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/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Implementation of RSA utility functions.
*/
#include "sysincludes.h"
#include "cryptolib.h"
#include "stateful_util.h"
#include "utility.h"
#include "vboot_api.h"
uint64_t RSAProcessedKeySize(uint64_t algorithm, uint64_t* out_size) {
int key_len; /* Key length in bytes. (int type matches siglen_map) */
if (algorithm < kNumAlgorithms) {
key_len = siglen_map[algorithm];
/* Total size needed by a RSAPublicKey buffer is =
* 2 * key_len bytes for the n and rr arrays
* + sizeof len + sizeof n0inv.
*/
*out_size = (2 * key_len + sizeof(uint32_t) + sizeof(uint32_t));
return 1;
}
return 0;
}
RSAPublicKey* RSAPublicKeyNew(void) {
RSAPublicKey* key = (RSAPublicKey*) VbExMalloc(sizeof(RSAPublicKey));
key->n = NULL;
key->rr = NULL;
key->len = 0;
key->algorithm = kNumAlgorithms;
return key;
}
void RSAPublicKeyFree(RSAPublicKey* key) {
if (key) {
if (key->n)
VbExFree(key->n);
if (key->rr)
VbExFree(key->rr);
VbExFree(key);
}
}
RSAPublicKey* RSAPublicKeyFromBuf(const uint8_t* buf, uint64_t len) {
RSAPublicKey* key = RSAPublicKeyNew();
MemcpyState st;
uint64_t key_len;
StatefulInit(&st, (void*)buf, len);
StatefulMemcpy(&st, &key->len, sizeof(key->len));
/* key length in bytes (avoiding possible 32-bit rollover) */
key_len = key->len;
key_len *= sizeof(uint32_t);
/* Sanity Check the key length. */
if (RSA1024NUMBYTES != key_len &&
RSA2048NUMBYTES != key_len &&
RSA4096NUMBYTES != key_len &&
RSA8192NUMBYTES != key_len) {
RSAPublicKeyFree(key);
return NULL;
}
key->n = (uint32_t*) VbExMalloc(key_len);
key->rr = (uint32_t*) VbExMalloc(key_len);
StatefulMemcpy(&st, &key->n0inv, sizeof(key->n0inv));
StatefulMemcpy(&st, key->n, key_len);
StatefulMemcpy(&st, key->rr, key_len);
if (st.overrun || st.remaining_len != 0) { /* Underrun or overrun. */
RSAPublicKeyFree(key);
return NULL;
}
return key;
}
int RSAVerifyBinary_f(const uint8_t* key_blob,
const RSAPublicKey* key,
const uint8_t* buf,
uint64_t len,
const uint8_t* sig,
unsigned int algorithm) {
RSAPublicKey* verification_key = NULL;
uint8_t* digest = NULL;
uint64_t key_size;
int sig_size;
int success;
if (algorithm >= (unsigned int)kNumAlgorithms)
return 0; /* Invalid algorithm. */
if (!RSAProcessedKeySize(algorithm, &key_size))
return 0;
sig_size = siglen_map[algorithm];
if (key_blob && !key)
verification_key = RSAPublicKeyFromBuf(key_blob, key_size);
else if (!key_blob && key)
verification_key = (RSAPublicKey*) key; /* Supress const warning. */
else
return 0; /* Both can't be NULL or non-NULL. */
/* Ensure we have a valid key. */
if (!verification_key)
return 0;
digest = DigestBuf(buf, len, algorithm);
success = RSAVerify(verification_key, sig, (uint32_t)sig_size,
(uint8_t)algorithm, digest);
VbExFree(digest);
if (!key)
RSAPublicKeyFree(verification_key); /* Only free if we allocated it. */
return success;
}
/* Version of RSAVerifyBinary_f() where instead of the raw binary blob
* of data, its digest is passed as the argument. */
int RSAVerifyBinaryWithDigest_f(const uint8_t* key_blob,
const RSAPublicKey* key,
const uint8_t* digest,
const uint8_t* sig,
unsigned int algorithm) {
RSAPublicKey* verification_key = NULL;
uint64_t key_size;
int sig_size;
int success;
if (algorithm >= (unsigned int)kNumAlgorithms)
return 0; /* Invalid algorithm. */
if (!RSAProcessedKeySize(algorithm, &key_size))
return 0;
sig_size = siglen_map[algorithm];
if (key_blob && !key)
verification_key = RSAPublicKeyFromBuf(key_blob, key_size);
else if (!key_blob && key)
verification_key = (RSAPublicKey*) key; /* Supress const warning. */
else
return 0; /* Both can't be NULL or non-NULL. */
/* Ensure we have a valid key. */
if (!verification_key)
return 0;
success = RSAVerify(verification_key, sig, (uint32_t)sig_size,
(uint8_t)algorithm, digest);
if (!key)
RSAPublicKeyFree(verification_key); /* Only free if we allocated it. */
return success;
}
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