From patchwork Mon May 18 17:36:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 225794 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=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 9E1AFC433E1 for ; Mon, 18 May 2020 17:55:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77E9620878 for ; Mon, 18 May 2020 17:55:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589824537; bh=BEUWMUQxwatFeo/5l8VvlQUF3ITZ2kX7a3zK9Hqp7dw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xVK+Mi9h/H6toS2d0jDlHs1Bo3NAFlJqlHj8kUjffFWOBYkuuoI2VZvbc573Lq9JN 4qT7H3z8TOyoC/gtok13uY8mBFNqGOsCNw0DHp8s4GQT3BWysN8c/Xm9w7epc2E36l neYMr/0hfierB4MWnzzHWZC3s893q2fvRuOQntuE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731459AbgERRzd (ORCPT ); Mon, 18 May 2020 13:55:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:32818 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731454AbgERRzc (ORCPT ); Mon, 18 May 2020 13:55:32 -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 14FA3207C4; Mon, 18 May 2020 17:55:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589824532; bh=BEUWMUQxwatFeo/5l8VvlQUF3ITZ2kX7a3zK9Hqp7dw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N5tWIC67FPjwt1xw9fyhBcv4lGi5Etoza48WISMRGyZN8+KSVKig9k7eo5F9lssKh 3hdGv13IKYtnyMWEhKqqRBLDlMQuRrNBr6Q+dC/veOaw2Ow+GtAI/LLXWyF6nsZD5w FZWuN5v3r8gty2pO0kHihu/bHTPGPFhzO8drWow8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Schwab , Randy Dunlap , Vasily Averin , Andrew Morton , Waiman Long , NeilBrown , Steven Rostedt , Ingo Molnar , Peter Oberparleiter , Davidlohr Bueso , Manfred Spraul , Linus Torvalds , Sasha Levin Subject: [PATCH 5.4 050/147] ipc/util.c: sysvipc_find_ipc() incorrectly updates position index Date: Mon, 18 May 2020 19:36:13 +0200 Message-Id: <20200518173520.206794779@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173513.009514388@linuxfoundation.org> References: <20200518173513.009514388@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vasily Averin [ Upstream commit 5e698222c70257d13ae0816720dde57c56f81e15 ] Commit 89163f93c6f9 ("ipc/util.c: sysvipc_find_ipc() should increase position index") is causing this bug (seen on 5.6.8): # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages # ipcmk -Q Message queue id: 0 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x82db8127 0 root 644 0 0 # ipcmk -Q Message queue id: 1 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x82db8127 0 root 644 0 0 0x76d1fb2a 1 root 644 0 0 # ipcrm -q 0 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x76d1fb2a 1 root 644 0 0 0x76d1fb2a 1 root 644 0 0 # ipcmk -Q Message queue id: 2 # ipcrm -q 2 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x76d1fb2a 1 root 644 0 0 0x76d1fb2a 1 root 644 0 0 # ipcmk -Q Message queue id: 3 # ipcrm -q 1 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x7c982867 3 root 644 0 0 0x7c982867 3 root 644 0 0 0x7c982867 3 root 644 0 0 0x7c982867 3 root 644 0 0 Whenever an IPC item with a low id is deleted, the items with higher ids are duplicated, as if filling a hole. new_pos should jump through hole of unused ids, pos can be updated inside "for" cycle. Fixes: 89163f93c6f9 ("ipc/util.c: sysvipc_find_ipc() should increase position index") Reported-by: Andreas Schwab Reported-by: Randy Dunlap Signed-off-by: Vasily Averin Signed-off-by: Andrew Morton Acked-by: Waiman Long Cc: NeilBrown Cc: Steven Rostedt Cc: Ingo Molnar Cc: Peter Oberparleiter Cc: Davidlohr Bueso Cc: Manfred Spraul Cc: Link: http://lkml.kernel.org/r/4921fe9b-9385-a2b4-1dc4-1099be6d2e39@virtuozzo.com Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- ipc/util.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/ipc/util.c b/ipc/util.c index 594871610d454..1821b6386d3b4 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -764,21 +764,21 @@ static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, total++; } - *new_pos = pos + 1; + ipc = NULL; if (total >= ids->in_use) - return NULL; + goto out; for (; pos < ipc_mni; pos++) { ipc = idr_find(&ids->ipcs_idr, pos); if (ipc != NULL) { rcu_read_lock(); ipc_lock_object(ipc); - return ipc; + break; } } - - /* Out of range - return NULL to terminate iteration */ - return NULL; +out: + *new_pos = pos + 1; + return ipc; } static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)