From nobody Mon Feb 9 10:32:46 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1645099199823456.4688479278344; Thu, 17 Feb 2022 03:59:59 -0800 (PST) Received: from localhost ([::1]:52416 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nKfS2-000665-JV for importer@patchew.org; Thu, 17 Feb 2022 06:59:58 -0500 Received: from eggs.gnu.org ([209.51.188.92]:39168) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nKfPp-00036Y-20 for qemu-devel@nongnu.org; Thu, 17 Feb 2022 06:57:41 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:57506) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nKfPn-00011n-E6 for qemu-devel@nongnu.org; Thu, 17 Feb 2022 06:57:40 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-389-_h_zCT_6PCaS4vOdPN5Dvw-1; Thu, 17 Feb 2022 06:57:37 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A054F1F2DB; Thu, 17 Feb 2022 11:57:36 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.33.36.132]) by smtp.corp.redhat.com (Postfix) with ESMTP id AE18B108648F; Thu, 17 Feb 2022 11:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645099058; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jrVpYs8lGzNh+QkC+LzegzMdgsdDAN4YMxzKWVHaI34=; b=Q9t606AYtTxJ11JbBo3zAYXCUyNauViPJvrJw3eSlVDXSvxL377ZETjpLD4x52IY2MZT6z 7CCOYtluuY/zHdBxkrOQOpgHNU89X6qkwjGJHdVh5gs7O8qBMISP4cxFR2OseU/pBZVEpx bIbw+Xnt/n5WUOVrgvbEbHVEnBh5Khg= X-MC-Unique: _h_zCT_6PCaS4vOdPN5Dvw-1 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Subject: [PULL 03/10] block: print the server key type and fingerprint on failure Date: Thu, 17 Feb 2022 11:57:16 +0000 Message-Id: <20220217115723.1782616-4-berrange@redhat.com> In-Reply-To: <20220217115723.1782616-1-berrange@redhat.com> References: <20220217115723.1782616-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.083, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , qemu-block@nongnu.org, Kashyap Chamarthy , "Richard W.M. Jones" , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Hanna Reitz , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1645099207475100001 When validating the server key fingerprint fails, it is difficult for the user to know what they got wrong. The fingerprint accepted by QEMU is received in a different format than OpenSSH displays. There can also be keys for multiple different ciphers in known_hosts. It may not be obvious which cipher QEMU will use and whether it will be the same as OpenSSH. Address this by printing the server key type and its corresponding fingerprint in the format QEMU accepts. Reviewed-by: Hanna Reitz Reviewed-by: Philippe Mathieu-Daud=C3=A9 Signed-off-by: Daniel P. Berrang=C3=A9 --- block/ssh.c | 37 ++++++++++++++++++++++++++++++------- 1 file changed, 30 insertions(+), 7 deletions(-) diff --git a/block/ssh.c b/block/ssh.c index ac01301409..a64db146db 100644 --- a/block/ssh.c +++ b/block/ssh.c @@ -386,14 +386,28 @@ static int compare_fingerprint(const unsigned char *f= ingerprint, size_t len, return *host_key_check - '\0'; } =20 +static char *format_fingerprint(const unsigned char *fingerprint, size_t l= en) +{ + static const char *hex =3D "0123456789abcdef"; + char *ret =3D g_new0(char, (len * 2) + 1); + for (size_t i =3D 0; i < len; i++) { + ret[i * 2] =3D hex[((fingerprint[i] >> 4) & 0xf)]; + ret[(i * 2) + 1] =3D hex[(fingerprint[i] & 0xf)]; + } + ret[len * 2] =3D '\0'; + return ret; +} + static int check_host_key_hash(BDRVSSHState *s, const char *hash, - enum ssh_publickey_hash_type type, Error **errp) + enum ssh_publickey_hash_type type, const char *typestr, + Error **errp) { int r; ssh_key pubkey; unsigned char *server_hash; size_t server_hash_len; + const char *keytype; =20 r =3D ssh_get_server_publickey(s->session, &pubkey); if (r !=3D SSH_OK) { @@ -401,6 +415,8 @@ check_host_key_hash(BDRVSSHState *s, const char *hash, return -EINVAL; } =20 + keytype =3D ssh_key_type_to_char(ssh_key_type(pubkey)); + r =3D ssh_get_publickey_hash(pubkey, type, &server_hash, &server_hash_= len); ssh_key_free(pubkey); if (r !=3D 0) { @@ -410,12 +426,16 @@ check_host_key_hash(BDRVSSHState *s, const char *hash, } =20 r =3D compare_fingerprint(server_hash, server_hash_len, hash); - ssh_clean_pubkey_hash(&server_hash); if (r !=3D 0) { - error_setg(errp, "remote host key does not match host_key_check '%= s'", - hash); + g_autofree char *server_fp =3D format_fingerprint(server_hash, + server_hash_len); + error_setg(errp, "remote host %s key fingerprint '%s:%s' " + "does not match host_key_check '%s:%s'", + keytype, typestr, server_fp, typestr, hash); + ssh_clean_pubkey_hash(&server_hash); return -EPERM; } + ssh_clean_pubkey_hash(&server_hash); =20 return 0; } @@ -436,13 +456,16 @@ static int check_host_key(BDRVSSHState *s, SshHostKey= Check *hkc, Error **errp) case SSH_HOST_KEY_CHECK_MODE_HASH: if (hkc->u.hash.type =3D=3D SSH_HOST_KEY_CHECK_HASH_TYPE_MD5) { return check_host_key_hash(s, hkc->u.hash.hash, - SSH_PUBLICKEY_HASH_MD5, errp); + SSH_PUBLICKEY_HASH_MD5, "md5", + errp); } else if (hkc->u.hash.type =3D=3D SSH_HOST_KEY_CHECK_HASH_TYPE_SH= A1) { return check_host_key_hash(s, hkc->u.hash.hash, - SSH_PUBLICKEY_HASH_SHA1, errp); + SSH_PUBLICKEY_HASH_SHA1, "sha1", + errp); } else if (hkc->u.hash.type =3D=3D SSH_HOST_KEY_CHECK_HASH_TYPE_SH= A256) { return check_host_key_hash(s, hkc->u.hash.hash, - SSH_PUBLICKEY_HASH_SHA256, errp); + SSH_PUBLICKEY_HASH_SHA256, "sha256", + errp); } g_assert_not_reached(); break; --=20 2.34.1