From e9247d5150fde23f24225b7f94ff7cac1a89e89f Mon Sep 17 00:00:00 2001
From: Aidan Keefe <aidan.keefe@wolfssl.com>
Date: Thu, 22 Oct 2026 16:33:55 -0600
Subject: [PATCH] Fenrir fixes : ecc.c

Fenrir 9930: harden protocol rules

Updated docs to reflect what was assumed by all tests
---
 doc/dox_comments/header_files/ecc.h | 10 ++++++----
 tests/api/test_ecc.c                |  5 +++++
 wolfcrypt/src/ecc.c                 |  9 +++++++--
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/doc/dox_comments/header_files/ecc.h b/doc/dox_comments/header_files/ecc.h
index 589918da90f..ddc3b6dec65 100644
--- a/doc/dox_comments/header_files/ecc.h
+++ b/doc/dox_comments/header_files/ecc.h
@@ -3405,13 +3405,14 @@ int wc_ecc_set_custom_curve(ecc_key* key, const ecc_set_type* dp);
     \return ecEncCtx pointer on success
     \return NULL on failure
 
-    \param flags Context flags
+    \param flags Either REQ_RESP_CLIENT or REQ_RESP_SERVER; any other
+    value fails and NULL is returned
     \param rng Random number generator
 
     _Example_
     \code
     WC_RNG rng;
-    ecEncCtx* ctx = wc_ecc_ctx_new(0, &rng);
+    ecEncCtx* ctx = wc_ecc_ctx_new(REQ_RESP_CLIENT, &rng);
     \endcode
 
     \sa wc_ecc_ctx_free
@@ -3425,14 +3426,15 @@ ecEncCtx* wc_ecc_ctx_new(int flags, WC_RNG* rng);
     \return ecEncCtx pointer on success
     \return NULL on failure
 
-    \param flags Context flags
+    \param flags Either REQ_RESP_CLIENT or REQ_RESP_SERVER; any other
+    value fails and NULL is returned
     \param rng Random number generator
     \param heap Heap hint
 
     _Example_
     \code
     WC_RNG rng;
-    ecEncCtx* ctx = wc_ecc_ctx_new_ex(0, &rng, NULL);
+    ecEncCtx* ctx = wc_ecc_ctx_new_ex(REQ_RESP_CLIENT, &rng, NULL);
     \endcode
 
     \sa wc_ecc_ctx_new
diff --git a/tests/api/test_ecc.c b/tests/api/test_ecc.c
index b3936ec0545..fe3d3d98800 100644
--- a/tests/api/test_ecc.c
+++ b/tests/api/test_ecc.c
@@ -2121,7 +2121,12 @@ int test_wc_ecc_ctx_new(void)
     /* Test bad args. */
     /* wc_ecc_ctx_new_ex() will free if returned NULL. */
     ExpectNull(cli = wc_ecc_ctx_new(0, &rng));
+    ExpectNull(cli = wc_ecc_ctx_new(100, &rng));
+    ExpectNull(cli = wc_ecc_ctx_new(-3, &rng));
+    /* Must not be truncated to a valid (byte) flag value. */
+    ExpectNull(cli = wc_ecc_ctx_new(REQ_RESP_CLIENT + 256, &rng));
     ExpectNull(cli = wc_ecc_ctx_new(REQ_RESP_CLIENT, NULL));
+    ExpectNull(cli = wc_ecc_ctx_new(REQ_RESP_CLIENT | REQ_RESP_SERVER, &rng));
 
     DoExpectIntEQ(wc_FreeRng(&rng), 0);
     wc_ecc_ctx_free(cli);
diff --git a/wolfcrypt/src/ecc.c b/wolfcrypt/src/ecc.c
index 312753f8008..7455a1340c3 100644
--- a/wolfcrypt/src/ecc.c
+++ b/wolfcrypt/src/ecc.c
@@ -15710,9 +15710,14 @@ int wc_ecc_ctx_reset(ecEncCtx* ctx, WC_RNG* rng)
 ecEncCtx* wc_ecc_ctx_new_ex(int flags, WC_RNG* rng, void* heap)
 {
     int       ret = 0;
-    ecEncCtx* ctx = (ecEncCtx*)XMALLOC(sizeof(ecEncCtx), heap,
-                                                              DYNAMIC_TYPE_ECC);
+    ecEncCtx* ctx;
 
+    if (flags != REQ_RESP_SERVER && flags != REQ_RESP_CLIENT) {
+        WOLFSSL_MSG("Bad flag passed to wc_ecc_ctx_new_ex");
+        return NULL;
+    }
+
+    ctx = (ecEncCtx*)XMALLOC(sizeof(ecEncCtx), heap, DYNAMIC_TYPE_ECC);
     if (ctx) {
         ctx->protocol = (byte)flags;
         ctx->heap     = heap;