--- /dev/null
+/*
+ * Copyright (c) 2013, Google Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include "mkimage.h"
+#include <stdio.h>
+#include <string.h>
+#include <image.h>
+#include <time.h>
+#include <openssl/rsa.h>
+#include <openssl/pem.h>
+#include <openssl/err.h>
+#include <openssl/ssl.h>
+#include <openssl/evp.h>
+
+#if OPENSSL_VERSION_NUMBER >= 0x10000000L
+#define HAVE_ERR_REMOVE_THREAD_STATE
+#endif
+
+static int rsa_err(const char *msg)
+{
+ unsigned long sslErr = ERR_get_error();
+
+ fprintf(stderr, "%s", msg);
+ fprintf(stderr, ": %s\n",
+ ERR_error_string(sslErr, 0));
+
+ return -1;
+}
+
+/**
+ * rsa_get_pub_key() - read a public key from a .crt file
+ *
+ * @keydir: Directory containins the key
+ * @name Name of key file (will have a .crt extension)
+ * @rsap Returns RSA object, or NULL on failure
+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
+ */
+static int rsa_get_pub_key(const char *keydir, const char *name, RSA **rsap)
+{
+ char path[1024];
+ EVP_PKEY *key;
+ X509 *cert;
+ RSA *rsa;
+ FILE *f;
+ int ret;
+
+ *rsap = NULL;
+ snprintf(path, sizeof(path), "%s/%s.crt", keydir, name);
+ f = fopen(path, "r");
+ if (!f) {
+ fprintf(stderr, "Couldn't open RSA certificate: '%s': %s\n",
+ path, strerror(errno));
+ return -EACCES;
+ }
+
+ /* Read the certificate */
+ cert = NULL;
+ if (!PEM_read_X509(f, &cert, NULL, NULL)) {
+ rsa_err("Couldn't read certificate");
+ ret = -EINVAL;
+ goto err_cert;
+ }
+
+ /* Get the public key from the certificate. */
+ key = X509_get_pubkey(cert);
+ if (!key) {
+ rsa_err("Couldn't read public key\n");
+ ret = -EINVAL;
+ goto err_pubkey;
+ }
+
+ /* Convert to a RSA_style key. */
+ rsa = EVP_PKEY_get1_RSA(key);
+ if (!rsa) {
+ rsa_err("Couldn't convert to a RSA style key");
+ goto err_rsa;
+ }
+ fclose(f);
+ EVP_PKEY_free(key);
+ X509_free(cert);
+ *rsap = rsa;
+
+ return 0;
+
+err_rsa:
+ EVP_PKEY_free(key);
+err_pubkey:
+ X509_free(cert);
+err_cert:
+ fclose(f);
+ return ret;
+}
+
+/**
+ * rsa_get_priv_key() - read a private key from a .key file
+ *
+ * @keydir: Directory containins the key
+ * @name Name of key file (will have a .key extension)
+ * @rsap Returns RSA object, or NULL on failure
+ * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
+ */
+static int rsa_get_priv_key(const char *keydir, const char *name, RSA **rsap)
+{
+ char path[1024];
+ RSA *rsa;
+ FILE *f;
+
+ *rsap = NULL;
+ snprintf(path, sizeof(path), "%s/%s.key", keydir, name);
+ f = fopen(path, "r");
+ if (!f) {
+ fprintf(stderr, "Couldn't open RSA private key: '%s': %s\n",
+ path, strerror(errno));
+ return -ENOENT;
+ }
+
+ rsa = PEM_read_RSAPrivateKey(f, 0, NULL, path);
+ if (!rsa) {
+ rsa_err("Failure reading private key");
+ fclose(f);
+ return -EPROTO;
+ }
+ fclose(f);
+ *rsap = rsa;
+
+ return 0;
+}
+
+static int rsa_init(void)
+{
+ int ret;
+
+ ret = SSL_library_init();
+ if (!ret) {
+ fprintf(stderr, "Failure to init SSL library\n");
+ return -1;
+ }
+ SSL_load_error_strings();
+
+ OpenSSL_add_all_algorithms();
+ OpenSSL_add_all_digests();
+ OpenSSL_add_all_ciphers();
+
+ return 0;
+}
+
+static void rsa_remove(void)
+{
+ CRYPTO_cleanup_all_ex_data();
+ ERR_free_strings();
+#ifdef HAVE_ERR_REMOVE_THREAD_STATE
+ ERR_remove_thread_state(NULL);
+#else
+ ERR_remove_state(0);
+#endif
+ EVP_cleanup();
+}
+
+static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
