1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10 #include "tomcrypt_private.h"
11
12 /**
13 @file rsa_sign_hash.c
14 RSA PKCS #1 v1.5 and v2 PSS sign hash, Tom St Denis and Andreas Lange
15 */
16
17 #ifdef LTC_MRSA
18
19 /**
20 PKCS #1 pad then sign
21 @param in The hash to sign
22 @param inlen The length of the hash to sign (octets)
23 @param out [out] The signature
24 @param outlen [in/out] The max size and resulting size of the signature
25 @param padding Type of padding (LTC_PKCS_1_PSS, LTC_PKCS_1_V1_5 or LTC_PKCS_1_V1_5_NA1)
26 @param prng An active PRNG state
27 @param prng_idx The index of the PRNG desired
28 @param hash_idx The index of the hash desired
29 @param saltlen The length of the salt desired (octets)
30 @param key The private RSA key to use
31 @return CRYPT_OK if successful
32 */
rsa_sign_hash_ex(const unsigned char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen,int padding,prng_state * prng,int prng_idx,int hash_idx,unsigned long saltlen,const rsa_key * key)33 int rsa_sign_hash_ex(const unsigned char *in, unsigned long inlen,
34 unsigned char *out, unsigned long *outlen,
35 int padding,
36 prng_state *prng, int prng_idx,
37 int hash_idx, unsigned long saltlen,
38 const rsa_key *key)
39 {
40 unsigned long modulus_bitlen, modulus_bytelen, x, y;
41 int err;
42
43 LTC_ARGCHK(in != NULL);
44 LTC_ARGCHK(out != NULL);
45 LTC_ARGCHK(outlen != NULL);
46 LTC_ARGCHK(key != NULL);
47
48 /* valid padding? */
49 if ((padding != LTC_PKCS_1_V1_5) &&
50 (padding != LTC_PKCS_1_PSS) &&
51 (padding != LTC_PKCS_1_V1_5_NA1)) {
52 return CRYPT_PK_INVALID_PADDING;
53 }
54
55 if (padding == LTC_PKCS_1_PSS) {
56 /* valid prng ? */
57 if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
58 return err;
59 }
60 }
61
62 if (padding != LTC_PKCS_1_V1_5_NA1) {
63 /* valid hash ? */
64 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
65 return err;
66 }
67 }
68
69 /* get modulus len in bits */
70 modulus_bitlen = mp_count_bits((key->N));
71
72 /* outlen must be at least the size of the modulus */
73 modulus_bytelen = mp_unsigned_bin_size((key->N));
74 if (modulus_bytelen > *outlen) {
75 *outlen = modulus_bytelen;
76 return CRYPT_BUFFER_OVERFLOW;
77 }
78
79 if (padding == LTC_PKCS_1_PSS) {
80 /* PSS pad the key */
81 x = *outlen;
82 if ((err = pkcs_1_pss_encode(in, inlen, saltlen, prng, prng_idx,
83 hash_idx, modulus_bitlen, out, &x)) != CRYPT_OK) {
84 return err;
85 }
86 } else {
87 /* PKCS #1 v1.5 pad the hash */
88 unsigned char *tmpin;
89
90 if (padding == LTC_PKCS_1_V1_5) {
91 ltc_asn1_list digestinfo[2], siginfo[2];
92 /* not all hashes have OIDs... so sad */
93 if (hash_descriptor[hash_idx]->OIDlen == 0) {
94 return CRYPT_INVALID_ARG;
95 }
96
97 /* construct the SEQUENCE
98 SEQUENCE {
99 SEQUENCE {hashoid OID
100 blah NULL
101 }
102 hash OCTET STRING
103 }
104 */
105 LTC_SET_ASN1(digestinfo, 0, LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash_idx]->OID, hash_descriptor[hash_idx]->OIDlen);
106 LTC_SET_ASN1(digestinfo, 1, LTC_ASN1_NULL, NULL, 0);
107 LTC_SET_ASN1(siginfo, 0, LTC_ASN1_SEQUENCE, digestinfo, 2);
108 LTC_SET_ASN1(siginfo, 1, LTC_ASN1_OCTET_STRING, in, inlen);
109
110 /* allocate memory for the encoding */
111 y = mp_unsigned_bin_size(key->N);
112 tmpin = XMALLOC(y);
113 if (tmpin == NULL) {
114 return CRYPT_MEM;
115 }
116
117 if ((err = der_encode_sequence(siginfo, 2, tmpin, &y)) != CRYPT_OK) {
118 XFREE(tmpin);
119 return err;
120 }
121 } else {
122 /* set the pointer and data-length to the input values */
123 tmpin = (unsigned char *)in;
124 y = inlen;
125 }
126
127 x = *outlen;
128 err = pkcs_1_v1_5_encode(tmpin, y, LTC_PKCS_1_EMSA, modulus_bitlen, NULL, 0, out, &x);
129
130 if (padding == LTC_PKCS_1_V1_5) {
131 XFREE(tmpin);
132 }
133
134 if (err != CRYPT_OK) {
135 return err;
136 }
137 }
138
139 /* RSA encode it */
140 return ltc_mp.rsa_me(out, x, out, outlen, PK_PRIVATE, key);
141 }
142
143 #endif /* LTC_MRSA */
144
145 /* ref: $Format:%D$ */
146 /* git commit: $Format:%H$ */
147 /* commit time: $Format:%ai$ */
148