Safely display SNI (just in case)
Thanks to Hubert Kario for pointing this out.
@@ -459,9 +459,17 @@ static int ssl_servername_cb(SSL *s, int *ad, void *arg)
{
tlsextctx *p = (tlsextctx *) arg;
const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
- if (servername != NULL && p->biodebug != NULL)
- BIO_printf(p->biodebug, "Hostname in TLS extension: \"%s\"\n",
- servername);
+
+ if (servername != NULL && p->biodebug != NULL) {
+ const char *cp = servername;
+ unsigned char uc;
+
+ BIO_printf(p->biodebug, "Hostname in TLS extension: \"");
+ while ((uc = *cp++) != 0)
+ BIO_printf(p->biodebug,
+ isascii(uc) && isprint(uc) ? "%c" : "\\x%02x", uc);
+ BIO_printf(p->biodebug, "\"\n");
+ }
if (p->servername == NULL)
return SSL_TLSEXT_ERR_NOACK;
