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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 B80A1C433DF for ; Mon, 17 Aug 2020 17:09:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96D372067C for ; Mon, 17 Aug 2020 17:09:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597684182; bh=b6eX7ifBXiMIhLGrhTJBbIm8XMK4WsR85T2xCvWD8Cw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ItlOLCGtNdo3I438n6DfQIJtuUbnaS8Et6hsdnOd/jkKbaP44dmsDRw3marIgXFjR N95lAdb10tT5ls8ZMHOswHdXNLWV9lEkwPpKf9vTOrO02BDsmUPYc4u7XhrytU6PXe FCGjzw8N3Fm9xPQGaXClNU4txZ+f+sjLlUqQt20o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389373AbgHQRJ2 (ORCPT ); Mon, 17 Aug 2020 13:09:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:35950 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388413AbgHQQKp (ORCPT ); Mon, 17 Aug 2020 12:10:45 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 5204322BED; Mon, 17 Aug 2020 16:10:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597680644; bh=b6eX7ifBXiMIhLGrhTJBbIm8XMK4WsR85T2xCvWD8Cw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PMHDbrmQnqIEV1kU9iDfoCWLIVCgDluQVTxiJ0g/rYwTlpUHn8V7of7N3SA9+8sAY vomn9cNvxcfcM+1wmMNlNa/Fp6NH4GdlSaPR8/anYFaXb3HzPNY6is8kAmtKiZy0LZ x8CC03V2q/jF+NgRAJYjiNXu2TE0FLjCbp0FTjaM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guoyu Huang , Jens Axboe Subject: [PATCH 5.4 270/270] io_uring: Fix NULL pointer dereference in loop_rw_iter() Date: Mon, 17 Aug 2020 17:17:51 +0200 Message-Id: <20200817143809.254945655@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143755.807583758@linuxfoundation.org> References: <20200817143755.807583758@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 From: Guoyu Huang commit 2dd2111d0d383df104b144e0d1f6b5a00cb7cd88 upstream. loop_rw_iter() does not check whether the file has a read or write function. This can lead to NULL pointer dereference when the user passes in a file descriptor that does not have read or write function. The crash log looks like this: [ 99.834071] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 99.835364] #PF: supervisor instruction fetch in kernel mode [ 99.836522] #PF: error_code(0x0010) - not-present page [ 99.837771] PGD 8000000079d62067 P4D 8000000079d62067 PUD 79d8c067 PMD 0 [ 99.839649] Oops: 0010 [#2] SMP PTI [ 99.840591] CPU: 1 PID: 333 Comm: io_wqe_worker-0 Tainted: G D 5.8.0 #2 [ 99.842622] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 [ 99.845140] RIP: 0010:0x0 [ 99.845840] Code: Bad RIP value. [ 99.846672] RSP: 0018:ffffa1c7c01ebc08 EFLAGS: 00010202 [ 99.848018] RAX: 0000000000000000 RBX: ffff92363bd67300 RCX: ffff92363d461208 [ 99.849854] RDX: 0000000000000010 RSI: 00007ffdbf696bb0 RDI: ffff92363bd67300 [ 99.851743] RBP: ffffa1c7c01ebc40 R08: 0000000000000000 R09: 0000000000000000 [ 99.853394] R10: ffffffff9ec692a0 R11: 0000000000000000 R12: 0000000000000010 [ 99.855148] R13: 0000000000000000 R14: ffff92363d461208 R15: ffffa1c7c01ebc68 [ 99.856914] FS: 0000000000000000(0000) GS:ffff92363dd00000(0000) knlGS:0000000000000000 [ 99.858651] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 99.860032] CR2: ffffffffffffffd6 CR3: 000000007ac66000 CR4: 00000000000006e0 [ 99.861979] Call Trace: [ 99.862617] loop_rw_iter.part.0+0xad/0x110 [ 99.863838] io_write+0x2ae/0x380 [ 99.864644] ? kvm_sched_clock_read+0x11/0x20 [ 99.865595] ? sched_clock+0x9/0x10 [ 99.866453] ? sched_clock_cpu+0x11/0xb0 [ 99.867326] ? newidle_balance+0x1d4/0x3c0 [ 99.868283] io_issue_sqe+0xd8f/0x1340 [ 99.869216] ? __switch_to+0x7f/0x450 [ 99.870280] ? __switch_to_asm+0x42/0x70 [ 99.871254] ? __switch_to_asm+0x36/0x70 [ 99.872133] ? lock_timer_base+0x72/0xa0 [ 99.873155] ? switch_mm_irqs_off+0x1bf/0x420 [ 99.874152] io_wq_submit_work+0x64/0x180 [ 99.875192] ? kthread_use_mm+0x71/0x100 [ 99.876132] io_worker_handle_work+0x267/0x440 [ 99.877233] io_wqe_worker+0x297/0x350 [ 99.878145] kthread+0x112/0x150 [ 99.878849] ? __io_worker_unuse+0x100/0x100 [ 99.879935] ? kthread_park+0x90/0x90 [ 99.880874] ret_from_fork+0x22/0x30 [ 99.881679] Modules linked in: [ 99.882493] CR2: 0000000000000000 [ 99.883324] ---[ end trace 4453745f4673190b ]--- [ 99.884289] RIP: 0010:0x0 [ 99.884837] Code: Bad RIP value. [ 99.885492] RSP: 0018:ffffa1c7c01ebc08 EFLAGS: 00010202 [ 99.886851] RAX: 0000000000000000 RBX: ffff92363acd7f00 RCX: ffff92363d461608 [ 99.888561] RDX: 0000000000000010 RSI: 00007ffe040d9e10 RDI: ffff92363acd7f00 [ 99.890203] RBP: ffffa1c7c01ebc40 R08: 0000000000000000 R09: 0000000000000000 [ 99.891907] R10: ffffffff9ec692a0 R11: 0000000000000000 R12: 0000000000000010 [ 99.894106] R13: 0000000000000000 R14: ffff92363d461608 R15: ffffa1c7c01ebc68 [ 99.896079] FS: 0000000000000000(0000) GS:ffff92363dd00000(0000) knlGS:0000000000000000 [ 99.898017] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 99.899197] CR2: ffffffffffffffd6 CR3: 000000007ac66000 CR4: 00000000000006e0 Fixes: 32960613b7c3 ("io_uring: correctly handle non ->{read,write}_iter() file_operations") Cc: stable@vger.kernel.org Signed-off-by: Guoyu Huang Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1433,8 +1433,10 @@ static int io_read(struct io_kiocb *req, if (file->f_op->read_iter) ret2 = call_read_iter(file, kiocb, &iter); - else + else if (req->file->f_op->read) ret2 = loop_rw_iter(READ, file, kiocb, &iter); + else + ret2 = -EINVAL; /* * In case of a short read, punt to async. This can happen @@ -1524,8 +1526,10 @@ static int io_write(struct io_kiocb *req if (file->f_op->write_iter) ret2 = call_write_iter(file, kiocb, &iter); - else + else if (req->file->f_op->write) ret2 = loop_rw_iter(WRITE, file, kiocb, &iter); + else + ret2 = -EINVAL; if (!force_nonblock) current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;