From patchwork Fri Mar 29 01:01:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Ignatov X-Patchwork-Id: 1068937 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="iZ1vqzQg"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44Vk3k58llz9sSf for ; Fri, 29 Mar 2019 12:02:26 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728650AbfC2BCZ (ORCPT ); Thu, 28 Mar 2019 21:02:25 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:46574 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728027AbfC2BCY (ORCPT ); Thu, 28 Mar 2019 21:02:24 -0400 Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x2T0wqN5017591 for ; Thu, 28 Mar 2019 18:02:23 -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=23XbIQepTMCZAQvZPKGtPCBpNO0fKcMGGscSDkW0LoE=; b=iZ1vqzQg6mbGYa2qoLfnfiBR7FL1LhwuJBOl+YPcr9rmndc5Y0Yg/ORwBfb4YYJc0/nK fXmMzp+G3B9iRYSwPjy/SS+HUHl+nQO1h2b7pwvKCBmBGbF5slUR1Sl5F82bgPTjKH2X yn6Dz6tP7lmWojRVUDejwa5xY33EZY+xLfw= Received: from maileast.thefacebook.com ([199.201.65.23]) by mx0a-00082601.pphosted.com with ESMTP id 2rh3ya1juh-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Thu, 28 Mar 2019 18:02:23 -0700 Received: from mx-out.facebook.com (2620:10d:c0a1:3::13) by mail.thefacebook.com (2620:10d:c021:18::175) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Thu, 28 Mar 2019 18:02:22 -0700 Received: by dev082.prn2.facebook.com (Postfix, from userid 572249) id 087FE37028DC; Thu, 28 Mar 2019 18:02:20 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrey Ignatov Smtp-Origin-Hostname: dev082.prn2.facebook.com To: CC: Andrey Ignatov , , , Smtp-Origin-Cluster: prn2c23 Subject: [PATCH bpf-next 2/2] selftests/bpf: Test variable offset stack access Date: Thu, 28 Mar 2019 18:01:58 -0700 Message-ID: <95a04a5fa33f856fef2df09518e43c1f25bb23e5.1553821057.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=2019-03-29_01:, , 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 Test different scenarios of indirect variable-offset stack access: out of bound access (>0), min_off below initialized part of the stack, max_off+size above initialized part of the stack, initialized stack. Example of output: ... #856/p indirect variable-offset stack access, out of bound OK #857/p indirect variable-offset stack access, max_off+size > max_initialized OK #858/p indirect variable-offset stack access, min_off < min_initialized OK #859/p indirect variable-offset stack access, ok OK ... Signed-off-by: Andrey Ignatov --- .../testing/selftests/bpf/verifier/var_off.c | 79 ++++++++++++++++++- 1 file changed, 77 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/verifier/var_off.c b/tools/testing/selftests/bpf/verifier/var_off.c index 1e536ff121a5..c4ebd0bb0781 100644 --- a/tools/testing/selftests/bpf/verifier/var_off.c +++ b/tools/testing/selftests/bpf/verifier/var_off.c @@ -40,7 +40,7 @@ .prog_type = BPF_PROG_TYPE_LWT_IN, }, { - "indirect variable-offset stack access", + "indirect variable-offset stack access, out of bound", .insns = { /* Fill the top 8 bytes of the stack */ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), @@ -60,7 +60,82 @@ BPF_EXIT_INSN(), }, .fixup_map_hash_8b = { 5 }, - .errstr = "variable stack read R2", + .errstr = "invalid stack type R2 var_off", .result = REJECT, .prog_type = BPF_PROG_TYPE_LWT_IN, }, +{ + "indirect variable-offset stack access, max_off+size > max_initialized", + .insns = { + /* Fill only the second from top 8 bytes of the stack. */ + BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0), + /* Get an unknown value. */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0), + /* Make it small and 4-byte aligned. */ + BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4), + BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16), + /* Add it to fp. We now have either fp-12 or fp-16, but we don't know + * which. fp-12 size 8 is partially uninitialized stack. + */ + BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10), + /* Dereference it indirectly. */ + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .fixup_map_hash_8b = { 5 }, + .errstr = "invalid indirect read from stack var_off", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_LWT_IN, +}, +{ + "indirect variable-offset stack access, min_off < min_initialized", + .insns = { + /* Fill only the top 8 bytes of the stack. */ + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), + /* Get an unknown value */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0), + /* Make it small and 4-byte aligned. */ + BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4), + BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16), + /* Add it to fp. We now have either fp-12 or fp-16, but we don't know + * which. fp-16 size 8 is partially uninitialized stack. + */ + BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10), + /* Dereference it indirectly. */ + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .fixup_map_hash_8b = { 5 }, + .errstr = "invalid indirect read from stack var_off", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_LWT_IN, +}, +{ + "indirect variable-offset stack access, ok", + .insns = { + /* Fill the top 16 bytes of the stack. */ + BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), + /* Get an unknown value. */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0), + /* Make it small and 4-byte aligned. */ + BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4), + BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16), + /* Add it to fp. We now have either fp-12 or fp-16, we don't know + * which, but either way it points to initialized stack. + */ + BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10), + /* Dereference it indirectly. */ + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .fixup_map_hash_8b = { 6 }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_LWT_IN, +},