mirror of
https://github.com/u-boot/u-boot.git
synced 2024-12-09 20:53:40 +08:00
81eff51047
Modify function to support any salt length instead of max length only. Function now detects salt length by parsing the content of db buffer. Note that it works with (but is not limited to) zero-length, digest-length and max-length Signed-off-by: SESA644425 <gioja.hermann@non.se.com> Reviewed-by: Simon Glass <sjg@chromium.org>
613 lines
15 KiB
C
613 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* Copyright (c) 2013, Google Inc.
|
|
*/
|
|
|
|
#ifndef USE_HOSTCC
|
|
#include <common.h>
|
|
#include <fdtdec.h>
|
|
#include <log.h>
|
|
#include <malloc.h>
|
|
#include <asm/types.h>
|
|
#include <asm/byteorder.h>
|
|
#include <linux/errno.h>
|
|
#include <asm/types.h>
|
|
#include <asm/unaligned.h>
|
|
#include <dm.h>
|
|
#else
|
|
#include "fdt_host.h"
|
|
#include "mkimage.h"
|
|
#include <fdt_support.h>
|
|
#endif
|
|
#include <linux/kconfig.h>
|
|
#include <u-boot/rsa-mod-exp.h>
|
|
#include <u-boot/rsa.h>
|
|
|
|
#ifndef __UBOOT__
|
|
/*
|
|
* NOTE:
|
|
* Since host tools, like mkimage, make use of openssl library for
|
|
* RSA encryption, rsa_verify_with_pkey()/rsa_gen_key_prop() are
|
|
* of no use and should not be compiled in.
|
|
* So just turn off CONFIG_RSA_VERIFY_WITH_PKEY.
|
|
*/
|
|
|
|
#undef CONFIG_RSA_VERIFY_WITH_PKEY
|
|
#endif
|
|
|
|
/* Default public exponent for backward compatibility */
|
|
#define RSA_DEFAULT_PUBEXP 65537
|
|
|
|
/**
|
|
* rsa_verify_padding() - Verify RSA message padding is valid
|
|
*
|
|
* Verify a RSA message's padding is consistent with PKCS1.5
|
|
* padding as described in the RSA PKCS#1 v2.1 standard.
|
|
*
|
|
* @msg: Padded message
|
|
* @pad_len: Number of expected padding bytes
|
|
* @algo: Checksum algo structure having information on DER encoding etc.
|
|
* Return: 0 on success, != 0 on failure
|
|
*/
|
|
static int rsa_verify_padding(const uint8_t *msg, const int pad_len,
|
|
struct checksum_algo *algo)
|
|
{
|
|
int ff_len;
|
|
int ret;
|
|
|
|
/* first byte must be 0x00 */
|
|
ret = *msg++;
|
|
/* second byte must be 0x01 */
|
|
ret |= *msg++ ^ 0x01;
|
|
/* next ff_len bytes must be 0xff */
|
|
ff_len = pad_len - algo->der_len - 3;
|
|
ret |= *msg ^ 0xff;
|
|
ret |= memcmp(msg, msg+1, ff_len-1);
|
|
msg += ff_len;
|
|
/* next byte must be 0x00 */
|
|
ret |= *msg++;
|
|
/* next der_len bytes must match der_prefix */
|
|
ret |= memcmp(msg, algo->der_prefix, algo->der_len);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int padding_pkcs_15_verify(struct image_sign_info *info,
|
|
const uint8_t *msg, int msg_len,
|
|
const uint8_t *hash, int hash_len)
|
|
{
|
|
struct checksum_algo *checksum = info->checksum;
|
|
int ret, pad_len = msg_len - checksum->checksum_len;
|
|
|
|
/* Check pkcs1.5 padding bytes */
|
|
ret = rsa_verify_padding(msg, pad_len, checksum);
|
|
if (ret) {
|
|
debug("In RSAVerify(): Padding check failed!\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Check hash */
|
|
if (memcmp((uint8_t *)msg + pad_len, hash, msg_len - pad_len)) {
|
|
debug("In RSAVerify(): Hash check failed!\n");
|
|
return -EACCES;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifndef USE_HOSTCC
|
|
U_BOOT_PADDING_ALGO(pkcs_15) = {
|
|
.name = "pkcs-1.5",
|
|
.verify = padding_pkcs_15_verify,
|
|
};
|
|
#endif
|
|
|
|
#if CONFIG_IS_ENABLED(FIT_RSASSA_PSS)
|
|
static void u32_i2osp(uint32_t val, uint8_t *buf)
|
|
{
|
|
buf[0] = (uint8_t)((val >> 24) & 0xff);
|
|
buf[1] = (uint8_t)((val >> 16) & 0xff);
|
|
buf[2] = (uint8_t)((val >> 8) & 0xff);
|
|
buf[3] = (uint8_t)((val >> 0) & 0xff);
|
|
}
|
|
|
|
/**
|
|
* mask_generation_function1() - generate an octet string
|
|
*
|
|
* Generate an octet string used to check rsa signature.
