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=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 4AB5BC47083 for ; Mon, 31 May 2021 18:26:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D06C6127C for ; Mon, 31 May 2021 18:26:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232805AbhEaS2D (ORCPT ); Mon, 31 May 2021 14:28:03 -0400 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:15297 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232258AbhEaS1k (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=1622485561; x=1654021561; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=7I/u3nHbWmsJVriEmtpLNUmicvltO83+/vXERrpO1YA=; b=ipdiKlGbFkdcNGiP6DUEMk6qVh+VcRcIxcSsfFVK9WN+F64bpQtJsYnf VAjvDHgSonqfN4Iffmrc8+PakPtjDiG/GX65zTGuhLE0DT2IbO9r9HqJ/ tHiU5QcIsLgPwOBicQvZK1kfKFKS1c7ksdJ00Bz9vNpSryo30Dm+jIR7W E=; X-IronPort-AV: E=Sophos;i="5.83,238,1616457600"; d="scan'208";a="137675707" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-1e-a70de69e.us-east-1.amazon.com) ([10.25.36.210]) by smtp-border-fw-9102.sea19.amazon.com with ESMTP; 31 May 2021 18:26:00 +0000 Received: from EX13MTAUWB001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1e-a70de69e.us-east-1.amazon.com (Postfix) with ESMTPS id A0E39A0480; Mon, 31 May 2021 18:25:58 +0000 (UTC) Received: from EX13D15UWB003.ant.amazon.com (10.43.161.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.207) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Mon, 31 May 2021 18:25:58 +0000 Received: from EX13MTAUWB001.ant.amazon.com (10.43.161.207) by EX13D15UWB003.ant.amazon.com (10.43.161.138) 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 (10.43.161.249) with Microsoft SMTP Server id 15.0.1497.18 via Frontend Transport; Mon, 31 May 2021 18:25:57 +0000 Received: by dev-dsk-fllinden-2c-d7720709.us-west-2.amazon.com (Postfix, from userid 6262777) id 8F45B149A; Mon, 31 May 2021 18:25:57 +0000 (UTC) From: Frank van der Linden To: CC: , Subject: [PATCH v2 4.14 04/17] bpf: Rework ptr_limit into alu_limit and add common error path Date: Mon, 31 May 2021 18:25:43 +0000 Message-ID: <20210531182556.25277-5-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: Daniel Borkmann commit b658bbb844e28f1862867f37e8ca11a8e2aa94a3 upstream. 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 9cb2c035f06d..12cb6b1c4e9b 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, -- 2.23.4