[PATCH 2 of 2] SSL: add $ssl_curve when using AWS-LC

[Piotr Sikora]

# HG changeset patch
# User Piotr Sikora <piotr at aviatrix.com>
# Date 1708977632 0
#      Mon Feb 26 20:00:32 2024 +0000
# Branch patch009
# Node ID dfffc67d286b788204f60701ef4179566d933a1b
# Parent  5e923992006199748e79b08b1e65c4ef41f07495
SSL: add $ssl_curve when using AWS-LC.

Signed-off-by: Piotr Sikora <piotr at aviatrix.com>

diff -r 5e9239920061 -r dfffc67d286b src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c	Mon Feb 26 20:00:30 2024 +0000
+++ b/src/event/ngx_event_openssl.c	Mon Feb 26 20:00:32 2024 +0000
@@ -5163,6 +5163,72 @@
         return NGX_OK;
     }
 
+#elif defined(OPENSSL_IS_AWSLC)
+
+    uint16_t  curve_id;
+
+    curve_id = SSL_get_curve_id(c->ssl->connection);
+
+    /*
+     * Hardcoded table with ANSI / SECG curve names (e.g. "prime256v1"),
+     * which is the same format that OpenSSL returns for $ssl_curve.
+     *
+     * Without this table, we'd need to make 3 additional library calls
+     * to convert from curve_id to ANSI / SECG curve name:
+     *
+     *     nist_name = SSL_get_curve_name(curve_id);
+     *     nid = EC_curve_nist2nid(nist_name);
+     *     ansi_name = OBJ_nid2sn(nid);
+     */
+
+    switch (curve_id) {
+
+#ifdef SSL_CURVE_SECP224R1
+    case SSL_CURVE_SECP224R1:
+        ngx_str_set(s, "secp224r1");
+        return NGX_OK;
+#endif
+
+#ifdef SSL_CURVE_SECP256R1
+    case SSL_CURVE_SECP256R1:
+        ngx_str_set(s, "prime256v1");
+        return NGX_OK;
+#endif
+
+#ifdef SSL_CURVE_SECP384R1
+    case SSL_CURVE_SECP384R1:
+        ngx_str_set(s, "secp384r1");
+        return NGX_OK;
+#endif
+
+#ifdef SSL_CURVE_SECP521R1
+    case SSL_CURVE_SECP521R1:
+        ngx_str_set(s, "secp521r1");
+        return NGX_OK;
+#endif
+
+#ifdef SSL_CURVE_X25519
+    case SSL_CURVE_X25519:
+        ngx_str_set(s, "x25519");
+        return NGX_OK;
+#endif
+
+    case 0:
+        break;
+
+    default:
+        s->len = sizeof("0x0000") - 1;
+
+        s->data = ngx_pnalloc(pool, s->len);
+        if (s->data == NULL) {
+            return NGX_ERROR;
+        }
+
+        ngx_sprintf(s->data, "0x%04xd", curve_id);
+
+        return NGX_OK;
+    }
+
 #endif
 
     ngx_str_null(s);