From patchwork Fri Dec 16 21:43:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Marchevsky X-Patchwork-Id: 13075465 X-Patchwork-Delegate: bpf@iogearbox.net 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 2B645C4332F for ; Fri, 16 Dec 2022 21:43:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229526AbiLPVnc (ORCPT ); Fri, 16 Dec 2022 16:43:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229471AbiLPVnc (ORCPT ); Fri, 16 Dec 2022 16:43:32 -0500 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E25932B9C for ; Fri, 16 Dec 2022 13:43:31 -0800 (PST) Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.17.1.19/8.17.1.19) with ESMTP id 2BGJx3Pq022876 for ; Fri, 16 Dec 2022 13:43:30 -0800 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-transfer-encoding : content-type; s=facebook; bh=UxpgzO1qFcybBG6a04570D4IOjY4BE8dRpwzVm5vqRk=; b=jD4LzZ5OhrmaJR83VLm/Sh/R/muuY5ufHUhVYoYGtqqG2gPpeQvxWuiW8M3+ZmPL67dj bWDHOjeDJgkr8+fm7wvdZERMcU8wtgufRrxMom6+AT25ETJdFjyAJBvP/65k48I77sBM mb8EeKp2La6ZIxPIGO89Xse6/C5akYFjUWA= Received: from mail.thefacebook.com ([163.114.132.120]) by m0089730.ppops.net (PPS) with ESMTPS id 3mgsfdawcr-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Dec 2022 13:43:30 -0800 Received: from twshared19053.17.frc2.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Fri, 16 Dec 2022 13:43:28 -0800 Received: by devbig077.ldc1.facebook.com (Postfix, from userid 158236) id 1107A12A1EDAC; Fri, 16 Dec 2022 13:43:22 -0800 (PST) From: Dave Marchevsky To: CC: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Kernel Team , Yonghong Song , Dave Marchevsky , Yonghong Song Subject: [PATCH v3 bpf-next 2/2] selftests/bpf: Add verifier test exercising jit PROBE_MEM logic Date: Fri, 16 Dec 2022 13:43:19 -0800 Message-ID: <20221216214319.3408356-2-davemarchevsky@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221216214319.3408356-1-davemarchevsky@fb.com> References: <20221216214319.3408356-1-davemarchevsky@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: 8DogRcHM3Bfys6W_jW73gbU5GUlXXvVS X-Proofpoint-ORIG-GUID: 8DogRcHM3Bfys6W_jW73gbU5GUlXXvVS X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-16_14,2022-12-15_02,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This patch adds a test exercising logic that was fixed / improved in the previous patch in the series, as well as general sanity checking for jit's PROBE_MEM logic which should've been unaffected by the previous patch. The added verifier test does the following: * Acquire a referenced kptr to struct prog_test_ref_kfunc using existing net/bpf/test_run.c kfunc * Helper returns ptr to a specific prog_test_ref_kfunc whose first two fields - both ints - have been prepopulated w/ vals 42 and 108, respectively * kptr_xchg the acquired ptr into an arraymap * Do a direct map_value load of the just-added ptr * Goal of all this setup is to get an unreferenced kptr pointing to struct with ints of known value, which is the result of this step * Using unreferenced kptr obtained in previous step, do loads of prog_test_ref_kfunc.a (offset 0) and .b (offset 4) * Then incr the kptr by 8 and load prog_test_ref_kfunc.a again (this time at offset -8) * Add all the loaded ints together and return Before the PROBE_MEM fixes in previous patch, the loads at offset 0 and 4 would succeed, while the load at offset -8 would incorrectly fail runtime check emitted by the JIT and 0 out dst reg as a result. This confirmed by retval of 150 for this test before previous patch - since second .a read is 0'd out - and a retval of 192 with the fixed logic. The test exercises the two optimizations to fixed logic added in last patch as well: * First load, with insn "r8 = *(u32 *)(r9 + 0)" exercises "insn->off is 0, no need to add / sub from src_reg" optimization * Third load, with insn "r9 = *(u32 *)(r9 - 8)" exercises "src_reg == dst_reg, no need to restore src_reg after load" optimization Signed-off-by: Dave Marchevsky Acked-by: Yonghong Song --- v2 -> v3: lore.kernel.org/bpf/20221216183122.2040142-2-davemarchevsky@fb.com * Remove unnecessary '\n's in asm statements (Yonghong) * Add Yonghong ack v1 -> v2: lore.kernel.org/bpf/20221213182726.325137-2-davemarchevsky@fb.com * Rewrite the test to be a "normal" C prog in selftests/bpf/progs. Result is a much easier-to-understand test with assembly used only for the 3 loads. (Yonghong) .../selftests/bpf/prog_tests/jit_probe_mem.c | 28 +++++++++ .../selftests/bpf/progs/jit_probe_mem.c | 61 +++++++++++++++++++ 2 files changed, 89 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/jit_probe_mem.c create mode 100644 tools/testing/selftests/bpf/progs/jit_probe_mem.c diff --git a/tools/testing/selftests/bpf/prog_tests/jit_probe_mem.c b/tools/testing/selftests/bpf/prog_tests/jit_probe_mem.c new file mode 100644 index 000000000000..5639428607e6 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/jit_probe_mem.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ +#include +#include + +#include "jit_probe_mem.skel.h" + +void test_jit_probe_mem(void) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .repeat = 1, + ); + struct jit_probe_mem *skel; + int ret; + + skel = jit_probe_mem__open_and_load(); + if (!ASSERT_OK_PTR(skel, "jit_probe_mem__open_and_load")) + return; + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_jit_probe_mem), &opts); + ASSERT_OK(ret, "jit_probe_mem ret"); + ASSERT_OK(opts.retval, "jit_probe_mem opts.retval"); + ASSERT_EQ(skel->data->total_sum, 192, "jit_probe_mem total_sum"); + + jit_probe_mem__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/jit_probe_mem.c b/tools/testing/selftests/bpf/progs/jit_probe_mem.c new file mode 100644 index 000000000000..1263053d1bd0 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/jit_probe_mem.c @@ -0,0 +1,61 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ +#include +#include +#include + +static struct prog_test_ref_kfunc __kptr_ref *v; +long total_sum = -1; + +extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym; +extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; + +SEC("tc") +int test_jit_probe_mem(struct __sk_buff *ctx) +{ + struct prog_test_ref_kfunc *p; + unsigned long zero = 0, sum; + + p = bpf_kfunc_call_test_acquire(&zero); + if (!p) + return 1; + + p = bpf_kptr_xchg(&v, p); + if (p) + goto release_out; + + /* Direct map value access of kptr, should be PTR_UNTRUSTED */ + p = v; + if (!p) + return 1; + + asm volatile ( + "r9 = %[p];" + "%[sum] = 0;" + + /* r8 = p->a */ + "r8 = *(u32 *)(r9 + 0);" + "%[sum] += r8;" + + /* r8 = p->b */ + "r8 = *(u32 *)(r9 + 4);" + "%[sum] += r8;" + + "r9 += 8;" + /* r9 = p->a */ + "r9 = *(u32 *)(r9 - 8);" + "%[sum] += r9;" + + : [sum] "=r"(sum) + : [p] "r"(p) + : "r8", "r9" + ); + + total_sum = sum; + return 0; +release_out: + bpf_kfunc_call_test_release(p); + return 1; +} + +char _license[] SEC("license") = "GPL";