nss: fix max-tls to be 1.3/1.2

[bagder]

Uh, the default value that is!

Fixes #3261

[kdudka]

Did you test it? If I read the code correctly, the proposed change is a no-op. libcurl on top of NSS defaults to NSS' default min/max versions of TLS.

There seems to be one place that needs to be updated for the --tlsv1 option to work with TLS 1.3 but it will have no effect on --tlsv1.2:

https://github.com/curl/curl/blob/42fd2350/lib/vtls/nss.c#L1642

[bagder]

Did you test it?

Yeps. Before my patch: curl fails as #3261 describes. After patch: that command line works...

the proposed change is a no-op

I beg to differ. The non-patch version sets 1.0 to be the max version by default here:

curl/lib/vtls/nss.c

Line 1795 in 42fd235

SSL_LIBRARY_VERSION_TLS_1_0 /* max */

... so when we raise the minimum to 1.2 with the option, the call to SSL_VersionRangeSet will fail since it asks for minimum 1.2, maximum 1.0:

curl/lib/vtls/nss.c

Line 1844 in 42fd235

if(SSL_VersionRangeSet(model, &sslver) != SECSuccess)

If you have a better/more appropriate fix, I'll happily accept that! =)

[kdudka]

Sorry, I overlooked commit 2e5651a which had actually triggered this bug (allowing to set max < min). Your patch indeed fixes it!

The code I was talking about is actually dead code now and it can be safely removed:

--- a/lib/vtls/nss.c
+++ b/lib/vtls/nss.c
@@ -1638,17 +1638,6 @@ static CURLcode nss_load_ca_certificates(struct connectdata *conn,
 static CURLcode nss_sslver_from_curl(PRUint16 *nssver, long version)
 {
   switch(version) {
-  case CURL_SSLVERSION_TLSv1:
-    /* TODO: set sslver->max to SSL_LIBRARY_VERSION_TLS_1_3 once stable */
-#ifdef SSL_LIBRARY_VERSION_TLS_1_2
-    *nssver = SSL_LIBRARY_VERSION_TLS_1_2;
-#elif defined SSL_LIBRARY_VERSION_TLS_1_1
-    *nssver = SSL_LIBRARY_VERSION_TLS_1_1;
-#else
-    *nssver = SSL_LIBRARY_VERSION_TLS_1_0;
-#endif
-    return CURLE_OK;
-
   case CURL_SSLVERSION_SSLv2:
     *nssver = SSL_LIBRARY_VERSION_2;
     return CURLE_OK;
@@ -1709,10 +1698,8 @@ static CURLcode nss_init_sslver(SSLVersionRange *sslver,
   }

   switch(min) {
-  case CURL_SSLVERSION_DEFAULT:
-    break;
   case CURL_SSLVERSION_TLSv1:
-    sslver->min = SSL_LIBRARY_VERSION_TLS_1_0;
+  case CURL_SSLVERSION_DEFAULT:
     break;
   default:
     result = nss_sslver_from_curl(&sslver->min, min);

[bagder]

Thanks @kdudka, rebased and committed your patch in the branch.

[kdudka]

Looks good!