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=-18.9 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 7D1AAC47082 for ; Tue, 8 Jun 2021 18:34:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67E5561436 for ; Tue, 8 Jun 2021 18:34:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234264AbhFHSgo (ORCPT ); Tue, 8 Jun 2021 14:36:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:57310 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234388AbhFHSem (ORCPT ); Tue, 8 Jun 2021 14:34:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DA17C613B9; Tue, 8 Jun 2021 18:31:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623177114; bh=YWx7Wpz/nixlUUeiM88xb7Aa0wPZrmfma7RLTzvvMLI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bxEob4yHrTq6Xh47BrOw1xgQoLdlesewW0tYy64MBThemc3fwfJFw6gIsxgztVuSw 9rE1JhH6/Qde7B+aL0CNzfAN3PHUfE/6M1g0WGUDM0LMH9u7SZbMFCwztdh3ksYL5M eriaeLEuH7mIvn4VNyUh1H+ev0xuel5AxgUUEHCc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Jann Horn , Daniel Borkmann , Alexei Starovoitov , Frank van der Linden Subject: [PATCH 4.14 37/47] bpf/verifier: disallow pointer subtraction Date: Tue, 8 Jun 2021 20:27:20 +0200 Message-Id: <20210608175931.695295703@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210608175930.477274100@linuxfoundation.org> References: <20210608175930.477274100@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: 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 Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2754,7 +2754,7 @@ static int adjust_reg_min_max_vals(struc * 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; }