|
|
* It use an input octet string and a hash function.
|
|
*
|
|
* @checksum: A Hash function
|
|
* @seed: Specifies an input variable octet string
|
|
* @seed_len: Size of the input octet string
|
|
* @output: Specifies the output octet string
|
|
* @output_len: Size of the output octet string
|
|
* Return: 0 if the octet string was correctly generated, others on error
|
|
*/
|
|
static int mask_generation_function1(struct checksum_algo *checksum,
|
|
const uint8_t *seed, int seed_len,
|
|
uint8_t *output, int output_len)
|
|
{
|
|
struct image_region region[2];
|
|
int ret = 0, i, i_output = 0, region_count = 2;
|
|
uint32_t counter = 0;
|
|
uint8_t buf_counter[4], *tmp;
|
|
int hash_len = checksum->checksum_len;
|
|
|
|
memset(output, 0, output_len);
|
|
|
|
region[0].data = seed;
|
|
region[0].size = seed_len;
|
|
region[1].data = &buf_counter[0];
|
|
region[1].size = 4;
|
|
|
|
tmp = malloc(hash_len);
|
|
if (!tmp) {
|
|
debug("%s: can't allocate array tmp\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
while (i_output < output_len) {
|
|
u32_i2osp(counter, &buf_counter[0]);
|
|
|
|
ret = checksum->calculate(checksum->name,
|
|
region, region_count,
|
|
tmp);
|
|
if (ret < 0) {
|
|
debug("%s: Error in checksum calculation\n", __func__);
|
|
goto out;
|
|
}
|
|
|
|
i = 0;
|
|
while ((i_output < output_len) && (i < hash_len)) {
|
|
output[i_output] = tmp[i];
|
|
i_output++;
|
|
i++;
|
|
}
|
|
|
|
counter++;
|
|
}
|
|
|
|
out:
|
|
free(tmp);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int compute_hash_prime(struct checksum_algo *checksum,
|
|
const uint8_t *pad, int pad_len,
|
|
const uint8_t *hash, int hash_len,
|
|
const uint8_t *salt, int salt_len,
|
|
uint8_t *hprime)
|
|
{
|
|
struct image_region region[3];
|
|
int ret, region_count = 3;
|
|
|
|
region[0].data = pad;
|
|
region[0].size = pad_len;
|
|
region[1].data = hash;
|
|
region[1].size = hash_len;
|
|
region[2].data = salt;
|
|
region[2].size = salt_len;
|
|
|
|
ret = checksum->calculate(checksum->name, region, region_count, hprime);
|
|
if (ret < 0) {
|
|
debug("%s: Error in checksum calculation\n", __func__);
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* padding_pss_verify() - verify the pss padding of a signature
|
|
*
|
|
* Works with any salt length
|
|
*
|
|
* msg is a concatenation of : masked_db + h + 0xbc
|
|
* Once unmasked, db is a concatenation of : [0x00]* + 0x01 + salt
|
|
* Length of 0-padding at begin of db depends on salt length.
