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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 770C9C10F11 for ; Wed, 24 Apr 2019 18:01:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48C0020652 for ; Wed, 24 Apr 2019 18:01:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556128893; bh=8AlYgIs51mkc4FfgjctCB01dZGmYgCGa7ChWtTmJwOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ae8E08eITF3hLuMuEX6pZZshVD9yFXmLsW0yBdDrHUrnTbLm/SMs19Qmr/But+E/6 4ZFt5hd36SsGlMtdCQNiDT+vGzGdkskZY/Ge9BewFovEksczOKNWZElnOZW0vLVz4R iOyRxloS33cSGh8Z9taw3LcyEB0sUsLRHAo+KgEY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388868AbfDXRWA (ORCPT ); Wed, 24 Apr 2019 13:22:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:47436 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389067AbfDXRV6 (ORCPT ); Wed, 24 Apr 2019 13:21:58 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8C05921909; Wed, 24 Apr 2019 17:21:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126517; bh=8AlYgIs51mkc4FfgjctCB01dZGmYgCGa7ChWtTmJwOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MPbaZAASlV1TzvsIh2BIBpFwuTtM1UA6dAk45R22rthOtw99wM0legYjBQh74CYdJ FpMuMxL6DNVp+eCxgAQhe3Gc6REsLbXp6ole1uZm2YU2efN4lu0J+zZ9vxaHGIudE/ 3CCDlvJkX9coFZOfj/HLdg29flPVCZBKVoPt9qg4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Morris , Tomas Winkler , Jerry Snitselaar , Jarkko Sakkinen , "Sasha Levin (Microsoft)" Subject: [PATCH 4.4 134/168] tpm/tpm_crb: Avoid unaligned reads in crb_recv() Date: Wed, 24 Apr 2019 19:09:38 +0200 Message-Id: <20190424170931.217300605@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170923.452349382@linuxfoundation.org> References: <20190424170923.452349382@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit 3d7a850fdc1a2e4d2adbc95cc0fc962974725e88 upstream The current approach to read first 6 bytes from the response and then tail of the response, can cause the 2nd memcpy_fromio() to do an unaligned read (e.g. read 32-bit word from address aligned to a 16-bits), depending on how memcpy_fromio() is implemented. If this happens, the read will fail and the memory controller will fill the read with 1's. This was triggered by 170d13ca3a2f, which should be probably refined to check and react to the address alignment. Before that commit, on x86 memcpy_fromio() turned out to be memcpy(). By a luck GCC has done the right thing (from tpm_crb's perspective) for us so far, but we should not rely on that. Thus, it makes sense to fix this also in tpm_crb, not least because the fix can be then backported to stable kernels and make them more robust when compiled in differing environments. Cc: stable@vger.kernel.org Cc: James Morris Cc: Tomas Winkler Cc: Jerry Snitselaar Fixes: 30fc8d138e91 ("tpm: TPM 2.0 CRB Interface") Signed-off-by: Jarkko Sakkinen Reviewed-by: Jerry Snitselaar Acked-by: Tomas Winkler Signed-off-by: Sasha Levin (Microsoft) --- drivers/char/tpm/tpm_crb.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c index 35308dfff754..8226e3b6dc1f 100644 --- a/drivers/char/tpm/tpm_crb.c +++ b/drivers/char/tpm/tpm_crb.c @@ -109,19 +109,29 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count) struct crb_priv *priv = chip->vendor.priv; unsigned int expected; - /* sanity check */ - if (count < 6) + /* A sanity check that the upper layer wants to get at least the header + * as that is the minimum size for any TPM response. + */ + if (count < TPM_HEADER_SIZE) return -EIO; + /* If this bit is set, according to the spec, the TPM is in + * unrecoverable condition. + */ if (le32_to_cpu(ioread32(&priv->cca->sts)) & CRB_CA_STS_ERROR) return -EIO; - memcpy_fromio(buf, priv->rsp, 6); - expected = be32_to_cpup((__be32 *) &buf[2]); - if (expected > count || expected < 6) + /* Read the first 8 bytes in order to get the length of the response. + * We read exactly a quad word in order to make sure that the remaining + * reads will be aligned. + */ + memcpy_fromio(buf, priv->rsp, 8); + + expected = be32_to_cpup((__be32 *)&buf[2]); + if (expected > count || expected < TPM_HEADER_SIZE) return -EIO; - memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6); + memcpy_fromio(&buf[8], &priv->rsp[8], expected - 8); return expected; } -- 2.19.1