From d5ab205c28468fb99fc1f15fe8ca545d7deecc84 Mon Sep 17 00:00:00 2001
From: Yosuke Shimizu <yosuke@wolfssl.com>
Date: Thu, 17 Sep 2026 13:37:13 +0900
Subject: [PATCH] scep: advertise cipher capabilities the server can actually
 honour

- scep_server.c defines SCEP_SRV_CIPHER_CAP and SCEP_SRV_STD_CAP
  alongside SCEP_SRV_ENC_OID: AES plus SCEPStandard under
  WOLFSSL_AES_128 && HAVE_AES_CBC, and DES3 with no SCEPStandard
  on the 3DES branch.
- handle_get_ca_caps() builds both GetCACaps bodies from those two
  macros in place of the literal AES and SCEPStandard lines.
- test_scep_roundtrip reads the server's rendered capability list
  back, asserting caps.aes and caps.scep_standard against the same
  two macros and caps.renewal unconditionally.

Issue: F-8023
---
 src/scep/scep_server.c                  | 21 ++++++++++++---------
 tests/integration/test_scep_roundtrip.c |  9 +++++++++
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/src/scep/scep_server.c b/src/scep/scep_server.c
index 3458bf7..2a887bf 100644
--- a/src/scep/scep_server.c
+++ b/src/scep/scep_server.c
@@ -45,14 +45,16 @@
 #include <sys/socket.h>
 #include <unistd.h>
 
-/* Content-encryption cipher the CertRep EnvelopedData carries. Mirrors the
- * client's AUTO choice: RFC 8894 section 3.5.2's "AES" capability names
- * AES-128-CBC and nothing else, with the mandatory-to-implement triple DES-CBC
- * as the fallback for a wolfSSL that cannot do AES-128. */
+/* Content-encryption cipher for the CertRep and its GetCACaps tokens. RFC 8894
+ * section 3.5.2: "AES" names AES128-CBC, and "SCEPStandard" implies "AES". */
 #if defined(WOLFSSL_AES_128) && defined(HAVE_AES_CBC)
-    #define SCEP_SRV_ENC_OID AES128CBCb
+    #define SCEP_SRV_ENC_OID    AES128CBCb
+    #define SCEP_SRV_CIPHER_CAP "AES\r\n"
+    #define SCEP_SRV_STD_CAP    "SCEPStandard\r\n"
 #elif !defined(NO_DES3)
-    #define SCEP_SRV_ENC_OID DES3b
+    #define SCEP_SRV_ENC_OID    DES3b
+    #define SCEP_SRV_CIPHER_CAP "DES3\r\n"
+    #define SCEP_SRV_STD_CAP    ""
 #else
     #error "wolfCert's SCEP test server needs AES-128-CBC or 3DES-CBC; rebuild wolfSSL with one of them, or configure without the test server"
 #endif
@@ -304,12 +306,13 @@ static void handle_get_ca_caps(WolfCertServer* s, int fd)
 {
     if (s->cfg.scep_enable_next_ca) {
         send_text(s, fd, 200, "OK", "text/plain",
-                  "POSTPKIOperation\r\nSHA-256\r\nAES\r\nRenewal\r\n"
-                  "SCEPStandard\r\nGetNextCACert\r\n");
+                  "POSTPKIOperation\r\nSHA-256\r\n" SCEP_SRV_CIPHER_CAP
+                  "Renewal\r\n" SCEP_SRV_STD_CAP "GetNextCACert\r\n");
     }
     else {
         send_text(s, fd, 200, "OK", "text/plain",
-                  "POSTPKIOperation\r\nSHA-256\r\nAES\r\nRenewal\r\nSCEPStandard\r\n");
+                  "POSTPKIOperation\r\nSHA-256\r\n" SCEP_SRV_CIPHER_CAP
+                  "Renewal\r\n" SCEP_SRV_STD_CAP);
     }
 }
 
diff --git a/tests/integration/test_scep_roundtrip.c b/tests/integration/test_scep_roundtrip.c
index a31a933..177bc0f 100644
--- a/tests/integration/test_scep_roundtrip.c
+++ b/tests/integration/test_scep_roundtrip.c
@@ -1135,6 +1135,15 @@ int main(void)
     REQUIRE(caps.post_pki_operation);
     REQUIRE(caps.sha256);
 
+#if defined(WOLFSSL_AES_128) && defined(HAVE_AES_CBC)
+    REQUIRE(caps.aes == 1);
+    REQUIRE(caps.scep_standard == 1);
+#else
+    REQUIRE(caps.aes == 0);
+    REQUIRE(caps.scep_standard == 0);
+#endif
+    REQUIRE(caps.renewal);
+
     WolfCertBuffer ca_pem = { 0 };
     REQUIRE(wolfcert_scep_get_ca_cert(&cli, &ca_pem) == WOLFCERT_OK);
     DerBuffer* ca_der = NULL;