From patchwork Mon Sep 21 12:12:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenz Bauer X-Patchwork-Id: 1368320 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=cloudflare.com header.i=@cloudflare.com header.a=rsa-sha256 header.s=google header.b=BUKKdNfh; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4Bw3J85y7gz9sTW for ; Mon, 21 Sep 2020 22:13:44 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726818AbgIUMN3 (ORCPT ); Mon, 21 Sep 2020 08:13:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726756AbgIUMNY (ORCPT ); Mon, 21 Sep 2020 08:13:24 -0400 Received: from mail-wm1-x343.google.com (mail-wm1-x343.google.com [IPv6:2a00:1450:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABB34C0613D1 for ; Mon, 21 Sep 2020 05:13:22 -0700 (PDT) Received: by mail-wm1-x343.google.com with SMTP id y15so12401327wmi.0 for ; Mon, 21 Sep 2020 05:13:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ReOPTCTBI89zUNcN9aZJisi4S7TTo39X4bWkAmOczYk=; b=BUKKdNfhkrFr8+QFBgF7oDEnyUFywcrt2x94/PKwiJtYV+CKEv97YK+TKZOdy94ANZ kjKQ1kurSlIpzVE+/9slxlPmChzWtyF8O83ui1P4zddpJ0DvTE/VJjIGzRCQoev3guAX 8L3+UmZXUQyI7//JYub1n/o3CBB4S7P7nkGJY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ReOPTCTBI89zUNcN9aZJisi4S7TTo39X4bWkAmOczYk=; b=EE/u89M1o3QIYnN72lnRgM4nopOFJduXiQEO4vE+TRLUKVH4y2VjmQ3nR+69vzI6rg umL3eaiENcgr+e9j3FniwbEoAAGZYvN8u4xAihm5HBNXW5YMweB5G1d1BDbXux7fNEf6 VBEWbm8DE/XAlV9morNNbukPGB36o4n2pNTfmUcecqvqq1QTHe0YGpK0qNnzHse+b+UG NGfQ1XZMcbbaa/yAhlgNGtVw6flykfdoocVjuLyT4/mjao2KvRN99FA5DECYH346auac H3eIH65XAVFbr7lM73fOyu06tbFLFTIFX8Qg9W0bTOfuLzy4vECFbjMM+JqC/9CWip9f Z22w== X-Gm-Message-State: AOAM531LoVPUSsr1JkDdrG11CyPNxmsBkCfS8zzQWi4rM35mtkITPoBC Uf8KzyZs2ZU/I0Ws+MJ2f5Ui17ysZHdxBw== X-Google-Smtp-Source: ABdhPJzl/LJ/BwumR/eFyLYdKcUTfD8bMu+ABbnSiTZH9KhFmUJRtjXHa0O5fbPkcUWdj29WprB7Dw== X-Received: by 2002:a1c:3d44:: with SMTP id k65mr29025265wma.132.1600690401340; Mon, 21 Sep 2020 05:13:21 -0700 (PDT) Received: from antares.lan (5.4.6.2.d.5.3.3.f.8.1.6.b.2.d.8.f.f.6.2.a.5.a.7.0.b.8.0.1.0.0.2.ip6.arpa. [2001:8b0:7a5a:26ff:8d2b:618f:335d:2645]) by smtp.gmail.com with ESMTPSA id t15sm18466557wmj.15.2020.09.21.05.13.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Sep 2020 05:13:20 -0700 (PDT) From: Lorenz Bauer To: ast@kernel.org, daniel@iogearbox.net Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, Lorenz Bauer , Martin KaFai Lau Subject: [PATCH bpf-next v4 05/11] bpf: make BTF pointer type checking generic Date: Mon, 21 Sep 2020 13:12:21 +0100 Message-Id: <20200921121227.255763-6-lmb@cloudflare.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200921121227.255763-1-lmb@cloudflare.com> References: <20200921121227.255763-1-lmb@cloudflare.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Perform BTF type checks if the register we're working on contains a BTF pointer, rather than if the argument is for a BTF pointer. This is easier to understand, and allows removing the code from the arg_type checking section of the function. Signed-off-by: Lorenz Bauer Acked-by: Martin KaFai Lau --- kernel/bpf/verifier.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9f95d6d55c5f..99c0d7adcb1e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4001,27 +4001,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, goto err_type; } } else if (arg_type == ARG_PTR_TO_BTF_ID) { - const u32 *btf_id = fn->arg_btf_id[arg]; - expected_type = PTR_TO_BTF_ID; if (type != expected_type) goto err_type; - - if (!btf_id) { - verbose(env, "verifier internal error: missing BTF ID\n"); - return -EFAULT; - } - - if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, *btf_id)) { - verbose(env, "R%d is of type %s but %s is expected\n", - regno, kernel_type_name(reg->btf_id), kernel_type_name(*btf_id)); - return -EACCES; - } - if (!tnum_is_const(reg->var_off) || reg->var_off.value) { - verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", - regno); - return -EACCES; - } } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { if (meta->func_id == BPF_FUNC_spin_lock) { if (process_spin_lock(env, regno, true)) @@ -4076,6 +4058,26 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, return -EFAULT; } + if (type == PTR_TO_BTF_ID) { + const u32 *btf_id = fn->arg_btf_id[arg]; + + if (!btf_id) { + verbose(env, "verifier internal error: missing BTF ID\n"); + return -EFAULT; + } + + if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, *btf_id)) { + verbose(env, "R%d is of type %s but %s is expected\n", + regno, kernel_type_name(reg->btf_id), kernel_type_name(*btf_id)); + return -EACCES; + } + if (!tnum_is_const(reg->var_off) || reg->var_off.value) { + verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", + regno); + return -EACCES; + } + } + if (arg_type == ARG_CONST_MAP_PTR) { /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ meta->map_ptr = reg->map_ptr;