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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 7374BC433FE for ; Sat, 11 Sep 2021 13:12:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 57AB161206 for ; Sat, 11 Sep 2021 13:12:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235966AbhIKNNZ (ORCPT ); Sat, 11 Sep 2021 09:13:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:36714 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235829AbhIKNNJ (ORCPT ); Sat, 11 Sep 2021 09:13:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id F2EEB6108B; Sat, 11 Sep 2021 13:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631365916; bh=hG+7UnzuY21Kf9pUuVV2XycR5F+kwOT2KtokM/cSP+U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JCkQB2kKArW0oTJfGgDUus9vJRXeI752LvHmg/OOWcbtI1oc6rlH3WYL6oTM9/zvC 6zwX+JAqZiBp7hBUp+wh7Z1Xt4qq/3aos8aUKpUb6M2zQBUNXgeN62U3J9MdJkbVx6 Miq1AC1cKVJHvEIG/q7+KOoeykWnQITbx/UiwSvsZRGb/MBpbAZIvik9ChBbuqBvwh wLKkhV2i2Ru/WKK9yAGrHf+p/VylFyscNxZO5L2hP4ItR3LJ9lXnyl3kYYJ6BO+bSX 15U6sDRBmfDQ5f+x9GHEnbQHNHGdvnNaZXDtpkUYs+9Xyp5QK0LZ0SSin+catvTC89 ZzhaoAZW4EWrg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Miklos Szeredi , lijiazi , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 5.14 05/32] fuse: fix use after free in fuse_read_interrupt() Date: Sat, 11 Sep 2021 09:11:22 -0400 Message-Id: <20210911131149.284397-5-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210911131149.284397-1-sashal@kernel.org> References: <20210911131149.284397-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Miklos Szeredi [ Upstream commit e1e71c168813564be0f6ea3d6740a059ca42d177 ] There is a potential race between fuse_read_interrupt() and fuse_request_end(). TASK1 in fuse_read_interrupt(): delete req->intr_entry (while holding fiq->lock) TASK2 in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock wake up TASK3 TASK3 request is freed TASK1 in fuse_read_interrupt(): dereference req->in.h.unique ***BAM*** Fix by always grabbing fiq->lock if the request was ever interrupted (FR_INTERRUPTED set) thereby serializing with concurrent fuse_read_interrupt() calls. FR_INTERRUPTED is set before the request is queued on fiq->interrupts. Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not cleared in this case. Reported-by: lijiazi Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin --- fs/fuse/dev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 1c8f79b3dd06..dde341a6388a 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -288,10 +288,10 @@ void fuse_request_end(struct fuse_req *req) /* * test_and_set_bit() implies smp_mb() between bit - * changing and below intr_entry check. Pairs with + * changing and below FR_INTERRUPTED check. Pairs with * smp_mb() from queue_interrupt(). */ - if (!list_empty(&req->intr_entry)) { + if (test_bit(FR_INTERRUPTED, &req->flags)) { spin_lock(&fiq->lock); list_del_init(&req->intr_entry); spin_unlock(&fiq->lock); -- 2.30.2