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u-boot/lib/rsa/rsa-sign.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

777 lines
16 KiB
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2013, Google Inc.
*/
#include "mkimage.h"
#include <stdio.h>
#include <string.h>
#include <image.h>
#include <time.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/evp.h>
#include <openssl/engine.h>
#if OPENSSL_VERSION_NUMBER >= 0x10000000L
#define HAVE_ERR_REMOVE_THREAD_STATE
#endif
#if OPENSSL_VERSION_NUMBER < 0x10100000L
static void RSA_get0_key(const RSA *r,
const BIGNUM **n, const BIGNUM **e, const BIGNUM **d)
{
if (n != NULL)
*n = r->n;
if (e != NULL)
*e = r->e;
if (d != NULL)
*d = r->d;
}
#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_pem_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_pem_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");
ret = -EINVAL;
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_engine_get_pub_key() - read a public key from given engine
*
* @keydir: Key prefix
* @name Name of key
* @engine Engine to use
* @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_engine_get_pub_key(const char *keydir, const char *name,
ENGINE *engine, RSA **rsap)
{
const char *engine_id;
char key_id[1024];
EVP_PKEY *key;
RSA *rsa;
int ret;
*rsap = NULL;
engine_id = ENGINE_get_id(engine);
if (engine_id && !strcmp(engine_id, "pkcs11")) {
if (keydir)
snprintf(key_id, sizeof(key_id),
"pkcs11:%s;object=%s;type=public",
keydir, name);
else
snprintf(key_id, sizeof(key_id),
"pkcs11:object=%s;type=public",
name);
} else {
fprintf(stderr, "Engine not supported\n");
return -ENOTSUP;
}
key = ENGINE_load_public_key(engine, key_id, NULL, NULL);
if (!key)
return rsa_err("Failure loading public key from engine");
/* Convert to a RSA_style key. */
rsa = EVP_PKEY_get1_RSA(key);
if (!rsa) {
rsa_err("Couldn't convert to a RSA style key");
ret = -EINVAL;
goto err_rsa;
}
EVP_PKEY_free(key);
*rsap = rsa;
return 0;
err_rsa:
EVP_PKEY_free(key);
return ret;
}
/**
* rsa_get_pub_key() - read a public key
*
* @keydir: Directory containing the key (PEM file) or key prefix (engine)
* @name Name of key file (will have a .crt extension)
* @engine Engine to use
* @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,
ENGINE *engine, RSA **rsap)
{
if (engine)
return rsa_engine_get_pub_key(keydir, name, engine, rsap);
return rsa_pem_get_pub_key(keydir, name, rsap);
}
/**
* rsa_pem_get_priv_key() - read a private key from a .key file
*
* @keydir: Directory containing 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_pem_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;
}
/**
* rsa_engine_get_priv_key() - read a private key from given engine
*
* @keydir: Key prefix
* @name Name of key
* @engine Engine to use
* @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_engine_get_priv_key(const char *keydir, const char *name,
ENGINE *engine, RSA **rsap)
{
const char *engine_id;
char key_id[1024];
EVP_PKEY *key;
RSA *rsa;
int ret;
*rsap = NULL;
engine_id = ENGINE_get_id(engine);
if (engine_id && !strcmp(engine_id, "pkcs11")) {
if (keydir)
snprintf(key_id, sizeof(key_id),
"pkcs11:%s;object=%s;type=private",
keydir, name);
else
snprintf(key_id, sizeof(key_id),
"pkcs11:object=%s;type=private",
name);
} else {
fprintf(stderr, "Engine not supported\n");
return -ENOTSUP;
}
key = ENGINE_load_private_key(engine, key_id, NULL, NULL);
if (!key)
return rsa_err("Failure loading private key from engine");
/* Convert to a RSA_style key. */
rsa = EVP_PKEY_get1_RSA(key);
if (!rsa) {
rsa_err("Couldn't convert to a RSA style key");
ret = -EINVAL;
goto err_rsa;
}
EVP_PKEY_free(key);
*rsap = rsa;
return 0;
err_rsa:
EVP_PKEY_free(key);
return ret;
}
/**
* rsa_get_priv_key() - read a private key
*
* @keydir: Directory containing the key (PEM file) or key prefix (engine)
* @name Name of key
* @engine Engine to use for signing
* @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,
ENGINE *engine, RSA **rsap)
{
if (engine)
return rsa_engine_get_priv_key(keydir, name, engine, rsap);
return rsa_pem_get_priv_key(keydir, name, rsap);
}
static int rsa_init(void)
{
int ret;
#if OPENSSL_VERSION_NUMBER < 0x10100000L
ret = SSL_library_init();
#else
ret = OPENSSL_init_ssl(0, NULL);
#endif
if (!ret) {
fprintf(stderr, "Failure to init SSL library\n");
return -1;
}
#if OPENSSL_VERSION_NUMBER < 0x10100000L
SSL_load_error_strings();
OpenSSL_add_all_algorithms();
OpenSSL_add_all_digests();
OpenSSL_add_all_ciphers();
#endif
return 0;
}
static int rsa_engine_init(const char *engine_id, ENGINE **pe)
{
ENGINE *e;
int ret;
ENGINE_load_builtin_engines();
e = ENGINE_by_id(engine_id);
if (!e) {
fprintf(stderr, "Engine isn't available\n");
ret = -1;