|
|
*
|
|
* @info: Specifies key and FIT information
|
|
* @msg: byte array of message, len equal to msg_len
|
|
* @msg_len: Message length
|
|
* @hash: Pointer to the expected hash
|
|
* @hash_len: Length of the hash
|
|
*/
|
|
int padding_pss_verify(struct image_sign_info *info,
|
|
const uint8_t *msg, int msg_len,
|
|
const uint8_t *hash, int hash_len)
|
|
{
|
|
const uint8_t *masked_db = NULL;
|
|
uint8_t *db_mask = NULL;
|
|
uint8_t *db = NULL;
|
|
int db_len = msg_len - hash_len - 1;
|
|
const uint8_t *h = NULL;
|
|
uint8_t *hprime = NULL;
|
|
int h_len = hash_len;
|
|
uint8_t *db_nopad = NULL, *salt = NULL;
|
|
int db_padlen, salt_len;
|
|
uint8_t pad_zero[8] = { 0 };
|
|
int ret, i, leftmost_bits = 1;
|
|
uint8_t leftmost_mask;
|
|
struct checksum_algo *checksum = info->checksum;
|
|
|
|
/* first, allocate everything */
|
|
db_mask = malloc(db_len);
|
|
db = malloc(db_len);
|
|
hprime = malloc(hash_len);
|
|
if (!db_mask || !db || !hprime) {
|
|
printf("%s: can't allocate some buffer\n", __func__);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
/* step 4: check if the last byte is 0xbc */
|
|
if (msg[msg_len - 1] != 0xbc) {
|
|
printf("%s: invalid pss padding (0xbc is missing)\n", __func__);
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* step 5 */
|
|
masked_db = &msg[0];
|
|
h = &msg[db_len];
|
|
|
|
/* step 6 */
|
|
leftmost_mask = (0xff >> (8 - leftmost_bits)) << (8 - leftmost_bits);
|
|
if (masked_db[0] & leftmost_mask) {
|
|
printf("%s: invalid pss padding ", __func__);
|
|
printf("(leftmost bit of maskedDB not zero)\n");
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* step 7 */
|
|
mask_generation_function1(checksum, h, h_len, db_mask, db_len);
|
|
|
|
/* step 8 */
|
|
for (i = 0; i < db_len; i++)
|
|
db[i] = masked_db[i] ^ db_mask[i];
|
|
|
|
/* step 9 */
|
|
db[0] &= 0xff >> leftmost_bits;
|
|
|
|
/* step 10 */
|
|
db_padlen = 0;
|
|
while (db[db_padlen] == 0x00 && db_padlen < (db_len - 1))
|
|
db_padlen++;
|
|
db_nopad = &db[db_padlen];
|
|
if (db_nopad[0] != 0x01) {
|
|
printf("%s: invalid pss padding ", __func__);
|
|
printf("(leftmost byte of db after 0-padding isn't 0x01)\n");
|
|
ret = EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* step 11 */
|
|
salt_len = db_len - db_padlen - 1;
|
|
salt = &db_nopad[1];
|
|
|
|
/* step 12 & 13 */
|
|
compute_hash_prime(checksum, pad_zero, 8,
|
|
hash, hash_len,
|
|
salt, salt_len, hprime);
|
|
|
|
/* step 14 */
|
|
ret = memcmp(h, hprime, hash_len);
|
|
|
|
out:
|
|
free(hprime);
|
|
free(db);
|
|
free(db_mask);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifndef USE_HOSTCC
|
|
U_BOOT_PADDING_ALGO(pss) = {
|
|
.name = "pss",
|
|
.verify = padding_pss_verify,
|
|
};
|
|
#endif
|
|
|
|
#endif
|
|
|
|
/**
|
|
* rsa_verify_key() - Verify a signature against some data using RSA Key
|
|
*
|
|
* Verify a RSA PKCS1.5 signature against an expected hash using
|
|
* the RSA Key properties in prop structure.
|
|
*
|
|
* @info: Specifies key and FIT information
|
|
* @prop: Specifies key
|
|
* @sig: Signature
|
|
* @sig_len: Number of bytes in signature
|
|
* @hash: Pointer to the expected hash
|
|
* @key_len: Number of bytes in rsa key
|
|
* Return: 0 if verified, -ve on error
|
|
*/
|
|
static int rsa_verify_key(struct image_sign_info *info,
|
|
struct key_prop *prop, const uint8_t *sig,
|
|
const uint32_t sig_len, const uint8_t *hash,
|
|
const uint32_t key_len)
|
|
{
|
|
int ret;
|
|
#if !defined(USE_HOSTCC)
|
|
struct udevice *mod_exp_dev;
|
|
#endif
|
|
struct checksum_algo *checksum = info->checksum;
|
|
struct padding_algo *padding = info->padding;
|
|
int hash_len;
|
|
|
|
if (!prop || !sig || !hash || !checksum || !padding)
|
|
return -EIO;
|
|
|
|
if (sig_len != (prop->num_bits / 8)) {
|
|
debug("Signature is of incorrect length %d\n", sig_len);
|
|
return -EINVAL;
|
|
}
|
|
|
|
debug("Checksum algorithm: %s", checksum->name);
|
|
|
|
/* Sanity check for stack size */
|
|
if (sig_len > RSA_MAX_SIG_BITS / 8) {
|
|
debug("Signature length %u exceeds maximum %d\n", sig_len,
|
|
RSA_MAX_SIG_BITS / 8);
|
|
return -EINVAL;
|
|
}
|
|
|
|
uint8_t buf[sig_len];
|
|
hash_len = checksum->checksum_len;
|
|
|
|
#if !defined(USE_HOSTCC)
|
|
ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
|
|
if (ret) {
|
|
printf("RSA: Can't find Modular Exp implementation\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = rsa_mod_exp(mod_exp_dev, sig, sig_len, prop, buf);
|
|
#else
|
|
ret = rsa_mod_exp_sw(sig, sig_len, prop, buf);
|
|
#endif
|
|
if (ret) {
|
|
debug("Error in Modular exponentation\n");
|
|
return ret;
|
|
}
|
|
|
|
ret = padding->verify(info, buf, key_len, hash, hash_len);
|
|
if (ret) {
|
|
debug("In RSAVerify(): padding check failed!\n");
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* rsa_verify_with_pkey() - Verify a signature against some data using
|
|
* only modulus and exponent as RSA key properties.
