From 2e00d0bb059dae7f2a099952fda78cd682f5b3e4 Mon Sep 17 00:00:00 2001
From: tb <>
Date: Tue, 9 Jun 2026 05:24:47 +0000
Subject: ecdh: add error codes for point at infinity/not on curve

The point at infinity would previously raise EC_R_POINT_AT_INFINITY via
EC_POINT_get_affine_coordinates(). For consistency, also raise an error
for off-curve points.

pointed out by/ok kenjiro
---
 src/lib/libcrypto/ecdh/ecdh.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

(limited to 'src/lib')

diff --git a/src/lib/libcrypto/ecdh/ecdh.c b/src/lib/libcrypto/ecdh/ecdh.c
index 51b409a5dd..218c584558 100644
--- a/src/lib/libcrypto/ecdh/ecdh.c
+++ b/src/lib/libcrypto/ecdh/ecdh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ecdh.c,v 1.14 2026/06/08 12:08:08 tb Exp $ */
+/* $OpenBSD: ecdh.c,v 1.15 2026/06/09 05:24:47 tb Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -169,11 +169,15 @@ ec_key_ecdh_compute_key(unsigned char **out, size_t *out_len,
 	if ((group = EC_KEY_get0_group(ecdh)) == NULL)
 		goto err;
 
-	if (EC_POINT_is_at_infinity(group, pub_key))
+	if (EC_POINT_is_at_infinity(group, pub_key)) {
+		ECerror(EC_R_POINT_AT_INFINITY);
 		goto err;
+	}
 
-	if (EC_POINT_is_on_curve(group, pub_key, ctx) <= 0)
+	if (EC_POINT_is_on_curve(group, pub_key, ctx) <= 0) {
+		ECerror(EC_R_POINT_IS_NOT_ON_CURVE);
 		goto err;
+	}
 
 	if ((point = EC_POINT_new(group)) == NULL) {
 		ECerror(ERR_R_MALLOC_FAILURE);
-- 
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