+ const struct image_region region[], int region_count,
+ uint8_t **sigp, uint *sig_size)
+{
+ EVP_PKEY *key;
+ EVP_MD_CTX *context;
+ int size, ret = 0;
+ uint8_t *sig;
+ int i;
+
+ key = EVP_PKEY_new();
+ if (!key)
+ return rsa_err("EVP_PKEY object creation failed");
+
+ if (!EVP_PKEY_set1_RSA(key, rsa)) {
+ ret = rsa_err("EVP key setup failed");
+ goto err_set;
+ }
+
+ size = EVP_PKEY_size(key);
+ sig = malloc(size);
+ if (!sig) {
+ fprintf(stderr, "Out of memory for signature (%d bytes)\n",
+ size);
+ ret = -ENOMEM;
+ goto err_alloc;
+ }
+
+ context = EVP_MD_CTX_create();
+ if (!context) {
+ ret = rsa_err("EVP context creation failed");
+ goto err_create;
+ }
+ EVP_MD_CTX_init(context);
+ if (!EVP_SignInit(context, checksum_algo->calculate_sign())) {
+ ret = rsa_err("Signer setup failed");
+ goto err_sign;
+ }
+
+ for (i = 0; i < region_count; i++) {
+ if (!EVP_SignUpdate(context, region[i].data, region[i].size)) {
+ ret = rsa_err("Signing data failed");
+ goto err_sign;
+ }
+ }
+
+ if (!EVP_SignFinal(context, sig, sig_size, key)) {
+ ret = rsa_err("Could not obtain signature");
+ goto err_sign;
+ }
+ EVP_MD_CTX_cleanup(context);
+ EVP_MD_CTX_destroy(context);
+ EVP_PKEY_free(key);
+
+ debug("Got signature: %d bytes, expected %d\n", *sig_size, size);
+ *sigp = sig;
+ *sig_size = size;
+
+ return 0;
+
+err_sign:
+ EVP_MD_CTX_destroy(context);
+err_create:
+ free(sig);
+err_alloc:
+err_set:
+ EVP_PKEY_free(key);
+ return ret;
+}
+
+int rsa_sign(struct image_sign_info *info,
+ const struct image_region region[], int region_count,
+ uint8_t **sigp, uint *sig_len)
+{
+ RSA *rsa;
+ int ret;
+
+ ret = rsa_init();
+ if (ret)
+ return ret;
+
+ ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
+ if (ret)
+ goto err_priv;
+ ret = rsa_sign_with_key(rsa, info->algo->checksum, region,
+ region_count, sigp, sig_len);
+ if (ret)
+ goto err_sign;
+
+ RSA_free(rsa);
+ rsa_remove();
+
+ return ret;
+
+err_sign:
+ RSA_free(rsa);
+err_priv:
+ rsa_remove();
+ return ret;
+}
+
+/*
+ * rsa_get_params(): - Get the important parameters of an RSA public key
+ */
+int rsa_get_params(RSA *key, uint32_t *n0_invp, BIGNUM **modulusp,
+ BIGNUM **r_squaredp)
+{
+ BIGNUM *big1, *big2, *big32, *big2_32;
+ BIGNUM *n, *r, *r_squared, *tmp;
+ BN_CTX *bn_ctx = BN_CTX_new();
+ int ret = 0;
+
+ /* Initialize BIGNUMs */
+ big1 = BN_new();
+ big2 = BN_new();
+ big32 = BN_new();
+ r = BN_new();
+ r_squared = BN_new();
+ tmp = BN_new();
+ big2_32 = BN_new();
+ n = BN_new();
+ if (!big1 || !big2 || !big32 || !r || !r_squared || !tmp || !big2_32 ||
+ !n) {
+ fprintf(stderr, "Out of memory (bignum)\n");
+ return -ENOMEM;
+ }
+
+ if (!BN_copy(n, key->n) || !BN_set_word(big1, 1L) ||
+ !BN_set_word(big2, 2L) || !BN_set_word(big32, 32L))
+ ret = -1;
+
+ /* big2_32 = 2^32 */
+ if (!BN_exp(big2_32, big2, big32, bn_ctx))
+ ret = -1;
+
+ /* Calculate n0_inv = -1 / n[0] mod 2^32 */
+ if (!BN_mod_inverse(tmp, n, big2_32, bn_ctx) ||
+ !BN_sub(tmp, big2_32, tmp))
+ ret = -1;
+ *n0_invp = BN_get_word(tmp);
+
+ /* Calculate R = 2^(# of key bits) */
+ if (!BN_set_word(tmp, BN_num_bits(n)) ||
+ !BN_exp(r, big2, tmp, bn_ctx))
+ ret = -1;
+
+ /* Calculate r_squared = R^2 mod n */
+ if (!BN_copy(r_squared, r) ||
+ !BN_mul(tmp, r_squared, r, bn_ctx) ||
+ !BN_mod(r_squared, tmp, n, bn_ctx))
+ ret = -1;
+
+ *modulusp = n;
+ *r_squaredp = r_squared;
+
+ BN_free(big1);