|
|
* @info: Specifies key information
|
|
* @hash: Pointer to the expected hash
|
|
* @sig: Signature
|
|
* @sig_len: Number of bytes in signature
|
|
*
|
|
* Parse a RSA public key blob in DER format pointed to in @info and fill
|
|
* a key_prop structure with properties of the key. Then verify a RSA PKCS1.5
|
|
* signature against an expected hash using the calculated properties.
|
|
*
|
|
* Return 0 if verified, -ve on error
|
|
*/
|
|
int rsa_verify_with_pkey(struct image_sign_info *info,
|
|
const void *hash, uint8_t *sig, uint sig_len)
|
|
{
|
|
struct key_prop *prop;
|
|
int ret;
|
|
|
|
if (!CONFIG_IS_ENABLED(RSA_VERIFY_WITH_PKEY))
|
|
return -EACCES;
|
|
|
|
/* Public key is self-described to fill key_prop */
|
|
ret = rsa_gen_key_prop(info->key, info->keylen, &prop);
|
|
if (ret) {
|
|
debug("Generating necessary parameter for decoding failed\n");
|
|
return ret;
|
|
}
|
|
|
|
ret = rsa_verify_key(info, prop, sig, sig_len, hash,
|
|
info->crypto->key_len);
|
|
|
|
rsa_free_key_prop(prop);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
|
|
/**
|
|
* rsa_verify_with_keynode() - Verify a signature against some data using
|
|
* information in node with prperties of RSA Key like modulus, exponent etc.
|
|
*
|
|
* Parse sign-node and fill a key_prop structure with properties of the
|
|
* key. Verify a RSA PKCS1.5 signature against an expected hash using
|
|
* the properties parsed
|
|
*
|
|
* @info: Specifies key and FIT information
|
|
* @hash: Pointer to the expected hash
|
|
* @sig: Signature
|
|
* @sig_len: Number of bytes in signature
|
|
* @node: Node having the RSA Key properties
|
|
* Return: 0 if verified, -ve on error
|
|
*/
|
|
static int rsa_verify_with_keynode(struct image_sign_info *info,
|
|
const void *hash, uint8_t *sig,
|
|
uint sig_len, int node)
|
|
{
|
|
const void *blob = info->fdt_blob;
|
|
struct key_prop prop;
|
|
int length;
|
|
int ret = 0;
|
|
const char *algo;
|
|
|
|
if (node < 0) {
|
|
debug("%s: Skipping invalid node", __func__);
|
|
return -EBADF;
|
|
}
|
|
|
|
algo = fdt_getprop(blob, node, "algo", NULL);
|
|
if (strcmp(info->name, algo)) {
|
|
debug("%s: Wrong algo: have %s, expected %s", __func__,
|
|
info->name, algo);
|
|
return -EFAULT;
|
|
}
|
|
|
|
prop.num_bits = fdtdec_get_int(blob, node, "rsa,num-bits", 0);
|
|
|
|
prop.n0inv = fdtdec_get_int(blob, node, "rsa,n0-inverse", 0);
|
|
|
|
prop.public_exponent = fdt_getprop(blob, node, "rsa,exponent", &length);
|
|
if (!prop.public_exponent || length < sizeof(uint64_t))
|
|
prop.public_exponent = NULL;
|
|
|
|
prop.exp_len = sizeof(uint64_t);
|
|
|
|
prop.modulus = fdt_getprop(blob, node, "rsa,modulus", NULL);
|
|
|
|
prop.rr = fdt_getprop(blob, node, "rsa,r-squared", NULL);
|
|
|
|
if (!prop.num_bits || !prop.modulus || !prop.rr) {
|
|
debug("%s: Missing RSA key info", __func__);
|
|
return -EFAULT;
|
|
}
|
|
|
|
ret = rsa_verify_key(info, &prop, sig, sig_len, hash,
|
|
info->crypto->key_len);
|
|
|
|
return ret;
|
|
}
|
|
#else
|
|
static int rsa_verify_with_keynode(struct image_sign_info *info,
|
|
const void *hash, uint8_t *sig,
|
|
uint sig_len, int node)
|
|
{
|
|
return -EACCES;
|
|
}
|
|
#endif
|
|
|
