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add option to do PKCS#1 v1.5 EMSA without ASN.1 around hash

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Somehow someone forgot to add the OID in the signature field
of a SERVER_KEY_EXCHANGE message in early versions of the SSL protocol.
Therefore provide an option to be able to sign/verify a message
in that format.
This commit is contained in:
Steffen Jaeckel 2017-03-01 17:51:04 +01:00 committed by Karel Miko
parent 25878ed632
commit aa4bae5ae9
3 changed files with 94 additions and 68 deletions
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3
src/headers/tomcrypt_pkcs.h
View File

@ -13,7 +13,8 @@ enum ltc_pkcs_1_paddings
{
LTC_PKCS_1_V1_5 = 1, /* PKCS #1 v1.5 padding (\sa ltc_pkcs_1_v1_5_blocks) */
LTC_PKCS_1_OAEP = 2, /* PKCS #1 v2.0 encryption padding */
LTC_PKCS_1_PSS = 3 /* PKCS #1 v2.1 signature padding */
LTC_PKCS_1_PSS = 3, /* PKCS #1 v2.1 signature padding */
LTC_PKCS_1_V1_5_NA1 = 4 /* PKCS #1 v1.5 padding - No ASN.1 (\sa ltc_pkcs_1_v1_5_blocks) */
};
int pkcs_1_mgf1( int hash_idx,

30
src/pk/rsa/rsa_sign_hash.c
View File

@ -23,7 +23,7 @@
@param inlen The length of the hash to sign (octets)
@param out [out] The signature
@param outlen [in/out] The max size and resulting size of the signature
@param padding Type of padding (LTC_PKCS_1_PSS or LTC_PKCS_1_V1_5)
@param padding Type of padding (LTC_PKCS_1_PSS, LTC_PKCS_1_V1_5 or LTC_PKCS_1_V1_5_NA1)
@param prng An active PRNG state
@param prng_idx The index of the PRNG desired
@param hash_idx The index of the hash desired
@ -47,15 +47,21 @@ int rsa_sign_hash_ex(const unsigned char *in, unsigned long inlen,
LTC_ARGCHK(key != NULL);
/* valid padding? */
if ((padding != LTC_PKCS_1_V1_5) && (padding != LTC_PKCS_1_PSS)) {
if ((padding != LTC_PKCS_1_V1_5) &&
(padding != LTC_PKCS_1_PSS) &&
(padding != LTC_PKCS_1_V1_5_NA1)) {
return CRYPT_PK_INVALID_PADDING;
}
if (padding == LTC_PKCS_1_PSS) {
/* valid prng and hash ? */
/* valid prng ? */
if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
return err;
}
}
if (padding != LTC_PKCS_1_V1_5_NA1) {
/* valid hash ? */
if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
return err;
}
@ -81,8 +87,9 @@ int rsa_sign_hash_ex(const unsigned char *in, unsigned long inlen,
} else {
/* PKCS #1 v1.5 pad the hash */
unsigned char *tmpin;
ltc_asn1_list digestinfo[2], siginfo[2];
if (padding == LTC_PKCS_1_V1_5) {
ltc_asn1_list digestinfo[2], siginfo[2];
/* not all hashes have OIDs... so sad */
if (hash_descriptor[hash_idx].OIDlen == 0) {
return CRYPT_INVALID_ARG;
@ -112,15 +119,22 @@ int rsa_sign_hash_ex(const unsigned char *in, unsigned long inlen,
XFREE(tmpin);
return err;
}
} else {
/* set the pointer and data-length to the input values */
tmpin = (unsigned char *)in;
y = inlen;
}
x = *outlen;
if ((err = pkcs_1_v1_5_encode(tmpin, y, LTC_PKCS_1_EMSA,
modulus_bitlen, NULL, 0,
out, &x)) != CRYPT_OK) {
err = pkcs_1_v1_5_encode(tmpin, y, LTC_PKCS_1_EMSA, modulus_bitlen, NULL, 0, out, &x);
if (padding == LTC_PKCS_1_V1_5) {
XFREE(tmpin);
}
if (err != CRYPT_OK) {
return err;
}
XFREE(tmpin);
}
/* RSA encode it */

33
src/pk/rsa/rsa_verify_hash.c
View File

@ -23,7 +23,7 @@
@param siglen The length of the signature data (octets)
@param hash The hash of the message that was signed
@param hashlen The length of the hash of the message that was signed (octets)
@param padding Type of padding (LTC_PKCS_1_PSS or LTC_PKCS_1_V1_5)
@param padding Type of padding (LTC_PKCS_1_PSS, LTC_PKCS_1_V1_5 or LTC_PKCS_1_V1_5_NA1)
@param hash_idx The index of the desired hash
@param saltlen The length of the salt used during signature
@param stat [out] The result of the signature comparison, 1==valid, 0==invalid
@ -51,11 +51,12 @@ int rsa_verify_hash_ex(const unsigned char *sig, unsigned long siglen,
/* valid padding? */
if ((padding != LTC_PKCS_1_V1_5) &&
(padding != LTC_PKCS_1_PSS)) {
(padding != LTC_PKCS_1_PSS) &&
(padding != LTC_PKCS_1_V1_5_NA1)) {
return CRYPT_PK_INVALID_PADDING;
}
if (padding == LTC_PKCS_1_PSS) {
if (padding != LTC_PKCS_1_V1_5_NA1) {
/* valid hash ? */
if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
return err;
@ -103,15 +104,8 @@ int rsa_verify_hash_ex(const unsigned char *sig, unsigned long siglen,
} else {
/* PKCS #1 v1.5 decode it */
unsigned char *out;
unsigned long outlen, loid[16], reallen;
unsigned long outlen;
int decoded;
ltc_asn1_list digestinfo[2], siginfo[2];
/* not all hashes have OIDs... so sad */
if (hash_descriptor[hash_idx].OIDlen == 0) {
err = CRYPT_INVALID_ARG;
goto bail_2;
}
/* allocate temp buffer for decoded hash */
outlen = ((modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0)) - 3;
@ -126,6 +120,16 @@ int rsa_verify_hash_ex(const unsigned char *sig, unsigned long siglen,
goto bail_2;
}
if (padding == LTC_PKCS_1_V1_5) {
unsigned long loid[16], reallen;
ltc_asn1_list digestinfo[2], siginfo[2];
/* not all hashes have OIDs... so sad */
if (hash_descriptor[hash_idx].OIDlen == 0) {
err = CRYPT_INVALID_ARG;
goto bail_2;
}
/* now we must decode out[0...outlen-1] using ASN.1, test the OID and then test the hash */
/* construct the SEQUENCE
SEQUENCE {
@ -158,6 +162,13 @@ int rsa_verify_hash_ex(const unsigned char *sig, unsigned long siglen,
(XMEM_NEQ(siginfo[1].data, hash, hashlen) == 0)) {
*stat = 1;
}
} else {
/* only check if the hash is equal */
if ((hashlen == outlen) &&
(XMEMCMP(out, hash, hashlen) == 0)) {
*stat = 1;
}
}
#ifdef LTC_CLEAN_STACK
zeromem(out, outlen);