summaryrefslogtreecommitdiff
path: root/libmincrypt/rsa.c
diff options
context:
space:
mode:
Diffstat (limited to 'libmincrypt/rsa.c')
-rw-r--r--libmincrypt/rsa.c188
1 files changed, 22 insertions, 166 deletions
diff --git a/libmincrypt/rsa.c b/libmincrypt/rsa.c
index d7124fb65..b4ee6af60 100644
--- a/libmincrypt/rsa.c
+++ b/libmincrypt/rsa.c
@@ -1,6 +1,6 @@
/* rsa.c
**
-** Copyright 2008, The Android Open Source Project
+** Copyright 2012, The Android Open Source Project
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are met:
@@ -13,186 +13,42 @@
** be used to endorse or promote products derived from this software
** without specific prior written permission.
**
-** THIS SOFTWARE IS PROVIDED BY Google Inc. ``AS IS'' AND ANY EXPRESS OR
+** THIS SOFTWARE IS PROVIDED BY Google Inc. ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
** EVENT SHALL Google Inc. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-** PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
-** OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
-** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+** PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+** OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
** OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
** ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "mincrypt/rsa.h"
-#include "mincrypt/sha.h"
-/* a[] -= mod */
-static void subM(const RSAPublicKey *key, uint32_t *a) {
- int64_t A = 0;
- int i;
- for (i = 0; i < key->len; ++i) {
- A += (uint64_t)a[i] - key->n[i];
- a[i] = (uint32_t)A;
- A >>= 32;
- }
-}
-
-/* return a[] >= mod */
-static int geM(const RSAPublicKey *key, const uint32_t *a) {
- int i;
- for (i = key->len; i;) {
- --i;
- if (a[i] < key->n[i]) return 0;
- if (a[i] > key->n[i]) return 1;
- }
- return 1; /* equal */
-}
-
-/* montgomery c[] += a * b[] / R % mod */
-static void montMulAdd(const RSAPublicKey *key,
- uint32_t* c,
- const uint32_t a,
- const uint32_t* b) {
- uint64_t A = (uint64_t)a * b[0] + c[0];
- uint32_t d0 = (uint32_t)A * key->n0inv;
- uint64_t B = (uint64_t)d0 * key->n[0] + (uint32_t)A;
- int i;
-
- for (i = 1; i < key->len; ++i) {
- A = (A >> 32) + (uint64_t)a * b[i] + c[i];
- B = (B >> 32) + (uint64_t)d0 * key->n[i] + (uint32_t)A;
- c[i - 1] = (uint32_t)B;
- }
-
- A = (A >> 32) + (B >> 32);
-
- c[i - 1] = (uint32_t)A;
-
- if (A >> 32) {
- subM(key, c);
- }
-}
-
-/* montgomery c[] = a[] * b[] / R % mod */
-static void montMul(const RSAPublicKey *key,
- uint32_t* c,
- const uint32_t* a,
- const uint32_t* b) {
- int i;
- for (i = 0; i < key->len; ++i) {
- c[i] = 0;
- }
- for (i = 0; i < key->len; ++i) {
- montMulAdd(key, c, a[i], b);
- }
-}
-
-/* In-place public exponentiation.
-** Input and output big-endian byte array in inout.
-*/
-static void modpow3(const RSAPublicKey *key,
- uint8_t* inout) {
- uint32_t a[RSANUMWORDS];
- uint32_t aR[RSANUMWORDS];
- uint32_t aaR[RSANUMWORDS];
- uint32_t *aaa = aR; /* Re-use location. */
- int i;
-
- /* Convert from big endian byte array to little endian word array. */
- for (i = 0; i < key->len; ++i) {
- uint32_t tmp =
- (inout[((key->len - 1 - i) * 4) + 0] << 24) |
- (inout[((key->len - 1 - i) * 4) + 1] << 16) |
- (inout[((key->len - 1 - i) * 4) + 2] << 8) |
- (inout[((key->len - 1 - i) * 4) + 3] << 0);
- a[i] = tmp;
- }
+int RSA_e_f4_verify(const RSAPublicKey* key,
+ const uint8_t* signature,
+ const int len,
+ const uint8_t* sha);
- montMul(key, aR, a, key->rr); /* aR = a * RR / R mod M */
- montMul(key, aaR, aR, aR); /* aaR = aR * aR / R mod M */
- montMul(key, aaa, aaR, a); /* aaa = aaR * a / R mod M */
+int RSA_e_3_verify(const RSAPublicKey *key,
+ const uint8_t *signature,
+ const int len,
+ const uint8_t *sha);
- /* Make sure aaa < mod; aaa is at most 1x mod too large. */
- if (geM(key, aaa)) {
- subM(key, aaa);
- }
-
- /* Convert to bigendian byte array */
- for (i = key->len - 1; i >= 0; --i) {
- uint32_t tmp = aaa[i];
- *inout++ = tmp >> 24;
- *inout++ = tmp >> 16;
- *inout++ = tmp >> 8;
- *inout++ = tmp >> 0;
- }
-}
-
-/* Expected PKCS1.5 signature padding bytes, for a keytool RSA signature.
-** Has the 0-length optional parameter encoded in the ASN1 (as opposed to the
-** other flavor which omits the optional parameter entirely). This code does not
-** accept signatures without the optional parameter.
-*/
-static const uint8_t padding[RSANUMBYTES - SHA_DIGEST_SIZE] = {
- 0x00,0x01,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0x00,
- 0x30,0x21,0x30,0x09,0x06,0x05,0x2b,0x0e,0x03,0x02,0x1a,0x05,0x00,
- 0x04,0x14
-};
-
-/* Verify a 2048 bit RSA PKCS1.5 signature against an expected SHA-1 hash.
-** Returns 0 on failure, 1 on success.
-*/
int RSA_verify(const RSAPublicKey *key,
const uint8_t *signature,
const int len,
const uint8_t *sha) {
- uint8_t buf[RSANUMBYTES];
- int i;
-
- if (key->len != RSANUMWORDS) {
- return 0; /* Wrong key passed in. */
- }
-
- if (len != sizeof(buf)) {
- return 0; /* Wrong input length. */
- }
-
- for (i = 0; i < len; ++i) {
- buf[i] = signature[i];
- }
-
- modpow3(key, buf);
-
- /* Check pkcs1.5 padding bytes. */
- for (i = 0; i < (int) sizeof(padding); ++i) {
- if (buf[i] != padding[i]) {
+ switch (key->exponent) {
+ case 3:
+ return RSA_e_3_verify(key, signature, len, sha);
+ break;
+ case 65537:
+ return RSA_e_f4_verify(key, signature, len, sha);
+ break;
+ default:
return 0;
- }
}
-
- /* Check sha digest matches. */
- for (; i < len; ++i) {
- if (buf[i] != *sha++) {
- return 0;
- }
- }
-
- return 1;
}