From patchwork Fri Mar 21 16:45:04 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Blaise Boscaccy X-Patchwork-Id: 14025781 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2F6901E98EB; Fri, 21 Mar 2025 16:46:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742575581; cv=none; b=oIm8vQS/p0Rg9A2iZc4lA8+GlbpgsFzhqRXtpiZduf8oljrjq7w9GGUtwtvgDh3Xt5LNRM0lKjx8K7JCPgK97eCCV9QvfHPS8u16KByuoHbaqOkG0TlLHgDbL5nvPGNyHlENQY8ZtaMxJkY8tByhhR8htNUUC8Z4NTgAHma/JBc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742575581; c=relaxed/simple; bh=GWDmgEs4SVF4GEH2MK+44o35QcdVkWwcjYjnj1J0Zo0=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OMGZjuG5dfInUarvdG49Rxtw4a3Lcwd//ZIFFrquGCeooNCn3diiBhc9aSc7P8jWqhBBF1InzPReHVkhNSXSllHcs/bZqWwL5uDmC0f/KsWkRwYTorwc9/DREVbsX8w3u+qLLtMTTac97rcxaoDkS1mkKyRT6bAR8MjFCJKdUzc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=GtOBRgl4; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="GtOBRgl4" Received: from narnia.corp.microsoft.com (unknown [167.220.2.28]) by linux.microsoft.com (Postfix) with ESMTPSA id 193102025386; Fri, 21 Mar 2025 09:46:08 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 193102025386 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1742575577; bh=UzEqDSTXBuOj4+4tDZp8lLw090SqC2DfZSOyZh3D3T8=; h=From:To:Subject:Date:In-Reply-To:References:From; b=GtOBRgl4uOFpmkLR6dmrlBFQTb1NCiO32g/XxntTl2iU/HrTPMsxlYHhavHMwFw3V t3NAq8OQAwn1jXZ/iLAWhpCBj9IjqbvqdtIulYaOFhafg4+p3xofTOhjtGdcdfz36V D4TTUR05ns3kBp+nETrTz+2Zo7RgoEuzMppVELC0= From: Blaise Boscaccy To: Jonathan Corbet , David Howells , Herbert Xu , "David S. Miller" , Paul Moore , James Morris , "Serge E. Hallyn" , Masahiro Yamada , Nathan Chancellor , Nicolas Schier , Shuah Khan , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , =?utf-8?q?G=C3=BCnt?= =?utf-8?q?her_Noack?= , Nick Desaulniers , Bill Wendling , Justin Stitt , Blaise Boscaccy , Jarkko Sakkinen , Jan Stancek , Neal Gompa , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev, nkapron@google.com, teknoraver@meta.com, roberto.sassu@huawei.com, xiyou.wangcong@gmail.com Subject: [RFC PATCH security-next 2/4] hornet: Introduce sign-ebpf Date: Fri, 21 Mar 2025 09:45:04 -0700 Message-ID: <20250321164537.16719-3-bboscaccy@linux.microsoft.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250321164537.16719-1-bboscaccy@linux.microsoft.com> References: <20250321164537.16719-1-bboscaccy@linux.microsoft.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-State: RFC This introduces the sign-ebpf tool. It is very similar to the existing sign-file script, with one key difference, it will sign a file with with a signature computed off of arbitrary input data. This can used to sign an ebpf light skeleton loader program for verification via hornet. Typical usage is to provide a payload containing the lskel ebpf syscall program binary and it's associated maps, which can be extracted from the auto-generated skel header. Signed-off-by: Blaise Boscaccy --- scripts/Makefile | 1 + scripts/hornet/Makefile | 5 + scripts/hornet/sign-ebpf.c | 420 +++++++++++++++++++++++++++++++++++++ 3 files changed, 426 insertions(+) create mode 100644 scripts/hornet/Makefile create mode 100644 scripts/hornet/sign-ebpf.c diff --git a/scripts/Makefile b/scripts/Makefile index 46f860529df5e..a2cace05d7342 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -57,6 +57,7 @@ subdir-$(CONFIG_GENKSYMS) += genksyms subdir-$(CONFIG_GENDWARFKSYMS) += gendwarfksyms subdir-$(CONFIG_SECURITY_SELINUX) += selinux subdir-$(CONFIG_SECURITY_IPE) += ipe +subdir-$(CONFIG_SECURITY_HORNET) += hornet # Let clean descend into subdirs subdir- += basic dtc gdb kconfig mod diff --git