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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE7CDC433FE for ; Mon, 25 Oct 2021 19:18:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C1FA26109E for ; Mon, 25 Oct 2021 19:18:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234434AbhJYTVJ (ORCPT ); Mon, 25 Oct 2021 15:21:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:38296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234573AbhJYTUE (ORCPT ); Mon, 25 Oct 2021 15:20:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 30C9F6103C; Mon, 25 Oct 2021 19:17:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1635189461; bh=oFeud0A2uIlaNfeGkWC8QwUsaeEnJjXyeWUwVPbfCdI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xqWPoWaA5tb+a6fOMiIn3t/nNgRr329Fsedb66dS/bUKIKlKyBXz81BBbDm14ZEDV HIjVOHqTY+q7W182yvOMUIPLwZrBqIfNrIrsVq0mA0ExZnuXHiZqbgu88X5zvxYN2V 9Bj7usjC43pFYJo4fNOJdVvS3So5Q9BGfxp4mlqk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Douglas Anderson , Stephen Boyd , Srinivas Kandagatla Subject: [PATCH 4.9 10/50] nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells Date: Mon, 25 Oct 2021 21:13:57 +0200 Message-Id: <20211025190934.921745976@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211025190932.542632625@linuxfoundation.org> References: <20211025190932.542632625@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Stephen Boyd commit 5d388fa01fa6eb310ac023a363a6cb216d9d8fe9 upstream. If a cell has 'nbits' equal to a multiple of BITS_PER_BYTE the logic *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0); will become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we subtract one from that making a large number that is then shifted more than the number of bits that fit into an unsigned long. UBSAN reports this problem: UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8 shift exponent 64 is too large for 64-bit type 'unsigned long' CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9 Hardware name: Google Lazor (rev3+) with KB Backlight (DT) Workqueue: events_unbound deferred_probe_work_func Call trace: dump_backtrace+0x0/0x170 show_stack+0x24/0x30 dump_stack_lvl+0x64/0x7c dump_stack+0x18/0x38 ubsan_epilogue+0x10/0x54 __ubsan_handle_shift_out_of_bounds+0x180/0x194 __nvmem_cell_read+0x1ec/0x21c nvmem_cell_read+0x58/0x94 nvmem_cell_read_variable_common+0x4c/0xb0 nvmem_cell_read_variable_le_u32+0x40/0x100 a6xx_gpu_init+0x170/0x2f4 adreno_bind+0x174/0x284 component_bind_all+0xf0/0x264 msm_drm_bind+0x1d8/0x7a0 try_to_bring_up_master+0x164/0x1ac __component_add+0xbc/0x13c component_add+0x20/0x2c dp_display_probe+0x340/0x384 platform_probe+0xc0/0x100 really_probe+0x110/0x304 __driver_probe_device+0xb8/0x120 driver_probe_device+0x4c/0xfc __device_attach_driver+0xb0/0x128 bus_for_each_drv+0x90/0xdc __device_attach+0xc8/0x174 device_initial_probe+0x20/0x2c bus_probe_device+0x40/0xa4 deferred_probe_work_func+0x7c/0xb8 process_one_work+0x128/0x21c process_scheduled_works+0x40/0x54 worker_thread+0x1ec/0x2a8 kthread+0x138/0x158 ret_from_fork+0x10/0x20 Fix it by making sure there are any bits to mask out. Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers") Cc: Douglas Anderson Cc: stable@vger.kernel.org Signed-off-by: Stephen Boyd Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20211013124511.18726-1-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/nvmem/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -967,7 +967,8 @@ static inline void nvmem_shift_read_buff *p-- = 0; /* clear msb bits if any leftover in the last byte */ - *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0); + if (cell->nbits % BITS_PER_BYTE) + *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0); } static int __nvmem_cell_read(struct nvmem_device *nvmem,