From patchwork Tue Aug 23 15:00:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12952384 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 221AAC32772 for ; Tue, 23 Aug 2022 17:26:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231603AbiHWR0h (ORCPT ); Tue, 23 Aug 2022 13:26:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235791AbiHWRZu (ORCPT ); Tue, 23 Aug 2022 13:25:50 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B8E77B7AB; Tue, 23 Aug 2022 08:03:36 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.229]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4MBspH4MnPz9v7P7; Tue, 23 Aug 2022 22:59:51 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwBnIhqd6wRjjU5GAA--.52413S12; Tue, 23 Aug 2022 16:03:06 +0100 (CET) From: Roberto Sassu To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, corbet@lwn.net, dhowells@redhat.com, jarkko@kernel.org, rostedt@goodmis.org, mingo@redhat.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, shuah@kernel.org Cc: bpf@vger.kernel.org, linux-doc@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, deso@posteo.net, Roberto Sassu Subject: [PATCH v13 10/10] selftests/bpf: Add test for bpf_verify_pkcs7_signature() kfunc Date: Tue, 23 Aug 2022 17:00:35 +0200 Message-Id: <20220823150035.711534-11-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220823150035.711534-1-roberto.sassu@huaweicloud.com> References: <20220823150035.711534-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: GxC2BwBnIhqd6wRjjU5GAA--.52413S12 X-Coremail-Antispam: 1UD129KBjvAXoWftw43ur43Cw47Jr15Wry8Krg_yoW8uw47Go Z3Gw43X3WrGr1UCr18KFykCryfWw48Ka4kAwnYv3srXFyDK3sIkr48Cw4fX342v39YqFyr uFn3Z3s7uFZ7trn5n29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUYK7kC6x804xWl14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK 8VAvwI8IcIk0rVWUWVWUuwAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF 0E3s1l82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vE j48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxV AFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26r4j6F4UM28EF7xvwVC2z280aVCY1x02 67AKxVW8Jr0_Cr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F4 0Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC 6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82 IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC2 0s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMI IF0xvE2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4UJVWxJr1l IxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4 A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjxUFgAwUUUUU X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQANBF1jj4I6UQAAsQ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Roberto Sassu Perform several tests to ensure the correct implementation of the bpf_verify_pkcs7_signature() kfunc. Do the tests with data signed with a generated testing key (by using sign-file from scripts/) and with the tcp_bic.ko kernel module if it is found in the system. The test does not fail if tcp_bic.ko is not found. First, perform an unsuccessful signature verification without data. Second, perform a successful signature verification with the session keyring and a new one created for testing. Then, ensure that permission and validation checks are done properly on the keyring provided to bpf_verify_pkcs7_signature(), despite those checks were deferred at the time the keyring was retrieved with bpf_lookup_user_key(). The tests expect to encounter an error if the Search permission is removed from the keyring, or the keyring is expired. Finally, perform a successful and unsuccessful signature verification with the keyrings with pre-determined IDs (the last test fails because the key is not in the platform keyring). The test is currently blacklisted for s390x (JIT does not support calling kernel function). Signed-off-by: Roberto Sassu --- tools/testing/selftests/bpf/DENYLIST.s390x | 1 + tools/testing/selftests/bpf/Makefile | 14 +- tools/testing/selftests/bpf/config | 5 + tools/testing/selftests/bpf/config.x86_64 | 5 - .../bpf/prog_tests/verify_pkcs7_sig.c | 399 ++++++++++++++++++ .../bpf/progs/test_verify_pkcs7_sig.c | 100 +++++ .../testing/selftests/bpf/verify_sig_setup.sh | 104 +++++ 7 files changed, 620 insertions(+), 8 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/verify_pkcs7_sig.c create mode 100644 tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c create mode 100755 tools/testing/selftests/bpf/verify_sig_setup.sh diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 585ed5d43da8..5adcbeb54eef 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -67,3 +67,4 @@ xdp_synproxy # JIT does not support calling kernel f unpriv_bpf_disabled # fentry setget_sockopt # attach unexpected error: -524 (trampoline) lookup_key # JIT does not support calling kernel function (kfunc) +verify_pkcs7_sig # JIT does not support calling kernel function (kfunc) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 8d59ec7f4c2d..5ae079e276b3 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -14,6 +14,7 @@ BPFTOOLDIR := $(TOOLSDIR)/bpf/bpftool APIDIR := $(TOOLSINCDIR)/uapi GENDIR := $(abspath ../../../../include/generated) GENHDR := $(GENDIR)/autoconf.h +HOSTPKG_CONFIG := pkg-config ifneq ($(wildcard $(GENHDR)),) GENFLAGS := -DHAVE_GENHDR @@ -75,7 +76,7 @@ TEST_PROGS := test_kmod.sh \ test_xsk.sh TEST_PROGS_EXTENDED := with_addr.sh \ - with_tunnels.sh ima_setup.sh \ + with_tunnels.sh ima_setup.sh verify_sig_setup.sh \ test_xdp_vlan.sh test_bpftool.py # Compile but not part of 'make run_tests' @@ -84,7 +85,7 @@ TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \ test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \ xskxceiver xdp_redirect_multi xdp_synproxy -TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read +TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read $(OUTPUT)/sign-file # Emit succinct information message describing current building step # $1 - generic step name (e.g., CC, LINK, etc); @@ -189,6 +190,12 @@ $(OUTPUT)/urandom_read: urandom_read.c urandom_read_aux.c $(OUTPUT)/liburandom_r -fuse-ld=$(LLD) -Wl,-znoseparate-code \ -Wl,-rpath=. -Wl,--build-id=sha1 -o $@ +$(OUTPUT)/sign-file: ../../../../scripts/sign-file.c + $(call msg,SIGN-FILE,,$@) + $(Q)$(CC) $(shell $(HOSTPKG_CONFIG)--cflags libcrypto 2> /dev/null) \ + $< -o $@ \ + $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null || echo -lcrypto) + $(OUTPUT)/bpf_testmod.ko: $(VMLINUX_BTF) $(wildcard bpf_testmod/Makefile bpf_testmod/*.[ch]) $(call msg,MOD,,$@) $(Q)$(RM) bpf_testmod/bpf_testmod.ko # force re-compilation @@ -514,7 +521,8 @@ TRUNNER_EXTRA_SOURCES := test_progs.c cgroup_helpers.c trace_helpers.c \ TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read $(OUTPUT)/bpf_testmod.ko \ $(OUTPUT)/liburandom_read.so \ $(OUTPUT)/xdp_synproxy \ - ima_setup.sh \ + $(OUTPUT)/sign-file \ + ima_setup.sh verify_sig_setup.sh \ $(wildcard progs/btf_dump_test_case_*.c) TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS) -DENABLE_ATOMICS_TESTS diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index add5a5a919b4..905a9be8d0a2 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -33,6 +33,11 @@ CONFIG_IPV6_TUNNEL=y CONFIG_KEYS=y CONFIG_LIRC=y CONFIG_LWTUNNEL=y +CONFIG_MODULE_SIG=y +CONFIG_MODULE_SRCVERSION_ALL=y +CONFIG_MODULE_UNLOAD=y +CONFIG_MODULES=y +CONFIG_MODVERSIONS=y CONFIG_MPLS=y CONFIG_MPLS_IPTUNNEL=y CONFIG_MPLS_ROUTING=y diff --git a/tools/testing/selftests/bpf/config.x86_64 b/tools/testing/selftests/bpf/config.x86_64 index ce70c9509204..21ce5ea4304e 100644 --- a/tools/testing/selftests/bpf/config.x86_64 +++ b/tools/testing/selftests/bpf/config.x86_64 @@ -145,11 +145,6 @@ CONFIG_MCORE2=y CONFIG_MEMCG=y CONFIG_MEMORY_FAILURE=y CONFIG_MINIX_SUBPARTITION=y -CONFIG_MODULE_SIG=y -CONFIG_MODULE_SRCVERSION_ALL=y -CONFIG_MODULE_UNLOAD=y -CONFIG_MODULES=y -CONFIG_MODVERSIONS=y CONFIG_NAMESPACES=y CONFIG_NET=y CONFIG_NET_9P=y diff --git a/tools/testing/selftests/bpf/prog_tests/verify_pkcs7_sig.c b/tools/testing/selftests/bpf/prog_tests/verify_pkcs7_sig.c new file mode 100644 index 000000000000..20be68d4cce4 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/verify_pkcs7_sig.c @@ -0,0 +1,399 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "test_verify_pkcs7_sig.skel.h" + +#define MAX_DATA_SIZE (1024 * 1024) +#define MAX_SIG_SIZE 1024 + +#define VERIFY_USE_SECONDARY_KEYRING (1UL) +#define VERIFY_USE_PLATFORM_KEYRING (2UL) + +/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */ +#define MODULE_SIG_STRING "~Module signature appended~\n" + +/* + * Module signature information block. + * + * The constituents of the signature section are, in order: + * + * - Signer's name + * - Key identifier + * - Signature data + * - Information block + */ +struct module_signature { + u8 algo; /* Public-key crypto algorithm [0] */ + u8 hash; /* Digest algorithm [0] */ + u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */ + u8 signer_len; /* Length of signer's name [0] */ + u8 key_id_len; /* Length of key identifier [0] */ + u8 __pad[3]; + __be32 sig_len; /* Length of signature data */ +}; + +struct data { + u8 data[MAX_DATA_SIZE]; + u32 data_len; + u8 sig[MAX_SIG_SIZE]; + u32 sig_len; +}; + +static bool kfunc_not_supported; + +static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt, + va_list args) +{ + if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found in kernel or module BTFs\n")) + return 0; + + if (strcmp(va_arg(args, char *), "bpf_verify_pkcs7_signature")) + return 0; + + kfunc_not_supported = true; + return 0; +} + +static int _run_setup_process(const char *setup_dir, const char *cmd) +{ + int child_pid, child_status; + + child_pid = fork(); + if (child_pid == 0) { + execlp("./verify_sig_setup.sh", "./verify_sig_setup.sh", cmd, + setup_dir, NULL); + exit(errno); + + } else if (child_pid > 0) { + waitpid(child_pid, &child_status, 0); + return WEXITSTATUS(child_status); + } + + return -EINVAL; +} + +static int populate_data_item_str(const char *tmp_dir, struct data *data_item) +{ + struct stat st; + char data_template[] = "/tmp/dataXXXXXX"; + char path[PATH_MAX]; + int ret, fd, child_status, child_pid; + + data_item->data_len = 4; + memcpy(data_item->data, "test", data_item->data_len); + + fd = mkstemp(data_template); + if (fd == -1) + return -errno; + + ret = write(fd, data_item->data, data_item->data_len); + + close(fd); + + if (ret != data_item->data_len) { + ret = -EIO; + goto out; + } + + child_pid = fork(); + + if (child_pid == -1) { + ret = -errno; + goto out; + } + + if (child_pid == 0) { + snprintf(path, sizeof(path), "%s/signing_key.pem", tmp_dir); + + return execlp("./sign-file", "./sign-file", "-d", "sha256", + path, path, data_template, NULL); + } + + waitpid(child_pid, &child_status, 0); + + ret = WEXITSTATUS(child_status); + if (ret) + goto out; + + snprintf(path, sizeof(path), "%s.p7s", data_template); + + ret = stat(path, &st); + if (ret == -1) { + ret = -errno; + goto out; + } + + if (st.st_size > sizeof(data_item->sig)) { + ret = -EINVAL; + goto out_sig; + } + + data_item->sig_len = st.st_size; + + fd = open(path, O_RDONLY); + if (fd == -1) { + ret = -errno; + goto out_sig; + } + + ret = read(fd, data_item->sig, data_item->sig_len); + + close(fd); + + if (ret != data_item->sig_len) { + ret = -EIO; + goto out_sig; + } + + ret = 0; +out_sig: + unlink(path); +out: + unlink(data_template); + return ret; +} + +static int populate_data_item_mod(struct data *data_item) +{ + char mod_path[PATH_MAX], *mod_path_ptr; + struct stat st; + void *mod; + FILE *fp; + struct module_signature ms; + int ret, fd, modlen, marker_len, sig_len; + + data_item->data_len = 0; + + if (stat("/lib/modules", &st) == -1) + return 0; + + /* Requires CONFIG_TCP_CONG_BIC=m. */ + fp = popen("find /lib/modules/$(uname -r) -name tcp_bic.ko", "r"); + if (!fp) + return 0; + + mod_path_ptr = fgets(mod_path, sizeof(mod_path), fp); + pclose(fp); + + if (!mod_path_ptr) + return 0; + + mod_path_ptr = strchr(mod_path, '\n'); + if (!mod_path_ptr) + return 0; + + *mod_path_ptr = '\0'; + + if (stat(mod_path, &st) == -1) + return 0; + + modlen = st.st_size; + marker_len = sizeof(MODULE_SIG_STRING) - 1; + + fd = open(mod_path, O_RDONLY); + if (fd == -1) + return -errno; + + mod = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + + close(fd); + + if (mod == MAP_FAILED) + return -errno; + + if (strncmp(mod + modlen - marker_len, MODULE_SIG_STRING, marker_len)) { + ret = -EINVAL; + goto out; + } + + modlen -= marker_len; + + memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms)); + + sig_len = __be32_to_cpu(ms.sig_len); + modlen -= sig_len + sizeof(ms); + + if (modlen > sizeof(data_item->data)) { + ret = -E2BIG; + goto out; + } + + memcpy(data_item->data, mod, modlen); + data_item->data_len = modlen; + + if (sig_len > sizeof(data_item->sig)) { + ret = -E2BIG; + goto out; + } + + memcpy(data_item->sig, mod + modlen, sig_len); + data_item->sig_len = sig_len; + ret = 0; +out: + munmap(mod, st.st_size); + return ret; +} + +void test_verify_pkcs7_sig(void) +{ + libbpf_print_fn_t old_print_cb; + char tmp_dir_template[] = "/tmp/verify_sigXXXXXX"; + char *tmp_dir; + struct test_verify_pkcs7_sig *skel = NULL; + struct bpf_map *map; + struct data data; + int ret, zero = 0; + + /* Trigger creation of session keyring. */ + syscall(__NR_request_key, "keyring", "_uid.0", NULL, + KEY_SPEC_SESSION_KEYRING); + + tmp_dir = mkdtemp(tmp_dir_template); + if (!ASSERT_OK_PTR(tmp_dir, "mkdtemp")) + return; + + ret = _run_setup_process(tmp_dir, "setup"); + if (!ASSERT_OK(ret, "_run_setup_process")) + goto close_prog; + + skel = test_verify_pkcs7_sig__open(); + if (!ASSERT_OK_PTR(skel, "test_verify_pkcs7_sig__open")) + goto close_prog; + + old_print_cb = libbpf_set_print(libbpf_print_cb); + ret = test_verify_pkcs7_sig__load(skel); + libbpf_set_print(old_print_cb); + + if (ret < 0 && kfunc_not_supported) { + printf( + "%s:SKIP:bpf_verify_pkcs7_signature() kfunc not supported\n", + __func__); + test__skip(); + goto close_prog; + } + + if (!ASSERT_OK(ret, "test_verify_pkcs7_sig__load")) + goto close_prog; + + ret = test_verify_pkcs7_sig__attach(skel); + if (!ASSERT_OK(ret, "test_verify_pkcs7_sig__attach")) + goto close_prog; + + map = bpf_object__find_map_by_name(skel->obj, "data_input"); + if (!ASSERT_OK_PTR(map, "data_input not found")) + goto close_prog; + + skel->bss->monitored_pid = getpid(); + + /* Test without data and signature. */ + skel->bss->user_keyring_serial = KEY_SPEC_SESSION_KEYRING; + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, BPF_ANY); + if (!ASSERT_LT(ret, 0, "bpf_map_update_elem data_input")) + goto close_prog; + + /* Test successful signature verification with session keyring. */ + ret = populate_data_item_str(tmp_dir, &data); + if (!ASSERT_OK(ret, "populate_data_item_str")) + goto close_prog; + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, BPF_ANY); + if (!ASSERT_OK(ret, "bpf_map_update_elem data_input")) + goto close_prog; + + /* Test successful signature verification with testing keyring. */ + skel->bss->user_keyring_serial = syscall(__NR_request_key, "keyring", + "ebpf_testing_keyring", NULL, + KEY_SPEC_SESSION_KEYRING); + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, BPF_ANY); + if (!ASSERT_OK(ret, "bpf_map_update_elem data_input")) + goto close_prog; + + /* + * Ensure key_task_permission() is called and rejects the keyring + * (no Search permission). + */ + syscall(__NR_keyctl, KEYCTL_SETPERM, skel->bss->user_keyring_serial, + 0x37373737); + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, BPF_ANY); + if (!ASSERT_LT(ret, 0, "bpf_map_update_elem data_input")) + goto close_prog; + + syscall(__NR_keyctl, KEYCTL_SETPERM, skel->bss->user_keyring_serial, + 0x3f3f3f3f); + + /* + * Ensure key_validate() is called and rejects the keyring (key expired) + */ + syscall(__NR_keyctl, KEYCTL_SET_TIMEOUT, + skel->bss->user_keyring_serial, 1); + sleep(1); + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, BPF_ANY); + if (!ASSERT_LT(ret, 0, "bpf_map_update_elem data_input")) + goto close_prog; + + skel->bss->user_keyring_serial = KEY_SPEC_SESSION_KEYRING; + + /* Test with corrupted data (signature verification should fail). */ + data.data[0] = 'a'; + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, BPF_ANY); + if (!ASSERT_LT(ret, 0, "bpf_map_update_elem data_input")) + goto close_prog; + + ret = populate_data_item_mod(&data); + if (!ASSERT_OK(ret, "populate_data_item_mod")) + goto close_prog; + + /* Test signature verification with system keyrings. */ + if (data.data_len) { + skel->bss->user_keyring_serial = 0; + skel->bss->system_keyring_id = 0; + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, + BPF_ANY); + if (!ASSERT_OK(ret, "bpf_map_update_elem data_input")) + goto close_prog; + + skel->bss->system_keyring_id = VERIFY_USE_SECONDARY_KEYRING; + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, + BPF_ANY); + if (!ASSERT_OK(ret, "bpf_map_update_elem data_input")) + goto close_prog; + + skel->bss->system_keyring_id = VERIFY_USE_PLATFORM_KEYRING; + + ret = bpf_map_update_elem(bpf_map__fd(map), &zero, &data, + BPF_ANY); + ASSERT_LT(ret, 0, "bpf_map_update_elem data_input"); + } + +close_prog: + _run_setup_process(tmp_dir, "cleanup"); + + if (!skel) + return; + + skel->bss->monitored_pid = 0; + test_verify_pkcs7_sig__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c b/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c new file mode 100644 index 000000000000..4ceab545d99a --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_verify_pkcs7_sig.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + */ + +#include "vmlinux.h" +#include +#include +#include + +#define MAX_DATA_SIZE (1024 * 1024) +#define MAX_SIG_SIZE 1024 + +typedef __u8 u8; +typedef __u16 u16; +typedef __u32 u32; +typedef __u64 u64; + +struct bpf_dynptr { + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + +extern struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; +extern struct bpf_key *bpf_lookup_system_key(__u64 id) __ksym; +extern void bpf_key_put(struct bpf_key *key) __ksym; +extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr, + struct bpf_dynptr *sig_ptr, + struct bpf_key *trusted_keyring) __ksym; + +u32 monitored_pid; +u32 user_keyring_serial; +u64 system_keyring_id; + +struct data { + u8 data[MAX_DATA_SIZE]; + u32 data_len; + u8 sig[MAX_SIG_SIZE]; + u32 