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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 9B671C433E0 for ; Mon, 29 Jun 2020 18:35:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B8D5222C3 for ; Mon, 29 Jun 2020 18:35:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593455741; bh=YcBvkHLseg2B1KadSr98e/e+pOnVHrMnbfzANZoWk7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=quse4LGdXbkRnoUuWKOFVZgxEb3t8ZQm28CdtcwG2fD3JZIzFvO+oYf/G0tDUFZiN 5NsaEErtvo7ll7puoWjrK/UR6Oc5XFClhIrzddhD1AAjha40jJBN/0sADbysPlFhPu eMT4H/Tl6DPVi/IpYnpMqQrjPjyviyhE1v03WjLQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726047AbgF2Sfk (ORCPT ); Mon, 29 Jun 2020 14:35:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:56794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726186AbgF2SfW (ORCPT ); Mon, 29 Jun 2020 14:35:22 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CB00124749; Mon, 29 Jun 2020 15:21:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593444068; bh=YcBvkHLseg2B1KadSr98e/e+pOnVHrMnbfzANZoWk7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BOP7MwMqWc1zEQUxwvWPEHvhPxK7pCjIv0iBN2dD7GdwQu5YkB5tV1pR1crzsP8Gh P6SAGwQaJAue3ZGiOAav3o1164LJJN7qwYsT2vxE9Cq2yYD6EddzyjsWQB+uikLwft PsnAu0YqQbKeajNpefEyozJYn/4ZsFh1Jhm7/01U= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mans Rullgard , Wolfram Sang , Sasha Levin Subject: [PATCH 5.7 177/265] i2c: core: check returned size of emulated smbus block read Date: Mon, 29 Jun 2020 11:16:50 -0400 Message-Id: <20200629151818.2493727-178-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629151818.2493727-1-sashal@kernel.org> References: <20200629151818.2493727-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.7.7-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.7.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.7.7-rc1 X-KernelTest-Deadline: 2020-07-01T15:14+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mans Rullgard [ Upstream commit 40e05200593af06633f64ab0effff052eee6f076 ] If the i2c bus driver ignores the I2C_M_RECV_LEN flag (as some of them do), it is possible for an I2C_SMBUS_BLOCK_DATA read issued on some random device to return an arbitrary value in the first byte (and nothing else). When this happens, i2c_smbus_xfer_emulated() will happily write past the end of the supplied data buffer, thus causing Bad Things to happen. To prevent this, check the size before copying the data block and return an error if it is too large. Fixes: 209d27c3b167 ("i2c: Emulate SMBus block read over I2C") Signed-off-by: Mans Rullgard [wsa: use better errno] Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/i2c-core-smbus.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index b34d2ff069318..bbb70a8a411e3 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -495,6 +495,13 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, break; case I2C_SMBUS_BLOCK_DATA: case I2C_SMBUS_BLOCK_PROC_CALL: + if (msg[1].buf[0] > I2C_SMBUS_BLOCK_MAX) { + dev_err(&adapter->dev, + "Invalid block size returned: %d\n", + msg[1].buf[0]); + status = -EPROTO; + goto cleanup; + } for (i = 0; i < msg[1].buf[0] + 1; i++) data->block[i] = msg[1].buf[i]; break; -- 2.25.1