From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63458883F for ; Mon, 7 Sep 2026 01:13:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788743615; cv=none; b=WW4CdgE1n0Bmvy1vv24KRJfMYdUw6GhWV5w0MdXiTjT7UwqjvTYHPfSCFI4Ot3Q6DFHx6GS/T7aTTijdd7X+nWKw4OsKChjSQGecf2uNvhlmF0n4iX+1tcGF62EQKQFg35gOvK5kKqw6ultl8yHb2H5qI44HvJC0hhn/q7KWvzE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788743615; c=relaxed/simple; bh=jaWlZQ8ZlepsXQeU/Fu3ZhfWxiqbDlA2okrOO0lKyEs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=BNml0znn5CA0YenR/wseuwUOky0eVpRckMfXdCzUybrtMg8e4Kie1Hayvfu/KVclhBAlKXP1tGn1hSvNmHq5+8Ucm0ZnNdl++YVkY28kVxWwPaHF8WPJpOVyra+xihcMUvY/k8PZusbp7eZjzmjhbSvLXRLz63lfaKbTUbphZ+w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ddzGR1Rv; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ddzGR1Rv" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788743612; 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; bh=QMWXx1ovvXjj2qdmg/hVr5qGuFy+Konf1Hz2tVgqduU=; b=ddzGR1RvkdH02lX80z0RSmOVzFCVnbze56CqPzkJ1mMwuXjTrCz2jPJKOF2NvM6V7pG0Sm HJdNlnACPcrtAOtkZxcf6qHrqq/KaFuur79ELLwKRZMHs3zy26EGgW08oBdHP+uv8ABIN1 BJ9In4/1o6gWC/9lHHW8IbCoATah53A= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-175-Lf1Fr1W2MJibI5aWQGjlBA-1; Sun, 06 Sep 2026 21:13:30 -0400 X-MC-Unique: Lf1Fr1W2MJibI5aWQGjlBA-1 X-Mimecast-MFC-AGG-ID: Lf1Fr1W2MJibI5aWQGjlBA_1788743610 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EBF271954219 for ; Mon, 7 Sep 2026 01:13:29 +0000 (UTC) Received: from okorniev-mac.redhat.com (unknown [10.22.64.31]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 5A0AA1800347; Mon, 7 Sep 2026 01:13:29 +0000 (UTC) From: Olga Kornievskaia To: steved@redhat.com Cc: linux-nfs@vger.kernel.org Subject: [PATCH 1/1] fsidd: require root credentials on abstract socket Date: Sun, 6 Sep 2026 21:13:25 -0400 Message-ID: <20260907011328.21425-1-okorniev@redhat.com> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 fsidd listens on an abstract UNIX domain socket which has no filesystem-level access control.  Any local unprivileged user can connect and issue mutating commands (get_or_create_fsidnum) that grow the reexport database without limit, degrading mountd performance. Add a SO_PEERCRED check to reject connections from non-root clients.  The only legitimate client is mountd, which runs as root. Fixes: 6fd2732d ("export: Add fsidd") Signed-off-by: Olga Kornievskaia --- support/reexport/fsidd.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/support/reexport/fsidd.c b/support/reexport/fsidd.c index 9b80b451..c714386e 100644 --- a/support/reexport/fsidd.c +++ b/support/reexport/fsidd.c @@ -7,6 +7,7 @@ #include #endif #include +#include #include #include @@ -147,6 +148,8 @@ static void srv_cb(evutil_socket_t fd, short ev, void *d) { int cl = accept4(fd, NULL, NULL, SOCK_NONBLOCK); struct event *client_ev; + struct ucred cred; + socklen_t clen = sizeof(cred); if (cl == -1) { if (errno == EMFILE || errno == ENFILE || errno == ENOMEM || @@ -162,6 +165,12 @@ static void srv_cb(evutil_socket_t fd, short ev, void *d) (void)ev; (void)d; + if (getsockopt(cl, SOL_SOCKET, SO_PEERCRED, &cred, &clen) < 0 || + cred.uid != 0) { + close(cl); + return; + } + client_ev = event_new(evbase, cl, EV_READ | EV_PERSIST | EV_CLOSED, client_cb, event_self_cbarg()); if (!client_ev || event_add(client_ev, NULL) == -1) { if (client_ev) -- 2.52.0