a/scripts/hornet/Makefile b/scripts/hornet/Makefile new file mode 100644 index 0000000000000..ab71dbb8688e4 --- /dev/null +++ b/scripts/hornet/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +hostprogs-always-y := sign-ebpf + +HOSTCFLAGS_sign-ebpf.o = $(shell $(HOSTPKG_CONFIG) --cflags libcrypto 2> /dev/null) +HOSTLDLIBS_sign-ebpf = $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null || echo -lcrypto) diff --git a/scripts/hornet/sign-ebpf.c b/scripts/hornet/sign-ebpf.c new file mode 100644 index 0000000000000..ff98fddb79a15 --- /dev/null +++ b/scripts/hornet/sign-ebpf.c @@ -0,0 +1,420 @@ +/* Sign ebpf programs and skeletons using the given key. + * + * This program is heavily based on the kernel's sign-file tool + * with some minor additions to support the signing of eBPF lskels. + * + * Copyright © 2014-2016 Red Hat, Inc. All Rights Reserved. + * Copyright © 2015 Intel Corporation. + * Copyright © 2016 Hewlett Packard Enterprise Development LP + * Copyright © 2025 Microsoft Corporation. + * + * Authors: David Howells + * David Woodhouse + * Juerg Haefliger + * Blaise Boscaccy + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either version 2.1 + * of the licence, or (at your option) any later version. + */ +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#if OPENSSL_VERSION_MAJOR >= 3 +# define USE_PKCS11_PROVIDER +# include +# include +#else +# if !defined(OPENSSL_NO_ENGINE) && !defined(OPENSSL_NO_DEPRECATED_3_0) +# define USE_PKCS11_ENGINE +# include +# endif +#endif +#include "../ssl-common.h" + +/* + * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to + * assume that it's not available and its header file is missing and that we + * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts + * the options we have on specifying the X.509 certificate we want. + * + * Further, older versions of OpenSSL don't support manually adding signers to + * the PKCS#7 message so have to accept that we get a certificate included in + * the signature message. Nor do such older versions of OpenSSL support + * signing with anything other than SHA1 - so we're stuck with that if such is + * the case. + */ +#if defined(LIBRESSL_VERSION_NUMBER) || \ + OPENSSL_VERSION_NUMBER < 0x10000000L || \ + defined(OPENSSL_NO_CMS) +#define USE_PKCS7 +#endif +#ifndef USE_PKCS7 +#include +#else +#include +#endif + +struct module_signature { + uint8_t algo; /* Public-key crypto algorithm [0] */ + uint8_t hash; /* Digest algorithm [0] */ + uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ + uint8_t signer_len; /* Length of signer's name [0] */ + uint8_t key_id_len; /* Length of key identifier [0] */ + uint8_t __pad[3]; + uint32_t sig_len; /* Length of signature data */ +}; + +#define PKEY_ID_PKCS7 2 + +static char magic_number[] = "~eBPF signature appended~\n"; + +static __attribute__((noreturn)) +void format(void) +{ + fprintf(stderr, + "Usage: scripts/sign-ebpf [-dp] []\n"); + exit(2); +} + +static const char *key_pass; + +static int pem_pw_cb(char *buf, int len, int w, void *v) +{ + int pwlen; + + if (!key_pass) + return -1; + + pwlen = strlen(key_pass); + if (pwlen >= len) + return -1; + + strcpy(buf, key_pass); + + /* If it's wrong, don't keep trying it. */ + key_pass = NULL; + + return pwlen; +} + +static EVP_PKEY *read_private_key_pkcs11(const char *private_key_name) +{ + EVP_PKEY *private_key = NULL; +#ifdef USE_PKCS11_PROVIDER + OSSL_STORE_CTX *store; + + if (!OSSL_PROVIDER_try_load(NULL, "pkcs11", true)) + ERR(1, "OSSL_PROVIDER_try_load(pkcs11)"); + if (!OSSL_PROVIDER_try_load(NULL, "default", true)) + ERR(1, "OSSL_PROVIDER_try_load(default)"); + + store = OSSL_STORE_open(private_key_name, NULL, NULL, NULL, NULL); + ERR(!store, "OSSL_STORE_open"); + + while (!OSSL_STORE_eof(store)) { + OSSL_STORE_INFO *info = OSSL_STORE_load(store); + + if (!info) { + drain_openssl_errors(__LINE__, 0); + continue; + } + if (OSSL_STORE_INFO_get_type(info) == OSSL_STORE_INFO_PKEY) { + private_key = OSSL_STORE_INFO_get1_PKEY(info); + ERR(!private_key, "OSSL_STORE_INFO_get1_PKEY"); + } + OSSL_STORE_INFO_free(info); + if (private_key) + break; + } + OSSL_STORE_close(store); +#elif defined(USE_PKCS11_ENGINE) + ENGINE *e; + + ENGINE_load_builtin_engines(); + drain_openssl_errors(__LINE__, 1); + e = ENGINE_by_id("pkcs11"); + ERR(!e, "Load PKCS#11 ENGINE"); + if (ENGINE_init(e)) + drain_openssl_errors(__LINE__, 1); + else + ERR(1, "ENGINE_init"); + if (key_pass) + ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN"); + private_key = ENGINE_load_private_key(e, private_key_name, NULL, NULL); + ERR(!private_key, "%s", private_key_name); +#else + fprintf(stderr, "no pkcs11 engine/provider available\n"); + exit(1); +#endif + return private_key; +} + +static EVP_PKEY *read_private_key(const char *private_key_name) +{ + if (!strncmp(private_key_name, "pkcs11:", 7)) { + return read_private_key_pkcs11(private_key_name); + } else { + EVP_PKEY *private_key; + BIO *b; + + b = BIO_new_file(private_key_name, "rb"); + ERR(!b, "%s", private_key_name); + private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb, + NULL); + ERR(!private_key, "%s", private_key_name); + BIO_free(b); + + return private_key; + } +} + +static X509 *read_x509(const char *x509_name) +{ + unsigned char buf[2]; + X509 *x509; + BIO *b; + int n; + + b = BIO_new_file(x509_name, "rb"); + ERR(!b, "%s", x509_name); + + /* Look at the first two bytes of the file to determine the encoding */ + n = BIO_read(b, buf, 2); + if (n != 2) { + if (BIO_should_retry(b)) { + fprintf(stderr, "%s: Read wanted retry\n", x509_name); + exit(1); + } + if (n >= 0) { + fprintf(stderr, "%s: Short read\n", x509_name); + exit(1); + } + ERR(1, "%s", x509_name); + } + + ERR(BIO_reset(b) != 0, "%s", x509_name); + + if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84) + /* Assume raw DER encoded X.509 */ + x509 = d2i_X509_bio(b, NULL); + else + /* Assume PEM encoded X.509 */ + x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); + + BIO_free(b); + ERR(!x509, "%s", x509_name); + + return x509; +} + +int main(int argc, char **argv) +{ + struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; + char *hash_algo = NULL; + char *private_key_name = NULL, *raw_sig_name = NULL; + char *x509_name, *bin_name, *loader_name, *dest_name; + bool save_sig = false, replace_orig; + bool sign_only = false; + bool raw_sig = false; + unsigned char buf[4096]; + unsigned long loader_size, sig_size; + unsigned int use_signed_attrs; + const EVP_MD *digest_algo; + EVP_PKEY *private_key; +#ifndef USE_PKCS7 + CMS_ContentInfo *cms = NULL; + unsigned int use_keyid = 0; +#else + PKCS7 *pkcs7 = NULL; +#endif + X509 *x509; + BIO *bd, *bm, *bl; + int opt, n; + OpenSSL_add_all_algorithms(); + ERR_load_crypto_strings(); + ERR_clear_error(); + + key_pass = getenv("KBUILD_SIGN_PIN"); + +#ifndef USE_PKCS7 + use_signed_attrs = CMS_NOATTR; +#else + use_signed_attrs = PKCS7_NOATTR; +#endif + + do { + opt = getopt(argc, argv, "sdpk"); + switch (opt) { + case 's': raw_sig = true; break; + case 'p': save_sig = true; break; + case 'd': sign_only = true; save_sig = true; break; +#ifndef USE_PKCS7 + case 'k': use_keyid = CMS_USE_KEYID; break; +#endif + case -1: break; + default: format(); + } + } while (opt != -1); + + argc -= optind; + argv += optind; + if (argc < 5 || argc > 6) + format(); + + if (raw_sig) { + raw_sig_name = argv[0]; + hash_algo = argv[1]; + } else { + hash_algo = argv[0]; + private_key_name = argv[1]; + } + x509_name = argv[2]; + bin_name = argv[3]; + loader_name = argv[4]; + if (argc == 6 && strcmp(argv[4], argv[5]) != 0) { + dest_name = argv[5]; + replace_orig = false; + } else { + ERR(asprintf(&dest_name, "%s.