+ BN_free(big2);
+ BN_free(big32);
+ BN_free(r);
+ BN_free(tmp);
+ BN_free(big2_32);
+ if (ret) {
+ fprintf(stderr, "Bignum operations failed\n");
+ return -ENOMEM;
+ }
+
+ return ret;
+}
+
+static int fdt_add_bignum(void *blob, int noffset, const char *prop_name,
+ BIGNUM *num, int num_bits)
+{
+ int nwords = num_bits / 32;
+ int size;
+ uint32_t *buf, *ptr;
+ BIGNUM *tmp, *big2, *big32, *big2_32;
+ BN_CTX *ctx;
+ int ret;
+
+ tmp = BN_new();
+ big2 = BN_new();
+ big32 = BN_new();
+ big2_32 = BN_new();
+ if (!tmp || !big2 || !big32 || !big2_32) {
+ fprintf(stderr, "Out of memory (bignum)\n");
+ return -ENOMEM;
+ }
+ ctx = BN_CTX_new();
+ if (!tmp) {
+ fprintf(stderr, "Out of memory (bignum context)\n");
+ return -ENOMEM;
+ }
+ BN_set_word(big2, 2L);
+ BN_set_word(big32, 32L);
+ BN_exp(big2_32, big2, big32, ctx); /* B = 2^32 */
+
+ size = nwords * sizeof(uint32_t);
+ buf = malloc(size);
+ if (!buf) {
+ fprintf(stderr, "Out of memory (%d bytes)\n", size);
+ return -ENOMEM;
+ }
+
+ /* Write out modulus as big endian array of integers */
+ for (ptr = buf + nwords - 1; ptr >= buf; ptr--) {
+ BN_mod(tmp, num, big2_32, ctx); /* n = N mod B */
+ *ptr = cpu_to_fdt32(BN_get_word(tmp));
+ BN_rshift(num, num, 32); /* N = N/B */
+ }
+
+ ret = fdt_setprop(blob, noffset, prop_name, buf, size);
+ if (ret) {
+ fprintf(stderr, "Failed to write public key to FIT\n");
+ return -ENOSPC;
+ }
+ free(buf);
+ BN_free(tmp);
+ BN_free(big2);
+ BN_free(big32);
+ BN_free(big2_32);
+
+ return ret;
+}
+
+int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
+{
+ BIGNUM *modulus, *r_squared;
+ uint32_t n0_inv;
+ int parent, node;
+ char name[100];
+ int ret;
+ int bits;
+ RSA *rsa;
+
+ debug("%s: Getting verification data\n", __func__);
+ ret = rsa_get_pub_key(info->keydir, info->keyname, &rsa);
+ if (ret)
+ return ret;
+ ret = rsa_get_params(rsa, &n0_inv, &modulus, &r_squared);
+ if (ret)
+ return ret;
+ bits = BN_num_bits(modulus);
+ parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
+ if (parent == -FDT_ERR_NOTFOUND) {
+ parent = fdt_add_subnode(keydest, 0, FIT_SIG_NODENAME);
+ if (parent < 0) {
+ fprintf(stderr, "Couldn't create signature node: %s\n",
+ fdt_strerror(parent));
+ return -EINVAL;
+ }
+ }
+
+ /* Either create or overwrite the named key node */
+ snprintf(name, sizeof(name), "key-%s", info->keyname);
+ node = fdt_subnode_offset(keydest, parent, name);
+ if (node == -FDT_ERR_NOTFOUND) {
+ node = fdt_add_subnode(keydest, parent, name);
+ if (node < 0) {
+ fprintf(stderr, "Could not create key subnode: %s\n",
+ fdt_strerror(node));
+ return -EINVAL;
+ }
+ } else if (node < 0) {
+ fprintf(stderr, "Cannot select keys parent: %s\n",
+ fdt_strerror(node));
+ return -ENOSPC;
+ }
+
+ ret = fdt_setprop_string(keydest, node, "key-name-hint",
+ info->keyname);
+ ret |= fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
+ ret |= fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
+ ret |= fdt_add_bignum(keydest, node, "rsa,modulus", modulus, bits);
+ ret |= fdt_add_bignum(keydest, node, "rsa,r-squared", r_squared, bits);
+ ret |= fdt_setprop_string(keydest, node, FIT_ALGO_PROP,
+ info->algo->name);
+ if (info->require_keys) {
+ fdt_setprop_string(keydest, node, "required",
+ info->require_keys);
+ }
+ BN_free(modulus);
+ BN_free(r_squared);
+ if (ret)
+ return -EIO;
+
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff