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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41F65C433EF for ; Tue, 29 Mar 2022 18:34:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240591AbiC2Sft (ORCPT ); Tue, 29 Mar 2022 14:35:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240556AbiC2Sff (ORCPT ); Tue, 29 Mar 2022 14:35:35 -0400 Received: from mail-qk1-x729.google.com (mail-qk1-x729.google.com [IPv6:2607:f8b0:4864:20::729]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7285323140 for ; Tue, 29 Mar 2022 11:33:52 -0700 (PDT) Received: by mail-qk1-x729.google.com with SMTP id 1so14825016qke.1 for ; Tue, 29 Mar 2022 11:33:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vWA7HcHxRpWtEbVOYRkc14CrV3xH0f9ykow83uQI6Oc=; b=TGAfGZeUItf+EdBmKHvq/2lKgRAqtSOyPTJ3cIwzNwRXU6NEbCqLYag1qggqY920kV cLpNhwg8PEBGMVp+7YAlNt2AZec4QPKGCGxm8GAYJjlZOIjJyc4pdCjSIBiV68cQREzj RpezyPsr0Zc6OgGORxiIZ1uy2+dWR2GmnjtpwpY+t/eoSp+XqqRleYDRXMAfcj9/vndG IC6FAoCJgJ45lmGcaVEFqFp4WI6vIN4OpkuRVDrJdXY8/OutwXgLzrlHQoX+D05G/whr otQ0Q5eD/J/839YermdMlOdL6AyKoKD5EaKYUKknuWkrJMP0gJNvvc5rgqWaJ9yW3IqZ 41oQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=vWA7HcHxRpWtEbVOYRkc14CrV3xH0f9ykow83uQI6Oc=; b=O9Z3TOFOO+POSpGpBI0Qef6L/nVJst72JxLm+ftdp6o765y3Nba+ubxCgujrpvcpXb S1q2NubVfUqfXHW6ZPeT4TlOBocgXiK2pGFA1vVRXmR41SOdJcKUQqsRHJjmiGl2N9TI hp919CjZlMF6A0XzhVohf8guriXkOLLq219pDmkFIOGlqGrsbd9WgX7ZG/iZdUOFRCo7 +/h5q8G1i1AHHaxfFVyjedrNwqr8AiKSNdxWLiCuWTQOzqld+5g9A3/t6S7j1UC0ch4m vNK3aTSgPR5y+9Mn/tkZrCrf1nleEQHyu56aETMei6IPVbzqBWC3G7OKiYquPh3PZ/5t Rmtw== X-Gm-Message-State: AOAM530yZBKOBT84a1OwRIE8YE2WNg+4MDnPFLtn2lP0DgF33hWlTEdm lNf8YxM3Jm1g1/RAxNhI9w== X-Google-Smtp-Source: ABdhPJy9SCF44CcQJbSUiXgEkc9BHr7eeymXyPLB3zmBh4ucrhwiiARaLqeXVN83k3mcw0qJHmiSsg== X-Received: by 2002:a37:a3d2:0:b0:67b:30b2:732f with SMTP id m201-20020a37a3d2000000b0067b30b2732fmr21033089qke.719.1648578831377; Tue, 29 Mar 2022 11:33:51 -0700 (PDT) Received: from serve.minyard.net ([47.184.144.75]) by smtp.gmail.com with ESMTPSA id m4-20020ac85b04000000b002e1dcaed228sm15054133qtw.7.2022.03.29.11.33.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Mar 2022 11:33:49 -0700 (PDT) Sender: Corey Minyard Received: from t560.minyard.net (unknown [IPv6:2001:470:b8f6:1b:dcc2:ca6d:a437:b3e0]) by serve.minyard.net (Postfix) with ESMTPA id 0FA5D1817BF; Tue, 29 Mar 2022 18:33:48 +0000 (UTC) From: minyard@acm.org To: Chen Guanqiao Cc: openipmi-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org, Corey Minyard Subject: [PATCH 2/4] ipmi: Limit the number of message a user may have outstanding Date: Tue, 29 Mar 2022 13:33:38 -0500 Message-Id: <20220329183340.471474-3-minyard@acm.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220329183340.471474-1-minyard@acm.org> References: <20220329183340.471474-1-minyard@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Corey Minyard This way a rogue application can't use up a bunch of memory. Based on work by Chen Guanqiao Cc: Chen Guanqiao Signed-off-by: Corey Minyard --- drivers/char/ipmi/ipmi_msghandler.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index de80bf4c4e4c..2a05199e8224 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -151,6 +151,12 @@ module_param(max_users, uint, 0644); MODULE_PARM_DESC(max_users, "The most users that may use the IPMI stack at one time."); +/* The default maximum number of message a user may have outstanding. */ +static unsigned int max_msgs_per_user = 100; +module_param(max_msgs_per_user, uint, 0644); +MODULE_PARM_DESC(max_msgs_per_user, + "The most message a user may have outstanding."); + /* Call every ~1000 ms. */ #define IPMI_TIMEOUT_TIME 1000 @@ -193,6 +199,8 @@ struct ipmi_user { /* Does this interface receive IPMI events? */ bool gets_events; + atomic_t nr_msgs; + /* Free must run in process context for RCU cleanup. */ struct work_struct remove_work; }; @@ -934,11 +942,13 @@ static int deliver_response(struct ipmi_smi *intf, struct ipmi_recv_msg *msg) * risk. At this moment, simply skip it in that case. */ ipmi_free_recv_msg(msg); + atomic_dec(&msg->user->nr_msgs); } else { int index; struct ipmi_user *user = acquire_ipmi_user(msg->user, &index); if (user) { + atomic_dec(&user->nr_msgs); user->handler->ipmi_recv_hndl(msg, user->handler_data); release_ipmi_user(user, index); } else { @@ -1256,6 +1266,7 @@ int ipmi_create_user(unsigned int if_num, /* Note that each existing user holds a refcount to the interface. */ kref_get(&intf->refcount); + atomic_set(&new_user->nr_msgs, 0); kref_init(&new_user->refcount); new_user->handler = handler; new_user->handler_data = handler_data; @@ -2298,6 +2309,14 @@ static int i_ipmi_request(struct ipmi_user *user, struct ipmi_recv_msg *recv_msg; int rv = 0; + if (user) { + if (atomic_add_return(1, &user->nr_msgs) > max_msgs_per_user) { + atomic_dec(&user->nr_msgs); + rv = -EBUSY; + goto out; + } + } + if (supplied_recv) recv_msg = supplied_recv; else { @@ -2369,6 +2388,8 @@ static int i_ipmi_request(struct ipmi_user *user, rcu_read_unlock(); out: + if (rv && user) + atomic_dec(&user->nr_msgs); return rv; } -- 2.25.1