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=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 5F2A1C433E9 for ; Mon, 8 Feb 2021 15:20:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 255BC60238 for ; Mon, 8 Feb 2021 15:20:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233693AbhBHPUN (ORCPT ); Mon, 8 Feb 2021 10:20:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:58716 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231380AbhBHPN1 (ORCPT ); Mon, 8 Feb 2021 10:13:27 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 68B8764E37; Mon, 8 Feb 2021 15:09:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612796981; bh=R+xnOCzIiQN9x/XN1svdFYskdd1Vil8wXm37EY8P8tQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m2chrguVOa3bzuP+umVEERD8sknFee9ewrT8Q2NLM6nonUzquIOeRPgioVfzguLL2 wiIABI57FrJzXHPfL7WzCuYNjrIDRlsGe1QsIk+dkegGbYOWFgLncYTrrqVQw68wat WBKEyLLmkZdGUGafP+P7XX27PDbw05VXi0/yDn1k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Loris Reiff , Daniel Borkmann , Stanislav Fomichev , Sasha Levin Subject: [PATCH 5.4 08/65] bpf, cgroup: Fix optlen WARN_ON_ONCE toctou Date: Mon, 8 Feb 2021 16:00:40 +0100 Message-Id: <20210208145810.561571618@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210208145810.230485165@linuxfoundation.org> References: <20210208145810.230485165@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: stable@vger.kernel.org From: Loris Reiff [ Upstream commit bb8b81e396f7afbe7c50d789e2107512274d2a35 ] A toctou issue in `__cgroup_bpf_run_filter_getsockopt` can trigger a WARN_ON_ONCE in a check of `copy_from_user`. `*optlen` is checked to be non-negative in the individual getsockopt functions beforehand. Changing `*optlen` in a race to a negative value will result in a `copy_from_user(ctx.optval, optval, ctx.optlen)` with `ctx.optlen` being a negative integer. Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") Signed-off-by: Loris Reiff Signed-off-by: Daniel Borkmann Reviewed-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20210122164232.61770-1-loris.reiff@liblor.ch Signed-off-by: Sasha Levin --- kernel/bpf/cgroup.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 5a8b4dfdb1419..5b2413eb79db4 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -1109,6 +1109,11 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level, goto out; } + if (ctx.optlen < 0) { + ret = -EFAULT; + goto out; + } + if (copy_from_user(ctx.optval, optval, min(ctx.optlen, max_optlen)) != 0) { ret = -EFAULT; -- 2.27.0