security/nss/lib/freebl/alghmac.c

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  36
  37 #include "secport.h"
  38 #include "hasht.h"
  39 #include "blapit.h"
  40 #include "alghmac.h"
  41 #include "secerr.h"
  42
  43 #define HMAC_PAD_SIZE HASH_BLOCK_LENGTH_MAX
  44
  45 struct HMACContextStr {
  46     void *hash;
  47     const SECHashObject *hashobj;
  48     PRBool        wasAllocated;
  49     unsigned char ipad[HMAC_PAD_SIZE];
  50     unsigned char opad[HMAC_PAD_SIZE];
  51 };
  52
  53 void
  54 HMAC_Destroy(HMACContext *cx, PRBool freeit)
  55 {
  56     if (cx == NULL)
  57         return;
  58
  59     PORT_Assert(!freeit == !cx->wasAllocated);
  60     if (cx->hash != NULL) {
  61         cx->hashobj->destroy(cx->hash, PR_TRUE);
  62         PORT_Memset(cx, 0, sizeof *cx);
  63     }
  64     if (freeit)
  65         PORT_Free(cx);
  66 }
  67
  68 SECStatus
  69 HMAC_Init( HMACContext * cx, const SECHashObject *hash_obj,
  70            const unsigned char *secret, unsigned int secret_len, PRBool isFIPS)
  71 {
  72     unsigned int i;
  73     unsigned char hashed_secret[HASH_LENGTH_MAX];
  74
  75     /* required by FIPS 198 Section 3 */
  76     if (isFIPS && secret_len < hash_obj->length/2) {
  77         PORT_SetError(SEC_ERROR_INVALID_ARGS);
  78         return SECFailure;
  79     }
  80     if (cx == NULL) {
  81         PORT_SetError(SEC_ERROR_INVALID_ARGS);
  82         return SECFailure;
  83     }
  84     cx->wasAllocated = PR_FALSE;
  85     cx->hashobj = hash_obj;
  86     cx->hash = cx->hashobj->create();
  87     if (cx->hash == NULL)
  88         goto loser;
  89
  90     if (secret_len > cx->hashobj->blocklength) {
  91         cx->hashobj->begin( cx->hash);
  92         cx->hashobj->update(cx->hash, secret, secret_len);
  93         PORT_Assert(cx->hashobj->length <= sizeof hashed_secret);
  94         cx->hashobj->end(   cx->hash, hashed_secret, &secret_len,
  95                          sizeof hashed_secret);
  96         if (secret_len != cx->hashobj->length) {
  97             PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
  98             goto loser;
  99         }
 100         secret = (const unsigned char *)&hashed_secret[0];
 101     }
 102
 103     PORT_Memset(cx->ipad, 0x36, cx->hashobj->blocklength);
 104     PORT_Memset(cx->opad, 0x5c, cx->hashobj->blocklength);
 105
 106     /* fold secret into padding */
 107     for (i = 0; i < secret_len; i++) {
 108         cx->ipad[i] ^= secret[i];
 109         cx->opad[i] ^= secret[i];
 110     }
 111     PORT_Memset(hashed_secret, 0, sizeof hashed_secret);
 112     return SECSuccess;
 113
 114 loser:
 115     PORT_Memset(hashed_secret, 0, sizeof hashed_secret);
 116     if (cx->hash != NULL)
 117         cx->hashobj->destroy(cx->hash, PR_TRUE);
 118     return SECFailure;
 119 }
 120
 121 HMACContext *
 122 HMAC_Create(const SECHashObject *hash_obj, const unsigned char *secret,
 123             unsigned int secret_len, PRBool isFIPS)
 124 {
 125     SECStatus rv;
 126     HMACContext * cx = PORT_ZNew(HMACContext);
 127     if (cx == NULL)
 128         return NULL;
 129     rv = HMAC_Init(cx, hash_obj, secret, secret_len, isFIPS);
 130     cx->wasAllocated = PR_TRUE;
 131     if (rv != SECSuccess) {
 132         PORT_Free(cx); /* contains no secret info */
 133         cx = NULL;
 134     }
 135     return cx;
 136 }
 137
 138 void
 139 HMAC_Begin(HMACContext *cx)
 140 {
 141     /* start inner hash */
 142     cx->hashobj->begin(cx->hash);
 143     cx->hashobj->update(cx->hash, cx->ipad, cx->hashobj->blocklength);
 144 }
 145
 146 void
 147 HMAC_Update(HMACContext *cx, const unsigned char *data, unsigned int data_len)
 148 {
 149     cx->hashobj->update(cx->hash, data, data_len);
 150 }
 151
 152 SECStatus
 153 HMAC_Finish(HMACContext *cx, unsigned char *result, unsigned int *result_len,
 154             unsigned int max_result_len)
 155 {
 156     if (max_result_len < cx->hashobj->length) {
 157         PORT_SetError(SEC_ERROR_INVALID_ARGS);
 158         return SECFailure;
 159     }
 160
 161     cx->hashobj->end(cx->hash, result, result_len, max_result_len);
 162     if (*result_len != cx->hashobj->length)
 163         return SECFailure;
 164
 165     cx->hashobj->begin(cx->hash);
 166     cx->hashobj->update(cx->hash, cx->opad, cx->hashobj->blocklength);
 167     cx->hashobj->update(cx->hash, result, *result_len);
 168     cx->hashobj->end(cx->hash, result, result_len, max_result_len);
 169     return SECSuccess;
 170 }
 171
 172 HMACContext *
 173 HMAC_Clone(HMACContext *cx)
 174 {
 175     HMACContext *newcx;
 176
 177     newcx = (HMACContext*)PORT_ZAlloc(sizeof(HMACContext));
 178     if (newcx == NULL)
 179         goto loser;
 180
 181     newcx->wasAllocated = PR_TRUE;
 182     newcx->hashobj = cx->hashobj;
 183     newcx->hash = cx->hashobj->clone(cx->hash);
 184     if (newcx->hash == NULL)
 185         goto loser;
 186     PORT_Memcpy(newcx->ipad, cx->ipad, cx->hashobj->blocklength);
 187     PORT_Memcpy(newcx->opad, cx->opad, cx->hashobj->blocklength);
 188     return newcx;
 189
 190 loser:
 191     HMAC_Destroy(newcx, PR_TRUE);
 192     return NULL;
 193 }