From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC78AC43381 for ; Mon, 25 Mar 2019 22:10:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74E2E20857 for ; Mon, 25 Mar 2019 22:10:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FrawaBB6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731128AbfCYWKv (ORCPT ); Mon, 25 Mar 2019 18:10:51 -0400 Received: from mail-qk1-f201.google.com ([209.85.222.201]:40046 "EHLO mail-qk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731095AbfCYWKq (ORCPT ); Mon, 25 Mar 2019 18:10:46 -0400 Received: by mail-qk1-f201.google.com with SMTP id l187so9929603qkd.7 for ; Mon, 25 Mar 2019 15:10:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=d2w/jghx/Rqm9mT1Z9xpzhe5/Zw0d2YU0UIlwgQoEuk=; b=FrawaBB6eN8b4P/bVnjNhs6scGHBTE+TRJi3FQc+Wwj3NMeo6WCD3+HQbjxbbv7+WI wDvx0vr8l5x8DzoI7Tj5mPDrvDE+B/5x/IkMJfAz/BDDG/Xw1MnUdDSmAETbxxPgdsmX VYNfR2jows0dyDzxsN0D5o4jEVaObey0r1uqPlTIw9+c9pUY9s2qld90O2y0Nsj7j2dn T+Bpo74qJ+oGzlbqnocrS8st4xl4QLtcoBL8M5dUotNMJLJ1Fia6RrOf17DILTsA8kZN M6JQjp5NfHLIqjiyEugQs0B+MPF4ooHCAmn4/M9kSptz6VxUATW91wp/wM7IeI0PAiiR 5qig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=d2w/jghx/Rqm9mT1Z9xpzhe5/Zw0d2YU0UIlwgQoEuk=; b=ZnMgWgSECFxjTX67Lo3gw75UNx/pWpnQyKTZI6ZIUK9nPeMMVUyHot7ug5HirLeFkN dV4htZ+gt6nZKQFNWElO8dYGkzQYLmd3UKrg1Vh+neR9pfhB0GEcfCpfXMsK923MVlcv TuhgjF+8h/Y662Mre5gjQoaGv89pX8h3WXR5AIb+zd1K5WSzeckC8KZs+SsV2ASoDtZL HtH+4c86tZ9M+29AlANavUZD1+C8Cm5vE89TuAs92Bd4bd6g8VnocBJ3pwISl8MEtY0J zcE95FtuFsbKII8eF1vi77noFdpIwPxitA+QIDAKeb9ciFhAobldAzMLM7cucKhdUxbi G+PQ== X-Gm-Message-State: APjAAAVYMx/nEuhgvpA0nPpURhEVC7cj5ECRI4vK/ZLe3ftWn5DV4sP9 Pd/q5w2H1ilnuo5vnLNfCtSy1vX9q3CnejL0A/WISQ== X-Google-Smtp-Source: APXvYqzVTVmfctzgnwCAHNdEt4TH8ZQrL1tFaVyjQTLK8D82gLE4ptXXx53VXcErlNp281g0KEM8LQ1kT4/LgoRtBMESyw== X-Received: by 2002:a0c:e58f:: with SMTP id t15mr22962206qvm.170.1553551845625; Mon, 25 Mar 2019 15:10:45 -0700 (PDT) Date: Mon, 25 Mar 2019 15:09:45 -0700 In-Reply-To: <20190325220954.29054-1-matthewgarrett@google.com> Message-Id: <20190325220954.29054-19-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190325220954.29054-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH 18/27] Lock down TIOCSSERIAL From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, Matthew Garrett Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Howells Lock down TIOCSSERIAL as that can be used to change the ioport and irq settings on a serial port. This only appears to be an issue for the serial drivers that use the core serial code. All other drivers seem to either ignore attempts to change port/irq or give an error. Reported-by: Greg Kroah-Hartman Signed-off-by: David Howells cc: Jiri Slaby Cc: linux-serial@vger.kernel.org Signed-off-by: Matthew Garrett --- drivers/tty/serial/serial_core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index d4cca5bdaf1c..04534877b575 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -842,6 +842,12 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, new_flags = (__force upf_t)new_info->flags; old_custom_divisor = uport->custom_divisor; + if ((change_port || change_irq) && + kernel_is_locked_down("Using TIOCSSERIAL to change device addresses, irqs and dma channels")) { + retval = -EPERM; + goto exit; + } + if (!capable(CAP_SYS_ADMIN)) { retval = -EPERM; if (change_irq || change_port || -- 2.21.0.392.gf8f6787159e-goog