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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_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_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, int pkcs_1_mgf1( int hash_idx,

76
src/pk/rsa/rsa_sign_hash.c
View File

@ -23,7 +23,7 @@
@param inlen The length of the hash to sign (octets) @param inlen The length of the hash to sign (octets)
@param out [out] The signature @param out [out] The signature
@param outlen [in/out] The max size and resulting size of 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 An active PRNG state
@param prng_idx The index of the PRNG desired @param prng_idx The index of the PRNG desired
@param hash_idx The index of the hash 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); LTC_ARGCHK(key != NULL);
/* valid padding? */ /* 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; return CRYPT_PK_INVALID_PADDING;
} }
if (padding == LTC_PKCS_1_PSS) { if (padding == LTC_PKCS_1_PSS) {
/* valid prng and hash ? */ /* valid prng ? */
if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) { if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
return err; return err;
} }
}
if (padding != LTC_PKCS_1_V1_5_NA1) {
/* valid hash ? */
if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
return err; return err;
} }
@ -81,46 +87,54 @@ int rsa_sign_hash_ex(const unsigned char *in, unsigned long inlen,
} else { } else {
/* PKCS #1 v1.5 pad the hash */ /* PKCS #1 v1.5 pad the hash */
unsigned char *tmpin; unsigned char *tmpin;
ltc_asn1_list digestinfo[2], siginfo[2];
/* not all hashes have OIDs... so sad */ if (padding == LTC_PKCS_1_V1_5) {
if (hash_descriptor[hash_idx].OIDlen == 0) { ltc_asn1_list digestinfo[2], siginfo[2];
return CRYPT_INVALID_ARG; /* not all hashes have OIDs... so sad */
} if (hash_descriptor[hash_idx].OIDlen == 0) {
return CRYPT_INVALID_ARG;
}
/* construct the SEQUENCE /* construct the SEQUENCE
SEQUENCE { SEQUENCE {
SEQUENCE {hashoid OID SEQUENCE {hashoid OID
blah NULL blah NULL
} }
hash OCTET STRING hash OCTET STRING
}
*/
LTC_SET_ASN1(digestinfo, 0, LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash_idx].OID, hash_descriptor[hash_idx].OIDlen);
LTC_SET_ASN1(digestinfo, 1, LTC_ASN1_NULL, NULL, 0);
LTC_SET_ASN1(siginfo, 0, LTC_ASN1_SEQUENCE, digestinfo, 2);
LTC_SET_ASN1(siginfo, 1, LTC_ASN1_OCTET_STRING, in, inlen);
/* allocate memory for the encoding */
y = mp_unsigned_bin_size(key->N);
tmpin = XMALLOC(y);
if (tmpin == NULL) {
return CRYPT_MEM;
} }
*/
LTC_SET_ASN1(digestinfo, 0, LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash_idx].OID, hash_descriptor[hash_idx].OIDlen);
LTC_SET_ASN1(digestinfo, 1, LTC_ASN1_NULL, NULL, 0);
LTC_SET_ASN1(siginfo, 0, LTC_ASN1_SEQUENCE, digestinfo, 2);
LTC_SET_ASN1(siginfo, 1, LTC_ASN1_OCTET_STRING, in, inlen);
/* allocate memory for the encoding */ if ((err = der_encode_sequence(siginfo, 2, tmpin, &y)) != CRYPT_OK) {
y = mp_unsigned_bin_size(key->N); XFREE(tmpin);
tmpin = XMALLOC(y); return err;
if (tmpin == NULL) { }
return CRYPT_MEM; } else {
} /* set the pointer and data-length to the input values */
tmpin = (unsigned char *)in;
if ((err = der_encode_sequence(siginfo, 2, tmpin, &y)) != CRYPT_OK) { y = inlen;
XFREE(tmpin);
return err;
} }
x = *outlen; x = *outlen;
if ((err = pkcs_1_v1_5_encode(tmpin, y, LTC_PKCS_1_EMSA, err = pkcs_1_v1_5_encode(tmpin, y, LTC_PKCS_1_EMSA, modulus_bitlen, NULL, 0, out, &x);
modulus_bitlen, NULL, 0,
out, &x)) != CRYPT_OK) { if (padding == LTC_PKCS_1_V1_5) {
XFREE(tmpin); XFREE(tmpin);
}
if (err != CRYPT_OK) {
return err; return err;
} }
XFREE(tmpin);
} }
/* RSA encode it */ /* RSA encode it */

