freenginx-1.27.5

[Maxim Dounin]

Hello!

On Thu, Apr 10, 2025 at 10:15:06PM +0200, A. Schulze via nginx wrote:

> Am 10.04.25 um 07:09 schrieb Maxim Dounin:
> > OTOH, you may try the following patch which tries to use
> > SSL_get0_group_name() and SSL_group_to_name() if available.
> > 
> > Note thought that it slightly changes names as seen in the
> > $ssl_curve and $ssl_curves variables.  In particular, with OpenSSL
> > 3.5 both on the server and as a client, variables are changed
> > from:
> > 
> > $ssl_curve: 0x11ec
> > $ssl_curves: 0x11ec:X25519:prime256v1:X448:secp384r1:secp521r1:ffdhe2048:ffdhe3072
> > 
> > to the following:
> > 
> > $ssl_curve: X25519MLKEM768
> > $ssl_curves: X25519MLKEM768:x25519:secp256r1:x448:secp384r1:secp521r1:ffdhe2048:ffdhe3072
> > 
> > Note "X25519" changed to "x25519", and "prime256v1" to
> > "secp256r1".
> > 
> > Please let me know what do you think.
> 
> Hello Maxim,
> 
> the patch let freenginx use the expected names I personally prefer over hex numbers.
> I don't care if I read X25519 or x25519. I also do not know a scenario, where these names matter.
> But this doesn't mean, they do not exist. If the would exist, an operator may with to
> decide/configure, which names nginx should use.

Thanks for the feedback.

Here is an updated path, which instead uses NIDs as before to 
preserve existing names, and SSL_group_to_name() only if NID is 
not found.  Main benefit of this approach is that names are 
consistent across various SSL libraries, such as different 
versions of OpenSSL and BoringSSL.

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1744560375 -10800
#      Sun Apr 13 19:06:15 2025 +0300
# Node ID e6805fbe81004faafe47d69fb267e4a6b4b0cfbf
# Parent  0a8083b7093e88a56b6b06d534b52c367728d005
SSL: improved handling of $ssl_curve and $ssl_curves variables.

Now both $ssl_curve and $ssl_curves try to use SSL_group_to_name()
if available and no NID is found.  Notably, this makes it possible to
see the name of the X25519MLKEM768 group as supported by OpenSSL 3.5.0.

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -5270,6 +5270,26 @@ ngx_ssl_get_curve(ngx_connection_t *c, n
             return NGX_OK;
         }
 
+#if OPENSSL_VERSION_NUMBER >= 0x30000000L
+        {
+        u_char  *name;
+
+        name = (u_char *) SSL_group_to_name(c->ssl->connection, nid);
+
+        if (name) {
+            s->len = ngx_strlen(name);
+
+            s->data = ngx_pnalloc(pool, s->len);
+            if (s->data == NULL) {
+                return NGX_ERROR;
+            }
+
+            ngx_memcpy(s->data, name, s->len);
+            return NGX_OK;
+        }
+        }
+#endif
+
         s->len = sizeof("0x0000") - 1;
 
         s->data = ngx_pnalloc(pool, s->len);
@@ -5292,10 +5312,13 @@ ngx_ssl_get_curve(ngx_connection_t *c, n
 ngx_int_t
 ngx_ssl_get_curves(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
 {
-#ifdef SSL_CTRL_GET_CURVES
+#ifdef SSL_get1_curves
 
     int         *curves, n, i, nid;
     u_char      *p;
+#if OPENSSL_VERSION_NUMBER >= 0x30000000L
+    u_char      *name;
+#endif
     size_t       len;
 
     n = SSL_get1_curves(c->ssl->connection, NULL);
@@ -5316,12 +5339,25 @@ ngx_ssl_get_curves(ngx_connection_t *c, 
     for (i = 0; i < n; i++) {
         nid = curves[i];
 
-        if (nid & TLSEXT_nid_unknown) {
-            len += sizeof("0x0000") - 1;
-
-        } else {
+        if ((nid & TLSEXT_nid_unknown) == 0) {
             len += ngx_strlen(OBJ_nid2sn(nid));
-        }
+            goto next_length;
+        }
+
+#if OPENSSL_VERSION_NUMBER >= 0x30000000L
+
+        name = (u_char *) SSL_group_to_name(c->ssl->connection, nid);
+
+        if (name) {
+            len += ngx_strlen(name);
+            goto next_length;
+        }
+
+#endif
+
+        len += sizeof("0x0000") - 1;
+
+    next_length:
 
         len += sizeof(":") - 1;
     }
@@ -5336,12 +5372,26 @@ ngx_ssl_get_curves(ngx_connection_t *c, 
     for (i = 0; i < n; i++) {
         nid = curves[i];
 
-        if (nid & TLSEXT_nid_unknown) {
-            p = ngx_sprintf(p, "0x%04xd", nid & 0xffff);
-
-        } else {
+        if ((nid & TLSEXT_nid_unknown) == 0) {
             p = ngx_sprintf(p, "%s", OBJ_nid2sn(nid));
-        }
+            goto next_value;
+
+        }
+
+#if OPENSSL_VERSION_NUMBER >= 0x30000000L
+
+        name = (u_char *) SSL_group_to_name(c->ssl->connection, nid);
+
+        if (name) {
+            p = ngx_sprintf(p, "%s", name);
+            goto next_value;
+        }
+
+#endif
+
+        p = ngx_sprintf(p, "0x%04xd", nid & 0xffff);
+
+    next_value:
 
         *p++ = ':';
     }

-- 
Maxim Dounin
http://mdounin.ru/