pd.if.org Git - zpackage/blob - libtomcrypt/src/pk/dsa/dsa_import.c

   1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
   2  *
   3  * LibTomCrypt is a library that provides various cryptographic
   4  * algorithms in a highly modular and flexible manner.
   5  *
   6  * The library is free for all purposes without any express
   7  * guarantee it works.
   8  */
   9 #include "tomcrypt.h"
  10
  11 /**
  12    @file dsa_import.c
  13    DSA implementation, import a DSA key, Tom St Denis
  14 */
  15
  16 #ifdef LTC_MDSA
  17
  18 /**
  19    Import a DSA key
  20    @param in       The binary packet to import from
  21    @param inlen    The length of the binary packet
  22    @param key      [out] Where to store the imported key
  23    @return CRYPT_OK if successful, upon error this function will free all allocated memory
  24 */
  25 int dsa_import(const unsigned char *in, unsigned long inlen, dsa_key *key)
  26 {
  27    int           err, stat;
  28    unsigned long zero = 0;
  29    unsigned char* tmpbuf = NULL;
  30    unsigned char flags[1];
  31
  32    LTC_ARGCHK(in  != NULL);
  33    LTC_ARGCHK(key != NULL);
  34    LTC_ARGCHK(ltc_mp.name != NULL);
  35
  36    /* init key */
  37    if (mp_init_multi(&key->p, &key->g, &key->q, &key->x, &key->y, NULL) != CRYPT_OK) {
  38       return CRYPT_MEM;
  39    }
  40
  41    /* try to match the old libtomcrypt format */
  42    err = der_decode_sequence_multi(in, inlen, LTC_ASN1_BIT_STRING, 1UL, flags,
  43                                               LTC_ASN1_EOL,        0UL, NULL);
  44
  45    if (err == CRYPT_OK || err == CRYPT_INPUT_TOO_LONG) {
  46        /* private key */
  47        if (flags[0] == 1) {
  48            if ((err = der_decode_sequence_multi(in, inlen,
  49                                   LTC_ASN1_BIT_STRING,   1UL, flags,
  50                                   LTC_ASN1_INTEGER,      1UL, key->g,
  51                                   LTC_ASN1_INTEGER,      1UL, key->p,
  52                                   LTC_ASN1_INTEGER,      1UL, key->q,
  53                                   LTC_ASN1_INTEGER,      1UL, key->y,
  54                                   LTC_ASN1_INTEGER,      1UL, key->x,
  55                                   LTC_ASN1_EOL,          0UL, NULL)) != CRYPT_OK) {
  56                goto LBL_ERR;
  57            }
  58            key->type = PK_PRIVATE;
  59            goto LBL_OK;
  60        }
  61        /* public key */
  62        else if (flags[0] == 0) {
  63            if ((err = der_decode_sequence_multi(in, inlen,
  64                                       LTC_ASN1_BIT_STRING,   1UL, flags,
  65                                       LTC_ASN1_INTEGER,      1UL, key->g,
  66                                       LTC_ASN1_INTEGER,      1UL, key->p,
  67                                       LTC_ASN1_INTEGER,      1UL, key->q,
  68                                       LTC_ASN1_INTEGER,      1UL, key->y,
  69                                       LTC_ASN1_EOL,          0UL, NULL)) != CRYPT_OK) {
  70                goto LBL_ERR;
  71            }
  72            key->type = PK_PUBLIC;
  73            goto LBL_OK;
  74        }
  75        else {
  76           err = CRYPT_INVALID_PACKET;
  77           goto LBL_ERR;
  78        }
  79    }
  80    /* get key type */
  81    if ((err = der_decode_sequence_multi(in, inlen,
  82                           LTC_ASN1_SHORT_INTEGER, 1UL, &zero,
  83                           LTC_ASN1_INTEGER,      1UL, key->p,
  84                           LTC_ASN1_INTEGER,      1UL, key->q,
  85                           LTC_ASN1_INTEGER,      1UL, key->g,
  86                           LTC_ASN1_INTEGER,      1UL, key->y,
  87                           LTC_ASN1_INTEGER,      1UL, key->x,
  88                           LTC_ASN1_EOL,          0UL, NULL)) == CRYPT_OK) {
  89
  90        key->type = PK_PRIVATE;
  91    } else { /* public */
  92       ltc_asn1_list params[3];
  93       unsigned long tmpbuf_len = inlen;
  94
  95       LTC_SET_ASN1(params, 0, LTC_ASN1_INTEGER, key->p, 1UL);
  96       LTC_SET_ASN1(params, 1, LTC_ASN1_INTEGER, key->q, 1UL);
  97       LTC_SET_ASN1(params, 2, LTC_ASN1_INTEGER, key->g, 1UL);
  98
  99       tmpbuf = XCALLOC(1, tmpbuf_len);
 100       if (tmpbuf == NULL) {
 101          err = CRYPT_MEM;
 102          goto LBL_ERR;
 103       }
 104
 105       err = der_decode_subject_public_key_info(in, inlen, PKA_DSA,
 106                                                tmpbuf, &tmpbuf_len,
 107                                                LTC_ASN1_SEQUENCE, params, 3);
 108       if (err != CRYPT_OK) {
 109          XFREE(tmpbuf);
 110          goto LBL_ERR;
 111       }
 112
 113       if ((err=der_decode_integer(tmpbuf, tmpbuf_len, key->y)) != CRYPT_OK) {
 114          XFREE(tmpbuf);
 115          goto LBL_ERR;
 116       }
 117
 118       XFREE(tmpbuf);
 119       key->type = PK_PUBLIC;
 120    }
 121
 122 LBL_OK:
 123    key->qord = mp_unsigned_bin_size(key->q);
 124
 125    /* quick p, q, g validation, without primality testing */
 126    if ((err = dsa_int_validate_pqg(key, &stat)) != CRYPT_OK) {
 127       goto LBL_ERR;
 128    }
 129    if (stat == 0) {
 130       err = CRYPT_INVALID_PACKET;
 131       goto LBL_ERR;
 132    }
 133    /* validate x, y */
 134    if ((err = dsa_int_validate_xy(key, &stat)) != CRYPT_OK) {
 135       goto LBL_ERR;
 136    }
 137    if (stat == 0) {
 138       err = CRYPT_INVALID_PACKET;
 139       goto LBL_ERR;
 140    }
 141
 142   return CRYPT_OK;
 143 LBL_ERR:
 144    dsa_free(key);
 145    return err;
 146 }
 147
 148 #endif
 149
 150 /* ref:         $Format:%D$ */
 151 /* git commit:  $Format:%H$ */
 152 /* commit time: $Format:%ai$ */