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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42AB4CCA47F for ; Fri, 1 Jul 2022 12:47:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234791AbiGAMrr (ORCPT ); Fri, 1 Jul 2022 08:47:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236637AbiGAMrp (ORCPT ); Fri, 1 Jul 2022 08:47:45 -0400 Received: from www62.your-server.de (www62.your-server.de [213.133.104.62]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A29AD34643 for ; Fri, 1 Jul 2022 05:47:43 -0700 (PDT) Received: from 226.206.1.85.dynamic.wline.res.cust.swisscom.ch ([85.1.206.226] helo=localhost) by www62.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1o7G3i-00044R-1U; Fri, 01 Jul 2022 14:47:42 +0200 From: Daniel Borkmann To: ast@kernel.org Cc: andrii@kernel.org, john.fastabend@gmail.com, liulin063@gmail.com, bpf@vger.kernel.org, Daniel Borkmann Subject: [PATCH bpf 3/4] bpf, selftests: Add verifier test case for imm=0,umin=0,umax=1 scalar Date: Fri, 1 Jul 2022 14:47:26 +0200 Message-Id: <20220701124727.11153-3-daniel@iogearbox.net> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20220701124727.11153-1-daniel@iogearbox.net> References: <20220701124727.11153-1-daniel@iogearbox.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.103.6/26590/Fri Jul 1 09:25:21 2022) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add a test case to trigger the constant scalar issue which leaves the register in scalar(imm=0,umin=0,umax=1,var_off=(0x0; 0x0)) state. Make use of dead code elimination, so that we can see the verifier bailing out on unfixed kernels. For the condition, we use jle given it checks on umax bound. Before: # ./test_verifier 743 #743/p jump & dead code elimination FAIL Failed to load prog 'Permission denied'! R4 !read_ok verification time 11 usec stack depth 0 processed 13 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 Summary: 0 PASSED, 0 SKIPPED, 1 FAILED After: # ./test_verifier 743 #743/p jump & dead code elimination OK Summary: 1 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/verifier/jump.c | 22 +++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/testing/selftests/bpf/verifier/jump.c b/tools/testing/selftests/bpf/verifier/jump.c index 6f951d1ff0a4..497fe17d2eaf 100644 --- a/tools/testing/selftests/bpf/verifier/jump.c +++ b/tools/testing/selftests/bpf/verifier/jump.c @@ -373,3 +373,25 @@ .result = ACCEPT, .retval = 3, }, +{ + "jump & dead code elimination", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_ALU64_IMM(BPF_NEG, BPF_REG_3, 0), + BPF_ALU64_IMM(BPF_NEG, BPF_REG_3, 0), + BPF_ALU64_IMM(BPF_OR, BPF_REG_3, 32767), + BPF_JMP_IMM(BPF_JSGE, BPF_REG_3, 0, 1), + BPF_EXIT_INSN(), + BPF_JMP_IMM(BPF_JSLE, BPF_REG_3, 0x8000, 1), + BPF_EXIT_INSN(), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -32767), + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_JMP_IMM(BPF_JLE, BPF_REG_3, 0, 1), + BPF_MOV64_REG(BPF_REG_0, BPF_REG_4), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + .retval = 2, +}, -- 2.27.0