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=-19.1 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_NONE, 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 6B0D0C47099 for ; Mon, 31 May 2021 18:26:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5635E60720 for ; Mon, 31 May 2021 18:26:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232185AbhEaS2B (ORCPT ); Mon, 31 May 2021 14:28:01 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:15521 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232106AbhEaS1k (ORCPT ); Mon, 31 May 2021 14:27:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1622485560; x=1654021560; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=6Ujhe1o2//t2sL/Bdme2bYabu2VD1SRC6if9ge9pPb4=; b=wFT4XMy659rPn3XGWQ8xXC9yRMOy9sRMYvYzaphOvwtaCryw2ipeErOZ hQdgmUU6/iSH7s32ishv5KHilH1D4NM3IeGQUkqETp5ltyQwt4kRynHCS IAYs+1ogUlFGOQQi5gAaejZ1p7dRlB18et8pDDyyf2/pgK2y75yKp/AZh E=; X-IronPort-AV: E=Sophos;i="5.83,238,1616457600"; d="scan'208";a="117089370" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1d-474bcd9f.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-6001.iad6.amazon.com with ESMTP; 31 May 2021 18:25:59 +0000 Received: from EX13MTAUWA001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1d-474bcd9f.us-east-1.amazon.com (Postfix) with ESMTPS id C5DBBA1B29; Mon, 31 May 2021 18:25:58 +0000 (UTC) Received: from EX13D48UWA003.ant.amazon.com (10.43.163.4) by EX13MTAUWA001.ant.amazon.com (10.43.160.58) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Mon, 31 May 2021 18:25:58 +0000 Received: from EX13MTAUWA001.ant.amazon.com (10.43.160.58) by EX13D48UWA003.ant.amazon.com (10.43.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Mon, 31 May 2021 18:25:58 +0000 Received: from dev-dsk-fllinden-2c-d7720709.us-west-2.amazon.com (172.19.206.175) by mail-relay.amazon.com (10.43.160.118) with Microsoft SMTP Server id 15.0.1497.18 via Frontend Transport; Mon, 31 May 2021 18:25:58 +0000 Received: by dev-dsk-fllinden-2c-d7720709.us-west-2.amazon.com (Postfix, from userid 6262777) id 907691F4; Mon, 31 May 2021 18:25:57 +0000 (UTC) From: Frank van der Linden To: CC: , Subject: [PATCH v2 4.14 11/17] bpf/verifier: disallow pointer subtraction Date: Mon, 31 May 2021 18:25:50 +0000 Message-ID: <20210531182556.25277-12-fllinden@amazon.com> X-Mailer: git-send-email 2.23.4 In-Reply-To: <20210531182556.25277-1-fllinden@amazon.com> References: <20210531182556.25277-1-fllinden@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Alexei Starovoitov commit dd066823db2ac4e22f721ec85190817b58059a54 upstream. Subtraction of pointers was accidentally allowed for unpriv programs by commit 82abbf8d2fc4. Revert that part of commit. Fixes: 82abbf8d2fc4 ("bpf: do not allow root to mangle valid pointers") Reported-by: Jann Horn Acked-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann [fllinden@amazon.com: backport to 4.14] Signed-off-by: Frank van der Linden --- kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b999e268ee23..5c440398e0a1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2754,7 +2754,7 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, * an arbitrary scalar. Disallow all math except * pointer subtraction */ - if (opcode == BPF_SUB){ + if (opcode == BPF_SUB && env->allow_ptr_leaks) { mark_reg_unknown(regs, insn->dst_reg); return 0; } -- 2.23.4