diff options
Diffstat (limited to 'libmincrypt/rsa.c')
-rw-r--r-- | libmincrypt/rsa.c | 188 |
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; } |