83
src/pk/rsa/rsa_verify_hash.c
View File

@ -23,7 +23,7 @@
@param siglen The length of the signature data (octets) @param siglen The length of the signature data (octets)
@param hash The hash of the message that was signed @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 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 hash_idx The index of the desired hash
@param saltlen The length of the salt used during signature @param saltlen The length of the salt used during signature
@param stat [out] The result of the signature comparison, 1==valid, 0==invalid @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? */ /* valid padding? */
if ((padding != LTC_PKCS_1_V1_5) && 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; return CRYPT_PK_INVALID_PADDING;
} }
if (padding == LTC_PKCS_1_PSS) { if (padding != LTC_PKCS_1_V1_5_NA1) {
/* valid hash ? */ /* valid hash ? */
if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
return err; return err;
@ -103,15 +104,8 @@ int rsa_verify_hash_ex(const unsigned char *sig, unsigned long siglen,
} else { } else {
/* PKCS #1 v1.5 decode it */ /* PKCS #1 v1.5 decode it */
unsigned char *out; unsigned char *out;
unsigned long outlen, loid[16], reallen; unsigned long outlen;
int decoded; 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 */ /* allocate temp buffer for decoded hash */
outlen = ((modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0)) - 3; outlen = ((modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0)) - 3;
@ -126,37 +120,54 @@ int rsa_verify_hash_ex(const unsigned char *sig, unsigned long siglen,
goto bail_2; goto bail_2;
} }
/* now we must decode out[0...outlen-1] using ASN.1, test the OID and then test the hash */ if (padding == LTC_PKCS_1_V1_5) {
/* construct the SEQUENCE unsigned long loid[16], reallen;
SEQUENCE { ltc_asn1_list digestinfo[2], siginfo[2];
SEQUENCE {hashoid OID
blah NULL /* not all hashes have OIDs... so sad */
} if (hash_descriptor[hash_idx].OIDlen == 0) {
hash OCTET STRING err = CRYPT_INVALID_ARG;
goto bail_2;
} }
*/
LTC_SET_ASN1(digestinfo, 0, LTC_ASN1_OBJECT_IDENTIFIER, loid, sizeof(loid)/sizeof(loid[0]));
LTC_SET_ASN1(digestinfo, 1, LTC_ASN1_NULL, NULL, 0);
LTC_SET_ASN1(siginfo, 0, LTC_ASN1_SEQUENCE, digestinfo, 2);
LTC_SET_ASN1(siginfo, 1, LTC_ASN1_OCTET_STRING, tmpbuf, siglen);
if ((err = der_decode_sequence(out, outlen, siginfo, 2)) != CRYPT_OK) { /* now we must decode out[0...outlen-1] using ASN.1, test the OID and then test the hash */
XFREE(out); /* construct the SEQUENCE
goto bail_2; SEQUENCE {
} SEQUENCE {hashoid OID
blah NULL
}
hash OCTET STRING
}
*/
LTC_SET_ASN1(digestinfo, 0, LTC_ASN1_OBJECT_IDENTIFIER, loid, sizeof(loid)/sizeof(loid[0]));
LTC_SET_ASN1(digestinfo, 1, LTC_ASN1_NULL, NULL, 0);
LTC_SET_ASN1(siginfo, 0, LTC_ASN1_SEQUENCE, digestinfo, 2);
LTC_SET_ASN1(siginfo, 1, LTC_ASN1_OCTET_STRING, tmpbuf, siglen);
if ((err = der_length_sequence(siginfo, 2, &reallen)) != CRYPT_OK) { if ((err = der_decode_sequence(out, outlen, siginfo, 2)) != CRYPT_OK) {
XFREE(out); XFREE(out);
goto bail_2; goto bail_2;
} }
/* test OID */ if ((err = der_length_sequence(siginfo, 2, &reallen)) != CRYPT_OK) {
if ((reallen == outlen) && XFREE(out);
(digestinfo[0].size == hash_descriptor[hash_idx].OIDlen) && goto bail_2;
}
/* test OID */
if ((reallen == outlen) &&
(digestinfo[0].size == hash_descriptor[hash_idx].OIDlen) &&
(XMEM_NEQ(digestinfo[0].data, hash_descriptor[hash_idx].OID, sizeof(unsigned long) * hash_descriptor[hash_idx].OIDlen) == 0) && (XMEM_NEQ(digestinfo[0].data, hash_descriptor[hash_idx].OID, sizeof(unsigned long) * hash_descriptor[hash_idx].OIDlen) == 0) &&
(siginfo[1].size == hashlen) && (siginfo[1].size == hashlen) &&
(XMEM_NEQ(siginfo[1].data, hash, hashlen) == 0)) { (XMEM_NEQ(siginfo[1].data, hash, hashlen) == 0)) {
*stat = 1; *stat = 1;
}
} else {
/* only check if the hash is equal */
if ((hashlen == outlen) &&
(XMEMCMP(out, hash, hashlen) == 0)) {
*stat = 1;
}
} }
#ifdef LTC_CLEAN_STACK #ifdef LTC_CLEAN_STACK