sig_len; +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, struct data); +} data_input SEC(".maps"); + +char _license[] SEC("license") = "GPL"; + +SEC("lsm.s/bpf") +int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size) +{ + struct bpf_dynptr data_ptr, sig_ptr; + struct data *data_val; + struct bpf_key *trusted_keyring; + u32 pid; + u64 value; + int ret, zero = 0; + + pid = bpf_get_current_pid_tgid() >> 32; + if (pid != monitored_pid) + return 0; + + data_val = bpf_map_lookup_elem(&data_input, &zero); + if (!data_val) + return 0; + + bpf_probe_read(&value, sizeof(value), &attr->value); + + bpf_copy_from_user(data_val, sizeof(struct data), + (void *)(unsigned long)value); + + if (data_val->data_len > sizeof(data_val->data)) + return -EINVAL; + + bpf_dynptr_from_mem(data_val->data, data_val->data_len, 0, &data_ptr); + + if (data_val->sig_len > sizeof(data_val->sig)) + return -EINVAL; + + bpf_dynptr_from_mem(data_val->sig, data_val->sig_len, 0, &sig_ptr); + + if (user_keyring_serial) + trusted_keyring = bpf_lookup_user_key(user_keyring_serial, 0); + else + trusted_keyring = bpf_lookup_system_key(system_keyring_id); + + if (!trusted_keyring) + return -ENOENT; + + ret = bpf_verify_pkcs7_signature(&data_ptr, &sig_ptr, trusted_keyring); + + bpf_key_put(trusted_keyring); + + return ret; +} diff --git a/tools/testing/selftests/bpf/verify_sig_setup.sh b/tools/testing/selftests/bpf/verify_sig_setup.sh new file mode 100755 index 000000000000..ba08922b4a27 --- /dev/null +++ b/tools/testing/selftests/bpf/verify_sig_setup.sh @@ -0,0 +1,104 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e +set -u +set -o pipefail + +VERBOSE="${SELFTESTS_VERBOSE:=0}" +LOG_FILE="$(mktemp /tmp/verify_sig_setup.log.XXXXXX)" + +x509_genkey_content="\ +[ req ] +default_bits = 2048 +distinguished_name = req_distinguished_name +prompt = no +string_mask = utf8only +x509_extensions = myexts + +[ req_distinguished_name ] +CN = eBPF Signature Verification Testing Key + +[ myexts ] +basicConstraints=critical,CA:FALSE +keyUsage=digitalSignature +subjectKeyIdentifier=hash +authorityKeyIdentifier=keyid +" + +usage() +{ + echo "Usage: $0 " + exit 1 +} + +setup() +{ + local tmp_dir="$1" + + echo "${x509_genkey_content}" > ${tmp_dir}/x509.genkey + + openssl req -new -nodes -utf8 -sha256 -days 36500 \ + -batch -x509 -config ${tmp_dir}/x509.genkey \ + -outform PEM -out ${tmp_dir}/signing_key.pem \ + -keyout ${tmp_dir}/signing_key.pem 2>&1 + + openssl x509 -in ${tmp_dir}/signing_key.pem -out \ + ${tmp_dir}/signing_key.der -outform der + + key_id=$(cat ${tmp_dir}/signing_key.der | keyctl padd asymmetric ebpf_testing_key @s) + + keyring_id=$(keyctl newring ebpf_testing_keyring @s) + keyctl link $key_id $keyring_id +} + +cleanup() { + local tmp_dir="$1" + + keyctl unlink $(keyctl search @s asymmetric ebpf_testing_key) @s + keyctl unlink $(keyctl search @s keyring ebpf_testing_keyring) @s + rm -rf ${tmp_dir} +} + +catch() +{ + local exit_code="$1" + local log_file="$2" + + if [[ "${exit_code}" -ne 0 ]]; then + cat "${log_file}" >&3 + fi + + rm -f "${log_file}" + exit ${exit_code} +} + +main() +{ + [[ $# -ne 2 ]] && usage + + local action="$1" + local tmp_dir="$2" + + [[ ! -d "${tmp_dir}" ]] && echo "Directory ${tmp_dir} doesn't exist" && exit 1 + + if [[ "${action}" == "setup" ]]; then + setup "${tmp_dir}" + elif [[ "${action}" == "cleanup" ]]; then + cleanup "${tmp_dir}" + else + echo "Unknown action: ${action}" + exit 1 + fi +} + +trap 'catch "$?" "${LOG_FILE}"' EXIT + +if [[ "${VERBOSE}" -eq 0 ]]; then + # Save the stderr to 3 so that we can output back to + # it incase of an error. + exec 3>&2 1>"${LOG_FILE}" 2>&1 +fi + +main "$@" +rm -f "${LOG_FILE}"