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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/*
* Copyright (C) 2025 Google LLC.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <getopt.h>
#include <err.h>
#include <openssl/opensslv.h>
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/cms.h>
#include <linux/keyctl.h>
#include <errno.h>
#include <bpf/skel_internal.h>
#include "main.h"
#define OPEN_SSL_ERR_BUF_LEN 256
static void display_openssl_errors(int l)
{
char buf[OPEN_SSL_ERR_BUF_LEN];
const char *file;
const char *data;
unsigned long e;
int flags;
int line;
while ((e = ERR_get_error_all(&file, &line, NULL, &data, &flags))) {
ERR_error_string_n(e, buf, sizeof(buf));
if (data && (flags & ERR_TXT_STRING)) {
p_err("OpenSSL %s: %s:%d: %s", buf, file, line, data);
} else {
p_err("OpenSSL %s: %s:%d", buf, file, line);
}
}
}
#define DISPLAY_OSSL_ERR(cond) \
do { \
bool __cond = (cond); \
if (__cond && ERR_peek_error()) \
display_openssl_errors(__LINE__);\
} while (0)
static EVP_PKEY *read_private_key(const char *pkey_path)
{
EVP_PKEY *private_key = NULL;
BIO *b;
b = BIO_new_file(pkey_path, "rb");
private_key = PEM_read_bio_PrivateKey(b, NULL, NULL, NULL);
BIO_free(b);
DISPLAY_OSSL_ERR(!private_key);
return private_key;
}
static X509 *read_x509(const char *x509_name)
{
unsigned char buf[2];
X509 *x509 = NULL;
BIO *b;
int n;
b = BIO_new_file(x509_name, "rb");
if (!b)
goto cleanup;
/* Look at the first two bytes of the file to determine the encoding */
n = BIO_read(b, buf, 2);
if (n != 2)
goto cleanup;
if (BIO_reset(b) != 0)
goto cleanup;
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);
cleanup:
BIO_free(b);
DISPLAY_OSSL_ERR(!x509);
return x509;
}
__u32 register_session_key(const char *key_der_path)
{
unsigned char *der_buf = NULL;
X509 *x509 = NULL;
int key_id = -1;
int der_len;
if (!key_der_path)
return key_id;
x509 = read_x509(key_der_path);
if (!x509)
goto cleanup;
der_len = i2d_X509(x509, &der_buf);
if (der_len < 0)
goto cleanup;
key_id = syscall(__NR_add_key, "asymmetric", key_der_path, der_buf,
(size_t)der_len, KEY_SPEC_SESSION_KEYRING);
cleanup:
X509_free(x509);
OPENSSL_free(der_buf);
DISPLAY_OSSL_ERR(key_id == -1);
return key_id;
}
int bpftool_prog_sign(struct bpf_load_and_run_opts *opts)
{
BIO *bd_in = NULL, *bd_out = NULL;
EVP_PKEY *private_key = NULL;
CMS_ContentInfo *cms = NULL;
long actual_sig_len = 0;
X509 *x509 = NULL;
int err = 0;
bd_in = BIO_new_mem_buf(opts->insns, opts->insns_sz);
if (!bd_in) {
err = -ENOMEM;
goto cleanup;
}
private_key = read_private_key(private_key_path);
if (!private_key) {
err = -EINVAL;
goto cleanup;
}
x509 = read_x509(cert_path);
if (!x509) {
err = -EINVAL;
goto cleanup;
}
cms = CMS_sign(NULL, NULL, NULL, NULL,
CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED |
CMS_STREAM);
if (!cms) {
err = -EINVAL;
goto cleanup;
}
if (!CMS_add1_signer(cms, x509, private_key, EVP_sha256(),
CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP |
CMS_USE_KEYID | CMS_NOATTR)) {
err = -EINVAL;
goto cleanup;
}
if (CMS_final(cms, bd_in, NULL, CMS_NOCERTS | CMS_BINARY) != 1) {
err = -EIO;
goto cleanup;
}
EVP_Digest(opts->insns, opts->insns_sz, opts->excl_prog_hash,
&opts->excl_prog_hash_sz, EVP_sha256(), NULL);
bd_out = BIO_new(BIO_s_mem());
if (!bd_out) {
err = -ENOMEM;
goto cleanup;
}
if (!i2d_CMS_bio_stream(bd_out, cms, NULL, 0)) {
err = -EIO;
goto cleanup;
}
actual_sig_len = BIO_get_mem_data(bd_out, NULL);
if (actual_sig_len <= 0) {
err = -EIO;
goto cleanup;
}
if ((size_t)actual_sig_len > opts->signature_sz) {
err = -ENOSPC;
goto cleanup;
}
if (BIO_read(bd_out, opts->signature, actual_sig_len) != actual_sig_len) {
err = -EIO;
goto cleanup;
}
opts->signature_sz = actual_sig_len;
cleanup:
BIO_free(bd_out);
CMS_ContentInfo_free(cms);
X509_free(x509);
EVP_PKEY_free(private_key);
BIO_free(bd_in);
DISPLAY_OSSL_ERR(err < 0);
return err;
}
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