From patchwork Fri Apr 5 19:35:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Ignatov X-Patchwork-Id: 1078678 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=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="euAJzk7c"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44bVTT6kBDz9sST for ; Sat, 6 Apr 2019 06:37:49 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732038AbfDEThB (ORCPT ); Fri, 5 Apr 2019 15:37:01 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:34188 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732028AbfDEThA (ORCPT ); Fri, 5 Apr 2019 15:37:00 -0400 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.27/8.16.0.27) with SMTP id x35Jatld015833 for ; Fri, 5 Apr 2019 12:36:59 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=cxdmKji8Yh7fIjPXx1c0mYfiywZ72tTdA4s4N8tQkRE=; b=euAJzk7cdO4qOMfk2BxDwPaye4Xg6feF46BfBQHzABlj5lIsfNO61ZcOIloNOANHbdbK zadRx1mVS3n62atwqlcsHPXdgAzKwEJOYIYrBOHcN7P/Y8crNh1nioW3WVu0zRwnh/4f 08uvpDXAAH6lkghRdcDIdO2Ct00saC5sfgY= Received: from maileast.thefacebook.com ([199.201.65.23]) by m0089730.ppops.net with ESMTP id 2rpchfr61y-12 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Fri, 05 Apr 2019 12:36:59 -0700 Received: from mx-out.facebook.com (2620:10d:c0a1:3::13) by mail.thefacebook.com (2620:10d:c021:18::172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Fri, 5 Apr 2019 12:36:53 -0700 Received: by dev082.prn2.facebook.com (Postfix, from userid 572249) id 0167C3701752; Fri, 5 Apr 2019 12:36:51 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrey Ignatov Smtp-Origin-Hostname: dev082.prn2.facebook.com To: CC: Andrey Ignatov , , , , , Luis Chamberlain , Kees Cook , Alexey Dobriyan , , Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v3 bpf-next 15/21] bpf: Introduce ARG_PTR_TO_{INT, LONG} arg types Date: Fri, 5 Apr 2019 12:35:37 -0700 Message-ID: <7f6dd906560abf1fa0fb746bd19cd20760c63e9e.1554485410.git.rdna@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-04-05_15:, , signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Currently the way to pass result from BPF helper to BPF program is to provide memory area defined by pointer and size: func(void *, size_t). It works great for generic use-case, but for simple types, such as int, it's overkill and consumes two arguments when it could use just one. Introduce new argument types ARG_PTR_TO_INT and ARG_PTR_TO_LONG to be able to pass result from helper to program via pointer to int and long correspondingly: func(int *) or func(long *). New argument types are similar to ARG_PTR_TO_MEM with the following differences: * they don't require corresponding ARG_CONST_SIZE argument, predefined access sizes are used instead (32bit for int, 64bit for long); * it's possible to use more than one such an argument in a helper; * provided pointers have to be aligned. It's easy to introduce similar ARG_PTR_TO_CHAR and ARG_PTR_TO_SHORT argument types. It's not done due to lack of use-case though. Signed-off-by: Andrey Ignatov --- include/linux/bpf.h | 2 ++ kernel/bpf/verifier.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a445194b5fb6..986f89d9de63 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -195,6 +195,8 @@ enum bpf_arg_type { ARG_ANYTHING, /* any (initialized) argument is ok */ ARG_PTR_TO_SPIN_LOCK, /* pointer to bpf_spin_lock */ ARG_PTR_TO_SOCK_COMMON, /* pointer to sock_common */ + ARG_PTR_TO_INT, /* pointer to int */ + ARG_PTR_TO_LONG, /* pointer to long */ }; /* type of values returned from helper functions */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 56baf21b57c2..6ff5c0e048b1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2433,6 +2433,22 @@ static bool arg_type_is_mem_size(enum bpf_arg_type type) type == ARG_CONST_SIZE_OR_ZERO; } +static bool arg_type_is_int_ptr(enum bpf_arg_type type) +{ + return type == ARG_PTR_TO_INT || + type == ARG_PTR_TO_LONG; +} + +static int int_ptr_type_to_size(enum bpf_arg_type type) +{ + if (type == ARG_PTR_TO_INT) + return sizeof(u32); + else if (type == ARG_PTR_TO_LONG) + return sizeof(u64); + + return -EINVAL; +} + static int check_func_arg(struct bpf_verifier_env *env, u32 regno, enum bpf_arg_type arg_type, struct bpf_call_arg_meta *meta) @@ -2525,6 +2541,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, type != expected_type) goto err_type; meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM; + } else if (arg_type_is_int_ptr(arg_type)) { + expected_type = PTR_TO_STACK; + if (!type_is_pkt_pointer(type) && + type != PTR_TO_MAP_VALUE && + type != expected_type) + goto err_type; } else { verbose(env, "unsupported arg_type %d\n", arg_type); return -EFAULT; @@ -2606,6 +2628,13 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, err = check_helper_mem_access(env, regno - 1, reg->umax_value, zero_size_allowed, meta); + } else if (arg_type_is_int_ptr(arg_type)) { + int size = int_ptr_type_to_size(arg_type); + + err = check_helper_mem_access(env, regno, size, false, meta); + if (err) + return err; + err = check_ptr_alignment(env, reg, 0, size, true); } return err;