From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id zxYpHog+GVs4SgAAmS7hNA ; Thu, 07 Jun 2018 14:18:10 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id D7EE3608BF; Thu, 7 Jun 2018 14:18:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id 0CE4C602FC; Thu, 7 Jun 2018 14:18:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 0CE4C602FC Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933394AbeFGORy (ORCPT + 25 others); Thu, 7 Jun 2018 10:17:54 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:39550 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933097AbeFGOJN (ORCPT ); Thu, 7 Jun 2018 10:09:13 -0400 Received: from [148.252.241.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1fQvbD-0005a0-9C; Thu, 07 Jun 2018 15:09:11 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1fQvbA-00039M-7Z; Thu, 07 Jun 2018 15:09:08 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jarkko Sakkinen" , "Jeremy Boone" , "James Bottomley" , "James Morris" Date: Thu, 07 Jun 2018 15:05:21 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 296/410] tpm_i2c_nuvoton: fix potential buffer overruns caused by bit glitches on the bus In-Reply-To: X-SA-Exim-Connect-IP: 148.252.241.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.57-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jeremy Boone commit f9d4d9b5a5ef2f017bc344fb65a58a902517173b upstream. Discrete TPMs are often connected over slow serial buses which, on some platforms, can have glitches causing bit flips. In all the driver _recv() functions, we need to use a u32 to unmarshal the response size, otherwise a bit flip of the 31st bit would cause the expected variable to go negative, which would then try to read a huge amount of data. Also sanity check that the expected amount of data is large enough for the TPM header. Signed-off-by: Jeremy Boone Signed-off-by: James Bottomley Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: James Morris Signed-off-by: Ben Hutchings --- drivers/char/tpm/tpm_i2c_nuvoton.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/char/tpm/tpm_i2c_nuvoton.c +++ b/drivers/char/tpm/tpm_i2c_nuvoton.c @@ -267,7 +267,11 @@ static int i2c_nuvoton_recv(struct tpm_c struct device *dev = chip->dev; struct i2c_client *client = to_i2c_client(dev); s32 rc; - int expected, status, burst_count, retries, size = 0; + int status; + int burst_count; + int retries; + int size = 0; + u32 expected; if (count < TPM_HEADER_SIZE) { i2c_nuvoton_ready(chip); /* return to idle */ @@ -309,7 +313,7 @@ static int i2c_nuvoton_recv(struct tpm_c * to machine native */ expected = be32_to_cpu(*(__be32 *) (buf + 2)); - if (expected > count) { + if (expected > count || expected < size) { dev_err(dev, "%s() expected > count\n", __func__); size = -EIO; continue;