "proxy_certificate_path(): snprintf buffer too short");
+ return -1;
+ }
+
+ return 0;
+}
+