From patchwork Mon Mar 13 22:27:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Khazhy Kumykov X-Patchwork-Id: 13173395 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A48D8C6FD1C for ; Mon, 13 Mar 2023 22:30:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229845AbjCMW37 (ORCPT ); Mon, 13 Mar 2023 18:29:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46414 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229742AbjCMW35 (ORCPT ); Mon, 13 Mar 2023 18:29:57 -0400 Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E19E6A2D1 for ; Mon, 13 Mar 2023 15:29:54 -0700 (PDT) Received: by mail-pl1-x62b.google.com with SMTP id v21so4488248ple.9 for ; Mon, 13 Mar 2023 15:29:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1678746594; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=0vVn1LLW9jGH3vizR2Vh0QqNw1Uoj7/4oaLgWURAUoE=; b=FDliuMCwyve+rDQBz3ikpE9QZV9Wgy+AmmYSmVsN4I6pOYIVhw2dOXfgLvo8WSjmGt 9pnm5xlpf3/+5fF1sEoLBpjRlCwoevAU0Py0Q3Fv3R4AEee8ctH5LXLpbkStvJSpF5xy DqQjjaJ0tq/iAj6Azmy4WScEwy8Jqc5j3bEc4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678746594; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=0vVn1LLW9jGH3vizR2Vh0QqNw1Uoj7/4oaLgWURAUoE=; b=E9TDuwXI49QYdyv9IQAsxeP7YKIDd3o3/cNIaa2/32QxaxMhsi+ecGUHKo85At0oN8 7haJfCXLfvc1kZUm9S+l5R/eqsrhKYytmVKIgkRZE4CvvDE4TmkExt6tJZuiPgzCew5i 1vJpGwaHhBWobyxdv0CbANwmjWMhJ0dgVSSTBkEhmEChYrRcQSPPZzBS3f2eewc2IIP9 /gELSzNf4Tjw7oAnJYxMPPtu74QRh6VqyN4uWpfMUPPTYlqxO2S9vVE6nb/anIPpyvrI RL4Ou1sajKwb422LyUlChuhZlncG1Y/8rpODr20pw+YiS9jMALye8f52c2G4hYPHG1l5 FlGg== X-Gm-Message-State: AO0yUKVFL5lgOCwLsipJdyeFxogjDt/BUg0aROTRfkO8THE6CrQf+VkW xGgckoz2jXJnGrpuVabx0qUnt70dpzMhwoYOKPM= X-Google-Smtp-Source: AK7set8JxLnbKfrXgkJSXgb3F/hTJt/RLi+cknWDSWt0Dzy0C8up3d5635IExrlxC3q2K75iExEWkw== X-Received: by 2002:a17:90b:1b4a:b0:237:b5d4:c0df with SMTP id nv10-20020a17090b1b4a00b00237b5d4c0dfmr35428420pjb.6.1678746593809; Mon, 13 Mar 2023 15:29:53 -0700 (PDT) Received: from khazhy-linux.svl.corp.google.com ([2620:15c:2d4:203:157:b07d:930a:fb24]) by smtp.gmail.com with ESMTPSA id km8-20020a17090327c800b0019aa8149cb9sm352440plb.79.2023.03.13.15.29.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Mar 2023 15:29:53 -0700 (PDT) From: Khazhismel Kumykov X-Google-Original-From: Khazhismel Kumykov To: stable@vger.kernel.org Cc: linux-block@vger.kernel.org, Yu Kuai , Jan Kara , Jens Axboe , Sasha Levin , Khazhismel Kumykov Subject: [PATCH v5.10 1/5] block, bfq: fix possible uaf for 'bfqq->bic' Date: Mon, 13 Mar 2023 15:27:53 -0700 Message-Id: <20230313222757.1103179-2-khazhy@google.com> X-Mailer: git-send-email 2.40.0.rc1.284.g88254d51c5-goog In-Reply-To: <20230313222757.1103179-1-khazhy@google.com> References: <20230313222757.1103179-1-khazhy@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Yu Kuai [ Upstream commit 64dc8c732f5c2b406cc752e6aaa1bd5471159cab ] Our test report a uaf for 'bfqq->bic' in 5.10: ================================================================== BUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30 CPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014 Call Trace: bfq_select_queue+0x378/0xa30 bfq_dispatch_request+0xe8/0x130 blk_mq_do_dispatch_sched+0x62/0xb0 __blk_mq_sched_dispatch_requests+0x215/0x2a0 blk_mq_sched_dispatch_requests+0x8f/0xd0 __blk_mq_run_hw_queue+0x98/0x180 __blk_mq_delay_run_hw_queue+0x22b/0x240 blk_mq_run_hw_queue+0xe3/0x190 blk_mq_sched_insert_requests+0x107/0x200 blk_mq_flush_plug_list+0x26e/0x3c0 blk_finish_plug+0x63/0x90 __iomap_dio_rw+0x7b5/0x910 iomap_dio_rw+0x36/0x80 ext4_dio_read_iter+0x146/0x190 [ext4] ext4_file_read_iter+0x1e2/0x230 [ext4] new_sync_read+0x29f/0x400 vfs_read+0x24e/0x2d0 ksys_read+0xd5/0x1b0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x61/0xc6 Commit 3bc5e683c67d ("bfq: Split shared queues on move between cgroups") changes that move process to a new cgroup will allocate a new bfqq to use, however, the old bfqq and new bfqq can point to the same bic: 1) Initial state, two process with io in the same cgroup. Process 1 Process 2 (BIC1) (BIC2) | Λ | Λ | | | | V | V | bfqq1 bfqq2 2) bfqq1 is merged to bfqq2. Process 1 Process 2 (BIC1) (BIC2) | | \-------------\| V bfqq1 bfqq2(coop) 3) Process 1 exit, then issue new io(denoce IOA) from Process 2. (BIC2) | Λ | | V | bfqq2(coop) 4) Before IOA is completed, move Process 2 to another cgroup and issue io. Process 2 (BIC2) Λ |\--------------\ | V bfqq2 bfqq3 Now that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2. If all the requests are completed, and Process 2 exit, BIC2 will be freed while there is no guarantee that bfqq2 will be freed before BIC2. Fix the problem by clearing bfqq->bic while bfqq is detached from bic. Fixes: 3bc5e683c67d ("bfq: Split shared queues on move between cgroups") Suggested-by: Jan Kara Signed-off-by: Yu Kuai Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20221214030430.3304151-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Khazhismel Kumykov --- block/bfq-iosched.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 7c4b8d0635eb..afaededb3c49 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -373,6 +373,12 @@ struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync) void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync) { + struct bfq_queue *old_bfqq = bic->bfqq[is_sync]; + + /* Clear bic pointer if bfqq is detached from this bic */ + if (old_bfqq && old_bfqq->bic == bic) + old_bfqq->bic = NULL; + bic->bfqq[is_sync] = bfqq; } @@ -4977,7 +4983,6 @@ static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync) unsigned long flags; spin_lock_irqsave(&bfqd->lock, flags); - bfqq->bic = NULL; bfq_exit_bfqq(bfqd, bfqq); bic_set_bfqq(bic, NULL, is_sync); spin_unlock_irqrestore(&bfqd->lock, flags);