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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, 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 92F78C07E9C for ; Mon, 5 Jul 2021 16:28:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71E9A6135D for ; Mon, 5 Jul 2021 16:28:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229495AbhGEQag (ORCPT ); Mon, 5 Jul 2021 12:30:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229560AbhGEQag (ORCPT ); Mon, 5 Jul 2021 12:30:36 -0400 Received: from mail-il1-x132.google.com (mail-il1-x132.google.com [IPv6:2607:f8b0:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46949C06175F; Mon, 5 Jul 2021 09:27:58 -0700 (PDT) Received: by mail-il1-x132.google.com with SMTP id j12so6901929ils.5; Mon, 05 Jul 2021 09:27:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-transfer-encoding; bh=6mm4TwDU0EQC4agqLfuyOy/11Do/Eo/Z1FMIy3HRwDs=; b=tOBTqp0R/XjqjIl9ln0thxQKVYHhzL4FMlK8KWgTDzpu35zB6sFro5jHBTZLBdI63/ BhcCKDTaaTFgnrvxn3WrFf0hG+wqd8V5WSk/lUGEAk2EZYN633ZFodbXXh3s+2Dt/VNK zQy6/WAKuv/trUi5xiVO1W94jK+h4idpn9JHU0qKMtprPTZYeYnUqEhiJ4prW6rRPQWa yfe1wQ2shP26u/j6SvWI8j7Ycy5ZPYCjNyXJlKtNU4oUQWdmjl0UlpEe5FYgJQrOTqeV f/Spx25fdneBKqeZDzPECPzKSNPCX6CpYTi7wkGafmQP1uXlbnFrWzqrip8rB4cRlKPt FpKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-transfer-encoding; bh=6mm4TwDU0EQC4agqLfuyOy/11Do/Eo/Z1FMIy3HRwDs=; b=iq+jIBaP9g+nzPvMv5RV7q5oTrNDij3aRgDIpjpSnr7x/8Yne+YjKzlJzG9x2WsSLH L9tmebHjWTcb6lk8DE7fBWOCb7sfASP7NNjIWNoKfax8HiG1jzlcdEQ3ShDe5IhM7nb/ OEMWrCnNtOED+9O5Pmg3lfo3w4AgshKLFOr2ittEkqHaFLxNLzDnFLUgrmXxa1G2/1Po 9uBZuSdpyFajsCAxz1eZlWaqvzLBCoRsGAWxTrnj2KGjEO/KWJmUPPNC5GPmhPhMUhU9 UfuOZEc2VYXXFh51irk+RLiy5npaqNC0PXhXj6TLjcqukbkVDp6lNCAw/fembdaNZRAR AeXw== X-Gm-Message-State: AOAM532PRGfAiYhqfO8DMWbgq+1gvv6mvkNVXkdVug0Arndb9/9AOug5 mc06//NfNp9YmiABkf+tk4g= X-Google-Smtp-Source: ABdhPJzpK4aY4Efpw/Vbf7XI2wObiBt8q6IWrhM/TfVFTkS5KFKe8YRzjEmet+YgWCo9gT2S3n7Jhw== X-Received: by 2002:a05:6e02:b4c:: with SMTP id f12mr11145321ilu.214.1625502477198; Mon, 05 Jul 2021 09:27:57 -0700 (PDT) Received: from localhost ([172.243.157.240]) by smtp.gmail.com with ESMTPSA id c23sm7202327ioz.42.2021.07.05.09.27.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Jul 2021 09:27:56 -0700 (PDT) Date: Mon, 05 Jul 2021 09:27:49 -0700 From: John Fastabend To: Cong Wang , John Fastabend Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , bpf , Linux Kernel Network Developers Message-ID: <60e333051eb3d_20ea20862@john-XPS-13-9370.notmuch> In-Reply-To: References: <20210702001123.728035-1-john.fastabend@gmail.com> <20210702001123.728035-2-john.fastabend@gmail.com> Subject: Re: [PATCH v2 bpf 1/2] bpf, sockmap: fix potential msg memory leak Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Cong Wang wrote: > On Thu, Jul 1, 2021 at 5:12 PM John Fastabend wrote: > > > > If skb_linearize is needed and fails we could leak a msg on the error > > handling. To fix ensure we kfree the msg block before returning error. > > Found during code review. > > > > Fixes: 4363023d2668e ("bpf, sockmap: Avoid failures from skb_to_sgvec when skb has frag_list") > > Signed-off-by: John Fastabend > > --- > > net/core/skmsg.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/net/core/skmsg.c b/net/core/skmsg.c > > index 9b6160a191f8..22603289c2b2 100644 > > --- a/net/core/skmsg.c > > +++ b/net/core/skmsg.c > > @@ -505,8 +505,10 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb, > > * drop the skb. We need to linearize the skb so that the mapping > > * in skb_to_sgvec can not error. > > */ > > - if (skb_linearize(skb)) > > + if (skb_linearize(skb)) { > > + kfree(msg); > > return -EAGAIN; > > + } > > num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len); > > if (unlikely(num_sge < 0)) { > > kfree(msg); > > I think it is better to let whoever allocates msg free it, IOW, > let sk_psock_skb_ingress_enqueue()'s callers handle its failure. Sure, although we already have the one kfree(msg) below. Anyways I'll just move these back a bit. Agree it is slightly nicer. Thanks.