~signed~", loader_name) < 0, + "asprintf"); + replace_orig = true; + } + +#ifdef USE_PKCS7 + if (strcmp(hash_algo, "sha1") != 0) { + fprintf(stderr, "sign-file: %s only supports SHA1 signing\n", + OPENSSL_VERSION_TEXT); + exit(3); + } +#endif + + /* Open the bin file */ + bm = BIO_new_file(bin_name, "rb"); + ERR(!bm, "%s", bin_name); + + if (!raw_sig) { + /* Read the private key and the X.509 cert the PKCS#7 message + * will point to. + */ + private_key = read_private_key(private_key_name); + x509 = read_x509(x509_name); + + /* Digest the module data. */ + OpenSSL_add_all_digests(); + drain_openssl_errors(__LINE__, 0); + digest_algo = EVP_get_digestbyname(hash_algo); + ERR(!digest_algo, "EVP_get_digestbyname"); + +#ifndef USE_PKCS7 + /* Load the signature message from the digest buffer. */ + cms = CMS_sign(NULL, NULL, NULL, NULL, + CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | + CMS_DETACHED | CMS_STREAM); + ERR(!cms, "CMS_sign"); + + ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, + CMS_NOCERTS | CMS_BINARY | + CMS_NOSMIMECAP | use_keyid | + use_signed_attrs), + "CMS_add1_signer"); + ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1, + "CMS_final"); + +#else + pkcs7 = PKCS7_sign(x509, private_key, NULL, bm, + PKCS7_NOCERTS | PKCS7_BINARY | + PKCS7_DETACHED | use_signed_attrs); + ERR(!pkcs7, "PKCS7_sign"); +#endif + + if (save_sig) { + char *sig_file_name; + BIO *b; + + ERR(asprintf(&sig_file_name, "%s.p7s", bin_name) < 0, + "asprintf"); + b = BIO_new_file(sig_file_name, "wb"); + ERR(!b, "%s", sig_file_name); +#ifndef USE_PKCS7 + ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) != 1, + "%s", sig_file_name); +#else + ERR(i2d_PKCS7_bio(b, pkcs7) != 1, + "%s", sig_file_name); +#endif + BIO_free(b); + } + + if (sign_only) { + BIO_free(bm); + return 0; + } + } + + /* Open the destination file now so that we can shovel the loader data + * across as we read it. + */ + bd = BIO_new_file(dest_name, "wb"); + ERR(!bd, "%s", dest_name); + + bl = BIO_new_file(loader_name, "rb"); + ERR(!bl, "%s", loader_name); + + + /* Append the marker and the PKCS#7 message to the destination file */ + ERR(BIO_reset(bm) < 0, "%s", bin_name); + ERR(BIO_reset(bl) < 0, "%s", loader_name); + while ((n = BIO_read(bl, buf, sizeof(buf))), + n > 0) { + ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); + } + BIO_free(bl); + BIO_free(bm); + ERR(n < 0, "%s", loader_name); + loader_size = BIO_number_written(bd); + + if (!raw_sig) { +#ifndef USE_PKCS7 + ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) != 1, "%s", dest_name); +#else + ERR(i2d_PKCS7_bio(bd, pkcs7) != 1, "%s", dest_name); +#endif + } else { + BIO *b; + + /* Read the raw signature file and write the data to the + * destination file + */ + b = BIO_new_file(raw_sig_name, "rb"); + ERR(!b, "%s", raw_sig_name); + while ((n = BIO_read(b, buf, sizeof(buf))), n > 0) + ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); + BIO_free(b); + } + + sig_size = BIO_number_written(bd) - loader_size; + sig_info.sig_len = htonl(sig_size); + ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); + ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); + + ERR(BIO_free(bd) != 1, "%s", dest_name); + + /* Finally, if we're signing in place, replace the original. */ + if (replace_orig) + ERR(rename(dest_name, loader_name) < 0, "%s", dest_name); + + return 0; +}