goto err_engine_by_id;
}
if (!ENGINE_init(e)) {
fprintf(stderr, "Couldn't initialize engine\n");
ret = -1;
goto err_engine_init;
}
if (!ENGINE_set_default_RSA(e)) {
fprintf(stderr, "Couldn't set engine as default for RSA\n");
ret = -1;
goto err_set_rsa;
}
*pe = e;
return 0;
err_set_rsa:
ENGINE_finish(e);
err_engine_init:
ENGINE_free(e);
err_engine_by_id:
#if OPENSSL_VERSION_NUMBER < 0x10100000L
ENGINE_cleanup();
#endif
return ret;
}
static void rsa_remove(void)
{
#if OPENSSL_VERSION_NUMBER < 0x10100000L
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();
#endif
}
static void rsa_engine_remove(ENGINE *e)
{
if (e) {
ENGINE_finish(e);
ENGINE_free(e);
}
}
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;
}
#if OPENSSL_VERSION_NUMBER < 0x10100000L
EVP_MD_CTX_cleanup(context);
#else
EVP_MD_CTX_reset(context);
#endif
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;
ENGINE *e = NULL;
int ret;
ret = rsa_init();
if (ret)
return ret;
if (info->engine_id) {
ret = rsa_engine_init(info->engine_id, &e);
if (ret)
goto err_engine;
}
ret = rsa_get_priv_key(info->keydir, info->keyname, e, &rsa);
if (ret)
goto err_priv;
ret = rsa_sign_with_key(rsa, info->checksum, region,
region_count, sigp, sig_len);
if (ret)
goto err_sign;
RSA_free(rsa);
if (info->engine_id)
rsa_engine_remove(e);
rsa_remove();
return ret;
err_sign:
RSA_free(rsa);
err_priv:
if (info->engine_id)
rsa_engine_remove(e);
err_engine:
rsa_remove();
return ret;
}
/*
* rsa_get_exponent(): - Get the public exponent from an RSA key
*/
static int rsa_get_exponent(RSA *key, uint64_t *e)
{
int ret;
BIGNUM *bn_te;
const BIGNUM *key_e;
uint64_t te;
ret = -EINVAL;
bn_te = NULL;
if (!e)
goto cleanup;
RSA_get0_key(key, NULL, &key_e, NULL);
if (BN_num_bits(key_e) > 64)
goto cleanup;
*e = BN_get_word(key_e);
if (BN_num_bits(key_e) < 33) {
ret = 0;
goto cleanup;
}
bn_te = BN_dup(key_e);
if (!bn_te)
goto cleanup;
if (!BN_rshift(bn_te, bn_te, 32))
goto cleanup;
if (!BN_mask_bits(bn_te, 32))
goto cleanup;
te = BN_get_word(bn_te);
te <<= 32;
*e |= te;
ret = 0;
cleanup:
if (bn_te)
BN_free(bn_te);
return ret;
}
/*
* rsa_get_params(): - Get the important parameters of an RSA public key
*/
int rsa_get_params(RSA *key, uint64_t *exponent, uint32_t *n0_invp,
BIGNUM **modulusp, BIGNUM **r_squaredp)
{
BIGNUM *big1, *big2, *big32, *big2_32;
BIGNUM *n, *r, *r_squared, *tmp;
const BIGNUM *key_n;
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 (0 != rsa_get_exponent(key, exponent))
ret = -1;
RSA_get0_key(key, &key_n, NULL, NULL);
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 */
}
/*
* We try signing with successively increasing size values, so this
* might fail several times
*/
ret = fdt_setprop(blob, noffset, prop_name, buf, size);
if (ret)
return -FDT_ERR_NOSPACE;
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;
uint64_t exponent;
uint32_t n0_inv;
int parent, node;
char name[100];
int ret;
int bits;
RSA *rsa;
ENGINE *e = NULL;
debug("%s: Getting verification data\n", __func__);
if (info->engine_id) {
ret = rsa_engine_init(info->engine_id, &e);
if (ret)
return ret;
}
ret = rsa_get_pub_key(info->keydir, info->keyname, e, &rsa);
if (ret)
goto err_get_pub_key;
ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus, &r_squared);
if (ret)
goto err_get_params;
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) {
ret = parent;
if (ret != -FDT_ERR_NOSPACE) {
fprintf(stderr, "Couldn't create signature node: %s\n",
fdt_strerror(parent));
}
}
}
if (ret)
goto done;
/* 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) {
ret = node;
if (ret != -FDT_ERR_NOSPACE) {
fprintf(stderr, "Could not create key subnode: %s\n",
fdt_strerror(node));
}
}
} else if (node < 0) {
fprintf(stderr, "Cannot select keys parent: %s\n",
fdt_strerror(node));
ret = node;
}
if (!ret) {
ret = fdt_setprop_string(keydest, node, "key-name-hint",
info->keyname);
}
if (!ret)
ret = fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
if (!ret)
ret = fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
if (!ret) {
ret = fdt_setprop_u64(keydest, node, "rsa,exponent", exponent);
}
if (!ret) {
ret = fdt_add_bignum(keydest, node, "rsa,modulus", modulus,
bits);
}
if (!ret) {
ret = fdt_add_bignum(keydest, node, "rsa,r-squared", r_squared,
bits);
}
if (!ret) {
ret = fdt_setprop_string(keydest, node, FIT_ALGO_PROP,
info->name);
}
if (!ret && info->require_keys) {
ret = fdt_setprop_string(keydest, node, "required",
info->require_keys);
}
done:
BN_free(modulus);
BN_free(r_squared);
if (ret)
ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
err_get_params:
RSA_free(rsa);
err_get_pub_key:
if (info->engine_id)
rsa_engine_remove(e);
return ret;
}
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