From: William Lallemand <wlallemand@haproxy.com>
Date: Thu, 30 Jul 2026 15:56:37 +0000 (+0000)
Subject: BUG/MINOR: ech: reject an ECH store with no usable private key
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=ceb896ab307153e51531bbee8d8a85d7734bca5e;p=thirdparty%2Fhaproxy.git

BUG/MINOR: ech: reject an ECH store with no usable private key

OSSL_ECHSTORE_read_pem() accepts a PEM file containing only an
ECHConfig with no private key. OSSL_ECHSTORE_num_keys() returns 1
on success regardless of the count it writes back, so the existing
"!= 1" check only ever caught the call itself failing, never a
resulting count of zero: a directory containing only such
config-only ".ech" files loaded "successfully" and got installed via
SSL_CTX_set1_echstore(), while unable to decrypt a single
ECH-protected ClientHello, with nothing pointing at the cause.

This should be backported to 3.3 and 3.4.
---

diff --git a/src/ech.c b/src/ech.c
index c62ae1b6c..fdc14ccc6 100644
--- a/src/ech.c
+++ b/src/ech.c
@@ -103,6 +103,11 @@ ignore_entry:
 	}
 	if (OSSL_ECHSTORE_num_keys(es, loaded) != 1)
 		goto end;
+	if (*loaded == 0) {
+		memprintf(err, "%sno ECH key file in '%s' contains a usable private key",
+		          err && *err ? *err : "", dirname);
+		goto end;
+	}
 	if (1 != SSL_CTX_set1_echstore(ctx, es))
 		goto end;
 	rv = 1;