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[209.132.180.67]) by mx.google.com with ESMTP id l65si15081432plb.338.2019.04.03.17.35.48; Wed, 03 Apr 2019 17:36:03 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=MN1yXbqB; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728159AbfDDAdp (ORCPT + 99 others); Wed, 3 Apr 2019 20:33:45 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:54113 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727370AbfDDAdk (ORCPT ); Wed, 3 Apr 2019 20:33:40 -0400 Received: by mail-pf1-f202.google.com with SMTP id j18so504249pfi.20 for ; Wed, 03 Apr 2019 17:33:40 -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=h9EnFy04jMHVM1ZMNH2nx3A+bDTELFHTwxmLElxP71o=; b=MN1yXbqBCCTTy42BJKCEKzcNSpCVI9QaCSde6dHY9nVoglt6DHZ2fuci9W/00kyRF5 Ts6mPovN9ohlqPZjT2uk9sa9MxeuKSqBWm5zkVtm9dlesak92Ga9hE9Hja+66abKI+Es wB6u5AfgV5rWUrezpynHB8Nbg4bZ/03nLRF0kxyZevHMN1CjetAQK7ShhT+5aT+xSXO5 e9hH7f9vpdqsDa6dOJLdy1lO1U7EJpTlLKKf/3EJJ4UfxmHeiNt01Bd737BoJvtC/ZgY viDIrtHsf/jwB23jwY+pW4Vre06W3qyOVxhRl+DH6qY9vEIre409m6nmcFcDv4UR/Cl6 9AMA== 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=h9EnFy04jMHVM1ZMNH2nx3A+bDTELFHTwxmLElxP71o=; b=Qyn77mF1ME0VRa26G1zqcDA7bXBbfiiVAuIsC7/JCUnnNzLB7rCOgoXFLqY1agBmpe i9qFTAEGDLJEsxcfOTggMXZ34T++TEUNueuIAyPDK7+fVn0HUV+ikqauija5p9UqjPP1 Yu++P+FkzrUZwVqWT2OIYz2mz2+dKDSJWUWwoa1roKyymcWlT1lGuKVHnghNOKMSZ18P timtcFoAbbb8sIlBSagNtBfC+TSbE/qGbcYkpOubKDKMjn2wBVnaAzXt+ZTIZ7Oa2yF6 3LBIZQAYdY2A1EbAvHtX8qhkrbx2GsVfDu4nOESyIgH4v3aI0LMrQ4yez618Z1JboVx8 ndcw== X-Gm-Message-State: APjAAAUT4Kdlv+pKnSbGKpzJbJii5X2bZEM2N1tmzPCnDhBshFXR6Zgu zHWV7wUOiI6vx0E3rcW47nISnCTz/oQQL6Rn2G4r1A== X-Received: by 2002:a62:25c6:: with SMTP id l189mr75197pfl.19.1554338019633; Wed, 03 Apr 2019 17:33:39 -0700 (PDT) Date: Wed, 3 Apr 2019 17:32:39 -0700 In-Reply-To: <20190404003249.14356-1-matthewgarrett@google.com> Message-Id: <20190404003249.14356-18-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190404003249.14356-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH V32 17/27] 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, linux-api@vger.kernel.org, luto@kernel.org, Greg Kroah-Hartman , Matthew Garrett , Jiri Slaby , linux-serial@vger.kernel.org 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 Signed-off-by: Matthew Garrett cc: Jiri Slaby Cc: linux-serial@vger.kernel.org --- 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..65b67f0d4386 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", LOCKDOWN_INTEGRITY)) { + retval = -EPERM; + goto exit; + } + if (!capable(CAP_SYS_ADMIN)) { retval = -EPERM; if (change_irq || change_port || -- 2.21.0.392.gf8f6787159e-goog