|
int rsa_verify_hash(struct image_sign_info *info,
|
|
const uint8_t *hash, uint8_t *sig, uint sig_len)
|
|
{
|
|
int ret = -EACCES;
|
|
|
|
if (CONFIG_IS_ENABLED(RSA_VERIFY_WITH_PKEY) && !info->fdt_blob) {
|
|
/* don't rely on fdt properties */
|
|
ret = rsa_verify_with_pkey(info, hash, sig, sig_len);
|
|
if (ret)
|
|
debug("%s: rsa_verify_with_pkey() failed\n", __func__);
|
|
return ret;
|
|
}
|
|
|
|
if (CONFIG_IS_ENABLED(FIT_SIGNATURE)) {
|
|
const void *blob = info->fdt_blob;
|
|
int ndepth, noffset;
|
|
int sig_node, node;
|
|
char name[100];
|
|
|
|
sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
|
|
if (sig_node < 0) {
|
|
debug("%s: No signature node found\n", __func__);
|
|
return -ENOENT;
|
|
}
|
|
|
|
/* See if we must use a particular key */
|
|
if (info->required_keynode != -1) {
|
|
ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
|
|
info->required_keynode);
|
|
if (ret)
|
|
debug("%s: Failed to verify required_keynode\n",
|
|
__func__);
|
|
return ret;
|
|
}
|
|
|
|
/* Look for a key that matches our hint */
|
|
snprintf(name, sizeof(name), "key-%s", info->keyname);
|
|
node = fdt_subnode_offset(blob, sig_node, name);
|
|
ret = rsa_verify_with_keynode(info, hash, sig, sig_len, node);
|
|
if (!ret)
|
|
return ret;
|
|
debug("%s: Could not verify key '%s', trying all\n", __func__,
|
|
name);
|
|
|
|
/* No luck, so try each of the keys in turn */
|
|
for (ndepth = 0, noffset = fdt_next_node(blob, sig_node,
|
|
&ndepth);
|
|
(noffset >= 0) && (ndepth > 0);
|
|
noffset = fdt_next_node(blob, noffset, &ndepth)) {
|
|
if (ndepth == 1 && noffset != node) {
|
|
ret = rsa_verify_with_keynode(info, hash,
|
|
sig, sig_len,
|
|
noffset);
|
|
if (!ret)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
debug("%s: Failed to verify by any means\n", __func__);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int rsa_verify(struct image_sign_info *info,
|
|
const struct image_region region[], int region_count,
|
|
uint8_t *sig, uint sig_len)
|
|
{
|
|
/* Reserve memory for maximum checksum-length */
|
|
uint8_t hash[info->crypto->key_len];
|
|
int ret;
|
|
|
|
/*
|
|
* Verify that the checksum-length does not exceed the
|
|
* rsa-signature-length
|
|
*/
|
|
if (info->checksum->checksum_len >
|
|
info->crypto->key_len) {
|
|
debug("%s: invalid checksum-algorithm %s for %s\n",
|
|
__func__, info->checksum->name, info->crypto->name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Calculate checksum with checksum-algorithm */
|
|
ret = info->checksum->calculate(info->checksum->name,
|
|
region, region_count, hash);
|
|
if (ret < 0) {
|
|
debug("%s: Error in checksum calculation\n", __func__);
|
|
return -EINVAL;
|
|
}
|
|
|
|
return rsa_verify_hash(info, hash, sig, sig_len);
|
|
}
|
|
|
|
#ifndef USE_HOSTCC
|
|
|
|
U_BOOT_CRYPTO_ALGO(rsa2048) = {
|
|
.name = "rsa2048",
|
|
.key_len = RSA2048_BYTES,
|
|
.verify = rsa_verify,
|
|
};
|
|
|
|
U_BOOT_CRYPTO_ALGO(rsa3072) = {
|
|
.name = "rsa3072",
|
|
.key_len = RSA3072_BYTES,
|
|
.verify = rsa_verify,
|
|
};
|
|
|
|
U_BOOT_CRYPTO_ALGO(rsa4096) = {
|
|
.name = "rsa4096",
|
|
.key_len = RSA4096_BYTES,
|
|
.verify = rsa_verify,
|
|
};
|
|
|
|
#endif
|