From patchwork Fri Jun 28 06:29:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baokun Li X-Patchwork-Id: 13715520 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 442236F2E6; Fri, 28 Jun 2024 06:31:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719556269; cv=none; b=DmF7oHjf1zXZiX/nNK36kdlFH+4mK5c5ITMfL7GVi0V40rq9O+vbSt93absEndEwDcD5z3peiD6UyLOJy3ngv08ZPIXAGDr2RTIjhvBbLXWeGfjzCOl3MVpZnnhvRFe2Z3xom/cjOAszK+eKvc1pZV/qxSK/YNZLUFqUG0+7dHQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719556269; c=relaxed/simple; bh=nft+9d/YjFcA3nqWZSNMApWV16/FmIhqW5jCfnBGGM0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=cYTeEomf363mlwbq9rqy8zpy2iE9ni7GZ+2WjpQHQYPjTx9AC5LXGQstWLkJcQmf5DU4GQFjgcMQuEQij8iFBolp7ahkeeigB8waDdwsIaj/caMJJg83l/HuHj/wMD6nTB2rX04NnlZP7Q1/780OaVRDDpwEzMfkX/W7c2bRQEU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4W9QYS0fpnz4f3kw4; Fri, 28 Jun 2024 14:30:52 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.75]) by mail.maildlp.com (Postfix) with ESMTP id 54B241A0572; Fri, 28 Jun 2024 14:31:04 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP2 (Coremail) with SMTP id Syh0CgBXwIWfWH5mZZVAAg--.52859S11; Fri, 28 Jun 2024 14:31:04 +0800 (CST) From: libaokun@huaweicloud.com To: netfs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org Cc: hsiangkao@linux.alibaba.com, jefflexu@linux.alibaba.com, zhujia.zj@bytedance.com, linux-erofs@lists.ozlabs.org, brauner@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libaokun@huaweicloud.com, yangerkun@huawei.com, houtao1@huawei.com, yukuai3@huawei.com, wozizhi@huawei.com, Baokun Li Subject: [PATCH v3 7/9] cachefiles: wait for ondemand_object_worker to finish when dropping object Date: Fri, 28 Jun 2024 14:29:28 +0800 Message-Id: <20240628062930.2467993-8-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240628062930.2467993-1-libaokun@huaweicloud.com> References: <20240628062930.2467993-1-libaokun@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: Syh0CgBXwIWfWH5mZZVAAg--.52859S11 X-Coremail-Antispam: 1UD129KBjvJXoW7Ww4kur4fJF1DXFy7Zw1UKFg_yoW8uF4fpF WakFy7KrWxWF4UCrWkZFs5XryrK3ykZFnrWFyYqrZ8Ar90qr4rZr12y3ZxZF15Aw1IgrZr tw4UCr9xt34qy3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUm014x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr1j6r xdM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0D M2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjx v20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1l F7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxan2 IY04v7M4kE6xkIj40Ew7xC0wCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8 JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1V AFwI0_GFv_WrylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xII jxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcV C2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVj vjDU0xZFpf9x0JUB89_UUUUU= X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/1tbiAQAIBV1jkH-xJwAAsL From: Hou Tao When queuing ondemand_object_worker() to re-open the object, cachefiles_object is not pinned. The cachefiles_object may be freed when the pending read request is completed intentionally and the related erofs is umounted. If ondemand_object_worker() runs after the object is freed, it will incur use-after-free problem as shown below. process A processs B process C process D cachefiles_ondemand_send_req() // send a read req X // wait for its completion // close ondemand fd cachefiles_ondemand_fd_release() // set object as CLOSE cachefiles_ondemand_daemon_read() // set object as REOPENING queue_work(fscache_wq, &info->ondemand_work) // close /dev/cachefiles cachefiles_daemon_release cachefiles_flush_reqs complete(&req->done) // read req X is completed // umount the erofs fs cachefiles_put_object() // object will be freed cachefiles_ondemand_deinit_obj_info() kmem_cache_free(object) // both info and object are freed ondemand_object_worker() When dropping an object, it is no longer necessary to reopen the object, so use cancel_work_sync() to cancel or wait for ondemand_object_worker() to finish. Fixes: 0a7e54c1959c ("cachefiles: resend an open request if the read request's object is closed") Signed-off-by: Hou Tao Signed-off-by: Baokun Li Reviewed-by: Jia Zhu Acked-by: Jeff Layton Reviewed-by: Gao Xiang --- fs/cachefiles/ondemand.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 36b97ded16b4..1d5b970206d0 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -694,6 +694,9 @@ void cachefiles_ondemand_clean_object(struct cachefiles_object *object) } } xa_unlock(&cache->reqs); + + /* Wait for ondemand_object_worker() to finish to avoid UAF. */ + cancel_work_sync(&object->ondemand->ondemand_work); } int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object,