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=-19.0 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 9A3CFC433ED for ; Sat, 1 May 2021 04:30:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82DC161208 for ; Sat, 1 May 2021 04:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231495AbhEAEb3 (ORCPT ); Sat, 1 May 2021 00:31:29 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:40757 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231455AbhEAEb3 (ORCPT ); Sat, 1 May 2021 00:31:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1619843441; x=1651379441; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=kNNJJSSd6K61oftW+z6W77QvbDWXihC7bR0XoyLjC0w=; b=P9+c8/tBivbVydI/AOBIYKuHJpalg53u7UzUhrm7i+Rx0+j9e0CI3KaQ EJzDN+bikeUajpj+B6Y8O+uHsG6RVWYLWGKD+lvfluE5P6/pUARavp/Dk /nkcNDmp6BIEV80HDTEJHt5aeT6aUBlJlmDQNpvDfC2gkIWdY7+Wzuzu+ s=; X-IronPort-AV: E=Sophos;i="5.82,264,1613433600"; d="scan'208";a="110970711" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-41350382.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-6001.iad6.amazon.com with ESMTP; 01 May 2021 04:30:39 +0000 Received: from EX13MTAUWA001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-2a-41350382.us-west-2.amazon.com (Postfix) with ESMTPS id 473B4C0042; Sat, 1 May 2021 04:30:38 +0000 (UTC) Received: from EX13D01UWA004.ant.amazon.com (10.43.160.99) by EX13MTAUWA001.ant.amazon.com (10.43.160.58) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 1 May 2021 04:30:23 +0000 Received: from EX13MTAUEB002.ant.amazon.com (10.43.60.12) by EX13d01UWA004.ant.amazon.com (10.43.160.99) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 1 May 2021 04:30:22 +0000 Received: from dev-dsk-fllinden-2c-d7720709.us-west-2.amazon.com (172.19.206.175) by mail-relay.amazon.com (10.43.60.234) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Sat, 1 May 2021 04:30:14 +0000 Received: by dev-dsk-fllinden-2c-d7720709.us-west-2.amazon.com (Postfix, from userid 6262777) id 403D0978; Sat, 1 May 2021 04:30:14 +0000 (UTC) From: Frank van der Linden To: CC: , , , , , Subject: [PATCH 4.14 06/15] bpf: Rework ptr_limit into alu_limit and add common error path Date: Sat, 1 May 2021 04:30:05 +0000 Message-ID: <20210501043014.33300-7-fllinden@amazon.com> X-Mailer: git-send-email 2.23.4 In-Reply-To: <20210501043014.33300-1-fllinden@amazon.com> References: <20210501043014.33300-1-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: Daniel Borkmann Upstream commit b658bbb844e28f1862867f37e8ca11a8e2aa94a3 Small refactor with no semantic changes in order to consolidate the max ptr_limit boundary check. Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Acked-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b06de3d8facf..ef1fe213cbce 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2026,12 +2026,12 @@ static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env) static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, const struct bpf_reg_state *off_reg, - u32 *ptr_limit, u8 opcode) + u32 *alu_limit, u8 opcode) { bool off_is_neg = off_reg->smin_value < 0; bool mask_to_left = (opcode == BPF_ADD && off_is_neg) || (opcode == BPF_SUB && !off_is_neg); - u32 off, max; + u32 off, max = 0, ptr_limit = 0; if (!tnum_is_const(off_reg->var_off) && (off_reg->smin_value < 0) != (off_reg->smax_value < 0)) @@ -2045,22 +2045,27 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, max = MAX_BPF_STACK + mask_to_left; off = ptr_reg->off + ptr_reg->var_off.value; if (mask_to_left) - *ptr_limit = MAX_BPF_STACK + off; + ptr_limit = MAX_BPF_STACK + off; else - *ptr_limit = -off - 1; - return *ptr_limit >= max ? -ERANGE : 0; + ptr_limit = -off - 1; + break; case PTR_TO_MAP_VALUE: max = ptr_reg->map_ptr->value_size; if (mask_to_left) { - *ptr_limit = ptr_reg->umax_value + ptr_reg->off; + ptr_limit = ptr_reg->umax_value + ptr_reg->off; } else { off = ptr_reg->smin_value + ptr_reg->off; - *ptr_limit = ptr_reg->map_ptr->value_size - off - 1; + ptr_limit = ptr_reg->map_ptr->value_size - off - 1; } - return *ptr_limit >= max ? -ERANGE : 0; + break; default: return -EINVAL; } + + if (ptr_limit >= max) + return -ERANGE; + *alu_limit = ptr_limit; + return 0; } static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env, -- 2.23.3