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=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 DC67CC433E0 for ; Thu, 11 Feb 2021 16:16:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A141764E7A for ; Thu, 11 Feb 2021 16:16:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231256AbhBKQPg (ORCPT ); Thu, 11 Feb 2021 11:15:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:53524 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230436AbhBKPWi (ORCPT ); Thu, 11 Feb 2021 10:22:38 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1B2D764F38; Thu, 11 Feb 2021 15:07:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613056043; bh=Gyko2fH262bh7ohxuvJOx5kBhTezFJQX5eqq9T8pDbo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ISDQ8ZBLr3S6lWnDEp8UkG9Y2bQXxhvjFrN78AiTNVzBOIcj1lNP/p/Qp0ShvYzJJ Crr7EK8Xuzfpt2CC2Mne8AlR9jxfbGjQpes3h8/LtcWjWl5WFWbmAnKCCdUuoePkN5 0O1RUcH1tQWb5qg3BlHq3VGEmcwK0IHE93kg2rr4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+b2bf2652983d23734c5c@syzkaller.appspotmail.com, Steffen Klassert , Herbert Xu , Cong Wang , Sasha Levin Subject: [PATCH 4.19 06/24] af_key: relax availability checks for skb size calculation Date: Thu, 11 Feb 2021 16:02:40 +0100 Message-Id: <20210211150148.026903055@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210211150147.743660073@linuxfoundation.org> References: <20210211150147.743660073@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Cong Wang [ Upstream commit afbc293add6466f8f3f0c3d944d85f53709c170f ] xfrm_probe_algs() probes kernel crypto modules and changes the availability of struct xfrm_algo_desc. But there is a small window where ealg->available and aalg->available get changed between count_ah_combs()/count_esp_combs() and dump_ah_combs()/dump_esp_combs(), in this case we may allocate a smaller skb but later put a larger amount of data and trigger the panic in skb_put(). Fix this by relaxing the checks when counting the size, that is, skipping the test of ->available. We may waste some memory for a few of sizeof(struct sadb_comb), but it is still much better than a panic. Reported-by: syzbot+b2bf2652983d23734c5c@syzkaller.appspotmail.com Cc: Steffen Klassert Cc: Herbert Xu Signed-off-by: Cong Wang Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin --- net/key/af_key.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/key/af_key.c b/net/key/af_key.c index e340e97224c3a..c7d5a6015389b 100644 --- a/net/key/af_key.c +++ b/net/key/af_key.c @@ -2908,7 +2908,7 @@ static int count_ah_combs(const struct xfrm_tmpl *t) break; if (!aalg->pfkey_supported) continue; - if (aalg_tmpl_set(t, aalg) && aalg->available) + if (aalg_tmpl_set(t, aalg)) sz += sizeof(struct sadb_comb); } return sz + sizeof(struct sadb_prop); @@ -2926,7 +2926,7 @@ static int count_esp_combs(const struct xfrm_tmpl *t) if (!ealg->pfkey_supported) continue; - if (!(ealg_tmpl_set(t, ealg) && ealg->available)) + if (!(ealg_tmpl_set(t, ealg))) continue; for (k = 1; ; k++) { @@ -2937,7 +2937,7 @@ static int count_esp_combs(const struct xfrm_tmpl *t) if (!aalg->pfkey_supported) continue; - if (aalg_tmpl_set(t, aalg) && aalg->available) + if (aalg_tmpl_set(t, aalg)) sz += sizeof(struct sadb_comb); } } -- 2.27.0