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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7066AC433B4 for ; Mon, 12 Apr 2021 09:01:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4700D61262 for ; Mon, 12 Apr 2021 09:01:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238824AbhDLJCE (ORCPT ); Mon, 12 Apr 2021 05:02:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239059AbhDLI7F (ORCPT ); Mon, 12 Apr 2021 04:59:05 -0400 Received: from mail-lf1-x130.google.com (mail-lf1-x130.google.com [IPv6:2a00:1450:4864:20::130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12A9DC06138D for ; Mon, 12 Apr 2021 01:56:50 -0700 (PDT) Received: by mail-lf1-x130.google.com with SMTP id n8so20188276lfh.1 for ; Mon, 12 Apr 2021 01:56:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version; bh=v80JJJDW9QtxHkk0a0zU0nnrThIy25/WR2Z0y5oalCQ=; b=B0FICsUZf5BlugUzF6HFNlkL5xjsucp0vP8Ze+uCdd+R0swzQwgQoJXK+CzHNwyYps Idg6A81UHoPEHV2+aO2VHh1yzZWxUDXt0M2lvIN+6AGXURRcLwc18alykY183arV+jv0 gtKBn//eU/Vh3G5BzOFRBljiadmr8pZ/Oab80= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version; bh=v80JJJDW9QtxHkk0a0zU0nnrThIy25/WR2Z0y5oalCQ=; b=nc7+ux8U6pcqRAVUUxQkGZ9X0YxsbAIUWv0kBcmp7mR3MYW8M3gJNyhPPIDzlaOFok b7yXC/SD/lsQ26+q/4Kxifs6tlbFv0eJfkKk997Cig8J82eg22nctEzSYd0orPG5Ggnc 6WlE0NE1PnPhIolj/Kgwopsea82mcA4zM9xuEnrkgVp/5Q59kTl5dXSik4xmQUswipFQ 74niKVCosRsFh2/pdS4MxofKsQ0izMfvkbczmuigbt+1W7oYNrMAK5NFYyM12hdtk5/N kCTen6mRMOQcopXFQDTzts8BnYQVhGraPpNFzJ8187e+f5Qy1v6jVbe0W3aTy6mPGfE7 xw+Q== X-Gm-Message-State: AOAM530nBPQ9MyJWFvBdtqXWJIr4OPSILbAAhDESoZ9IJn+dHy1w9GOY q7rkhZrXLvD448gw87bwx9Ae9g== X-Google-Smtp-Source: ABdhPJzS8q80Ofl+UQJgn2PmQRSlB7aoaXgbZM87nPxi9zU3guOvIdL4NtCaH8vS1B7vmXTmlb/huA== X-Received: by 2002:ac2:5617:: with SMTP id v23mr18500507lfd.123.1618217808502; Mon, 12 Apr 2021 01:56:48 -0700 (PDT) Received: from cloudflare.com (79.184.75.85.ipv4.supernova.orange.pl. [79.184.75.85]) by smtp.gmail.com with ESMTPSA id y25sm2739125ljc.73.2021.04.12.01.56.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Apr 2021 01:56:47 -0700 (PDT) References: <20210408030556.45134-1-xiyou.wangcong@gmail.com> User-agent: mu4e 1.1.0; emacs 27.1 From: Jakub Sitnicki To: Cong Wang Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Cong Wang , syzbot+7b6548ae483d6f4c64ae@syzkaller.appspotmail.com, John Fastabend , Daniel Borkmann , Lorenz Bauer Subject: Re: [Patch bpf-next] sock_map: fix a potential use-after-free in sock_map_close() In-reply-to: <20210408030556.45134-1-xiyou.wangcong@gmail.com> Date: Mon, 12 Apr 2021 10:56:46 +0200 Message-ID: <87pmyz3mpd.fsf@cloudflare.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Apr 08, 2021 at 05:05 AM CEST, Cong Wang wrote: > From: Cong Wang > > The last refcnt of the psock can be gone right after > sock_map_remove_links(), so sk_psock_stop() could trigger a UAF. > The reason why I placed sk_psock_stop() there is to avoid RCU read > critical section, and more importantly, some callee of > sock_map_remove_links() is supposed to be called with RCU read lock, > we can not simply get rid of RCU read lock here. Therefore, the only > choice we have is to grab an additional refcnt with sk_psock_get() > and put it back after sk_psock_stop(). > > Reported-by: syzbot+7b6548ae483d6f4c64ae@syzkaller.appspotmail.com > Fixes: 799aa7f98d53 ("skmsg: Avoid lock_sock() in sk_psock_backlog()") > Cc: John Fastabend > Cc: Daniel Borkmann > Cc: Jakub Sitnicki > Cc: Lorenz Bauer > Signed-off-by: Cong Wang > --- Acked-by: Jakub Sitnicki