1 files changed, 125 insertions, 8 deletions

diff --git a/host/lib/util_misc.c b/host/lib/util_misc.c
index 09df8eef..d2c21f52 100644
--- a/host/lib/util_misc.c
+++ b/host/lib/util_misc.c
@@ -5,6 +5,9 @@
  * Miscellaneous functions for userspace vboot utilities.
  */
 
+#define OPENSSL_NO_SHA
+#include <openssl/rsa.h>
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -15,12 +18,126 @@
 #include "util_misc.h"
 #include "vboot_common.h"
 
-void PrintPubKeySha1Sum(VbPublicKey* key) {
-  uint8_t* buf = ((uint8_t *)key) + key->key_offset;
-  uint64_t buflen = key->key_size;
-  uint8_t* digest = DigestBuf(buf, buflen, SHA1_DIGEST_ALGORITHM);
-  int i;
-  for (i=0; i<SHA1_DIGEST_SIZE; i++)
-    printf("%02x", digest[i]);
-  free(digest);
+void PrintPubKeySha1Sum(VbPublicKey *key)
+{
+	uint8_t *buf = ((uint8_t *)key) + key->key_offset;
+	uint64_t buflen = key->key_size;
+	uint8_t *digest = DigestBuf(buf, buflen, SHA1_DIGEST_ALGORITHM);
+	int i;
+	for (i = 0; i < SHA1_DIGEST_SIZE; i++)
+		printf("%02x", digest[i]);
+	free(digest);
+}
+
+int vb_keyb_from_rsa(struct rsa_st *rsa_private_key,
+		     uint8_t **keyb_data, uint32_t *keyb_size)
+{
+	uint32_t i, nwords;
+	BIGNUM *N = NULL;
+	BIGNUM *Big1 = NULL, *Big2 = NULL, *Big32 = NULL, *BigMinus1 = NULL;
+	BIGNUM *B = NULL;
+	BIGNUM *N0inv = NULL, *R = NULL, *RR = NULL;
+	BIGNUM *RRTemp = NULL, *NnumBits = NULL;
+	BIGNUM *n = NULL, *rr = NULL;
+	BN_CTX *bn_ctx = BN_CTX_new();
+	uint32_t n0invout;
+	uint32_t bufsize;
+	uint32_t *outbuf;
+	int retval = 1;
+
+	/* Size of RSA key in 32-bit words */
+	nwords = BN_num_bits(rsa_private_key->n) / 32;
+
+	bufsize = (2 + nwords + nwords) * sizeof(uint32_t);
+	outbuf = malloc(bufsize);
+	if (!outbuf)
+		goto done;
+
+	*keyb_data = (uint8_t *)outbuf;
+	*keyb_size = bufsize;
+
+	*outbuf++ = nwords;
+
+	/* Initialize BIGNUMs */
+#define NEW_BIGNUM(x) do { x = BN_new(); if (!x) goto done; } while (0)
+	NEW_BIGNUM(N);
+	NEW_BIGNUM(Big1);
+	NEW_BIGNUM(Big2);
+	NEW_BIGNUM(Big32);
+	NEW_BIGNUM(BigMinus1);
+	NEW_BIGNUM(N0inv);
+	NEW_BIGNUM(R);
+	NEW_BIGNUM(RR);
+	NEW_BIGNUM(RRTemp);
+	NEW_BIGNUM(NnumBits);
+	NEW_BIGNUM(n);
+	NEW_BIGNUM(rr);
+	NEW_BIGNUM(B);
+#undef NEW_BIGNUM
+
+	BN_copy(N, rsa_private_key->n);
+	BN_set_word(Big1, 1L);
+	BN_set_word(Big2, 2L);
+	BN_set_word(Big32, 32L);
+	BN_sub(BigMinus1, Big1, Big2);
+
+	BN_exp(B, Big2, Big32, bn_ctx); /* B = 2^32 */
+
+	/* Calculate and output N0inv = -1 / N[0] mod 2^32 */
+	BN_mod_inverse(N0inv, N, B, bn_ctx);
+	BN_sub(N0inv, B, N0inv);
+	n0invout = BN_get_word(N0inv);
+
+	*outbuf++ = n0invout;
+
+	/* Calculate R = 2^(# of key bits) */
+	BN_set_word(NnumBits, BN_num_bits(N));
+	BN_exp(R, Big2, NnumBits, bn_ctx);
+
+	/* Calculate RR = R^2 mod N */
+	BN_copy(RR, R);
+	BN_mul(RRTemp, RR, R, bn_ctx);
+	BN_mod(RR, RRTemp, N, bn_ctx);
+
+
+	/* Write out modulus as little endian array of integers. */
+	for (i = 0; i < nwords; ++i) {
+		uint32_t nout;
+
+		BN_mod(n, N, B, bn_ctx); /* n = N mod B */
+		nout = BN_get_word(n);
+		*outbuf++ = nout;
+
+		BN_rshift(N, N, 32); /*  N = N/B */
+	}
+
+	/* Write R^2 as little endian array of integers. */
+	for (i = 0; i < nwords; ++i) {
+		uint32_t rrout;
+
+		BN_mod(rr, RR, B, bn_ctx); /* rr = RR mod B */
+		rrout = BN_get_word(rr);
+		*outbuf++ = rrout;
+
+		BN_rshift(RR, RR, 32); /* RR = RR/B */
+	}
+
+	outbuf = NULL;
+	retval = 0;
+
+done:
+	free(outbuf);
+	/* Free BIGNUMs. */
+	BN_free(Big1);
+	BN_free(Big2);
+	BN_free(Big32);
+	BN_free(BigMinus1);
+	BN_free(N0inv);
+	BN_free(R);
+	BN_free(RRTemp);
+	BN_free(NnumBits);
+	BN_free(n);
+	BN_free(rr);
+
+	return retval;
 }