From patchwork Thu May 16 07:56:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yue Haibing X-Patchwork-Id: 10945837 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8B726112C for ; Thu, 16 May 2019 07:57:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 73ACE28A7D for ; Thu, 16 May 2019 07:57:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5755828A91; Thu, 16 May 2019 07:57:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0799028A7D for ; Thu, 16 May 2019 07:57:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726374AbfEPH5V (ORCPT ); Thu, 16 May 2019 03:57:21 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:7655 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726363AbfEPH5V (ORCPT ); Thu, 16 May 2019 03:57:21 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 191AD6544DF4DFBF316D; Thu, 16 May 2019 15:57:19 +0800 (CST) Received: from localhost (10.177.31.96) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.439.0; Thu, 16 May 2019 15:57:12 +0800 From: YueHaibing To: , CC: , , , , YueHaibing Subject: [PATCH] spi: bitbang: Fix NULL pointer dereference in spi_unregister_master Date: Thu, 16 May 2019 15:56:56 +0800 Message-ID: <20190516075656.25880-1-yuehaibing@huawei.com> X-Mailer: git-send-email 2.10.2.windows.1 MIME-Version: 1.0 X-Originating-IP: [10.177.31.96] X-CFilter-Loop: Reflected Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If spi_register_master fails in spi_bitbang_start because device_add failure, We should return the error code other than 0, otherwise calling spi_bitbang_stop may trigger NULL pointer dereference like this: BUG: KASAN: null-ptr-deref in __list_del_entry_valid+0x45/0xd0 Read of size 8 at addr 0000000000000000 by task syz-executor.0/3661 CPU: 0 PID: 3661 Comm: syz-executor.0 Not tainted 5.1.0+ #28 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0xa9/0x10e ? __list_del_entry_valid+0x45/0xd0 ? __list_del_entry_valid+0x45/0xd0 __kasan_report+0x171/0x18d ? __list_del_entry_valid+0x45/0xd0 kasan_report+0xe/0x20 __list_del_entry_valid+0x45/0xd0 spi_unregister_controller+0x99/0x1b0 spi_lm70llp_attach+0x3ae/0x4b0 [spi_lm70llp] ? 0xffffffffc1128000 ? klist_next+0x131/0x1e0 ? driver_detach+0x40/0x40 [parport] port_check+0x3b/0x50 [parport] bus_for_each_dev+0x115/0x180 ? subsys_dev_iter_exit+0x20/0x20 __parport_register_driver+0x1f0/0x210 [parport] ? 0xffffffffc1150000 do_one_initcall+0xb9/0x3b5 ? perf_trace_initcall_level+0x270/0x270 ? kasan_unpoison_shadow+0x30/0x40 ? kasan_unpoison_shadow+0x30/0x40 do_init_module+0xe0/0x330 load_module+0x38eb/0x4270 ? module_frob_arch_sections+0x20/0x20 ? kernel_read_file+0x188/0x3f0 ? find_held_lock+0x6d/0xd0 ? fput_many+0x1a/0xe0 ? __do_sys_finit_module+0x162/0x190 __do_sys_finit_module+0x162/0x190 ? __ia32_sys_init_module+0x40/0x40 ? __mutex_unlock_slowpath+0xb4/0x3f0 ? wait_for_completion+0x240/0x240 ? vfs_write+0x160/0x2a0 ? lockdep_hardirqs_off+0xb5/0x100 ? mark_held_locks+0x1a/0x90 ? do_syscall_64+0x14/0x2a0 do_syscall_64+0x72/0x2a0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Reported-by: Hulk Robot Fixes: 702a4879ec33 ("spi: bitbang: Let spi_bitbang_start() take a reference to master") Signed-off-by: YueHaibing Reviewed-by: Geert Uytterhoeven Reviewed-by: Axel Lin Reviewed-by: Mukesh Ojha --- drivers/spi/spi-bitbang.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c index dd9a8c54..be95be4 100644 --- a/drivers/spi/spi-bitbang.c +++ b/drivers/spi/spi-bitbang.c @@ -403,7 +403,7 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) if (ret) spi_master_put(master); - return 0; + return ret; } EXPORT_SYMBOL_GPL(spi_bitbang_start);