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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 44EC5C433FF for ; Fri, 9 Aug 2019 18:26:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27226214C6 for ; Fri, 9 Aug 2019 18:26:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407223AbfHIS0n (ORCPT ); Fri, 9 Aug 2019 14:26:43 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:44803 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726377AbfHIS0n (ORCPT ); Fri, 9 Aug 2019 14:26:43 -0400 Received: by mail-wr1-f68.google.com with SMTP id p17so99067673wrf.11 for ; Fri, 09 Aug 2019 11:26:42 -0700 (PDT) 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:subject:message-id:mime-version :content-disposition:user-agent; bh=B4KFIxKNutpA7/ftPIbvPrjeT2ChHpkvwQOhvlsGhS0=; b=otWzwfJqy997hCxwwTJobzJgu8yI9xh/GdtBAeNmWRIHUfAtYvFNL+CaY80tE8po3o cQImKd6jPgHYEYE28bSEHxw50vn70TVynX1lSywgLQhpHEV3wxRLjyqcuTboxMlXsiYh i0sIuTTkJk43dYuevg5FD76dYmyPiRFsp9P2e8EpnEV7lsN0CX6yUMx3xlnL/jyhcDcx 1Oai5gcXon2awoFhiU6nc+XDv9qG0tw8GfZLb655Te2IsO/879+PWYgnlPibq0EJmkeZ xASTW9vIZqtZpJa2CI4s43NpJmM+LgTY7/GHAbIpPyoALaExgv0viyvDF6T+sVw2nzna U9eg== X-Gm-Message-State: APjAAAXT6m3P9XcH9GHtauqholG+S6qZqZ3hBHHTMuIsctAulMFdT/CM qPnikEF93w5Vkv++GcIonL8= X-Google-Smtp-Source: APXvYqzDABIKO1iWibVTJYxknNES0RqfQYHlQQZNqCx7f0lvXtcgZJqIbqetoi4unazmQnRWCTWd0w== X-Received: by 2002:a5d:4602:: with SMTP id t2mr25459819wrq.340.1565375201482; Fri, 09 Aug 2019 11:26:41 -0700 (PDT) Received: from Nover ([161.105.209.130]) by smtp.gmail.com with ESMTPSA id e7sm4656455wmd.0.2019.08.09.11.26.41 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 09 Aug 2019 11:26:41 -0700 (PDT) Date: Fri, 9 Aug 2019 20:26:22 +0200 From: Paul Chaignon To: Kees Cook Cc: Andy Lutomirski , Will Drewry , linux-kernel@vger.kernel.org Subject: [PATCH] seccomp: allow BPF_MOD ALU instructions Message-ID: <20190809182621.GA4074@Nover> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We need BPF_MOD to match system calls against whitelists encoded as 32-bit bit arrays. The selection of the syscall's bit in the appropriate bit array requires a modulo operation such that X = 1 << nr % 32. Signed-off-by: Paul Chaignon --- kernel/seccomp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 811b4a86cdf6..87de6532ff6d 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -205,6 +205,8 @@ static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen) case BPF_ALU | BPF_MUL | BPF_X: case BPF_ALU | BPF_DIV | BPF_K: case BPF_ALU | BPF_DIV | BPF_X: + case BPF_ALU | BPF_MOD | BPF_K: + case BPF_ALU | BPF_MOD | BPF_X: case BPF_ALU | BPF_AND | BPF_K: case BPF_ALU | BPF_AND | BPF_X: case BPF_ALU | BPF_OR | BPF_K: -- 2.17.1