DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (4a108e94d3e2)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif
#include "blapii.h"
#include "blapit.h"
#include "gcm.h"
#include "ctr.h"
#include "secerr.h"
#include "prtypes.h"
#include "pkcs11t.h"

#include <limits.h>

/**************************************************************************
 *          First implement the Galois hash function of GCM (gcmHash)     *
 **************************************************************************/
#define GCM_HASH_LEN_LEN 8 /* gcm hash defines lengths to be 64 bits */

typedef struct gcmHashContextStr gcmHashContext;

static SECStatus gcmHash_InitContext(gcmHashContext *hash,
				     const unsigned char *H,
				     unsigned int blocksize);
static void gcmHash_DestroyContext(gcmHashContext *ghash, PRBool freeit);
static SECStatus gcmHash_Update(gcmHashContext *ghash,
				const unsigned char *buf, unsigned int len,
				unsigned int blocksize);
static SECStatus gcmHash_Sync(gcmHashContext *ghash, unsigned int blocksize);
static SECStatus gcmHash_Final(gcmHashContext *gcm, unsigned char *outbuf,
			       unsigned int *outlen, unsigned int maxout,
			       unsigned int blocksize);
static SECStatus gcmHash_Reset(gcmHashContext *ghash,
			       const unsigned char *inbuf,
			       unsigned int inbufLen, unsigned int blocksize);

/* compile time defines to select how the GF2 multiply is calculated.
 * There are currently 2 algorithms implemented here: MPI and ALGORITHM_1.
 *
 * MPI uses the GF2m implemented in mpi to support GF2 ECC.
 * ALGORITHM_1 is the Algorithm 1 in both NIST SP 800-38D and
 * "The Galois/Counter Mode of Operation (GCM)", McGrew & Viega.
 */
#if !defined(GCM_USE_ALGORITHM_1) && !defined(GCM_USE_MPI)
#define GCM_USE_MPI 1 /* MPI is about 5x faster with the
		       * same or less complexity. It's possible to use
		       * tables to speed things up even more */
#endif

/* GCM defines the bit string to be LSB first, which is exactly
 * opposite everyone else, including hardware. build array
 * to reverse everything. */
static const unsigned char gcm_byte_rev[256] = {
    0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
    0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
    0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
    0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
    0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
    0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
    0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
    0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
    0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
    0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
    0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
    0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
    0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
    0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
    0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
    0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
    0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
    0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
    0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
    0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
    0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
    0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
    0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
    0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
    0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
    0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
    0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
    0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
    0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
    0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
    0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
    0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
};


#ifdef GCM_TRACE
#include <stdio.h>

#define GCM_TRACE_X(ghash,label) { \
	unsigned char _X[MAX_BLOCK_SIZE]; int i; \
	gcm_getX(ghash, _X, blocksize); \
	printf(label,(ghash)->m); \
	for (i=0; i < blocksize; i++) printf("%02x",_X[i]); \
	printf("\n"); }
#define GCM_TRACE_BLOCK(label,buf,blocksize) {\
	printf(label); \
	for (i=0; i < blocksize; i++) printf("%02x",buf[i]); \
	printf("\n"); }
#else
#define GCM_TRACE_X(ghash,label)
#define GCM_TRACE_BLOCK(label,buf,blocksize)
#endif

#ifdef GCM_USE_MPI

#ifdef GCM_USE_ALGORITHM_1
#error "Only define one of GCM_USE_MPI, GCM_USE_ALGORITHM_1"
#endif
/* use the MPI functions to calculate Xn = (Xn-1^C_i)*H mod poly */
#include "mpi.h"
#include "secmpi.h"
#include "mplogic.h"
#include "mp_gf2m.h"

/* state needed to handle GCM Hash function */
struct gcmHashContextStr {
     mp_int H;
     mp_int X;
     mp_int C_i;
     const unsigned int *poly;
     unsigned char buffer[MAX_BLOCK_SIZE];
     unsigned int bufLen;
     int m; /* XXX what is m? */
     unsigned char counterBuf[2*GCM_HASH_LEN_LEN];
     PRUint64 cLen;
};

/* f = x^128 + x^7 + x^2 + x + 1 */
static const unsigned int poly_128[] = { 128, 7, 2, 1, 0 };

/* sigh, GCM defines the bit strings exactly backwards from everything else */
static void
gcm_reverse(unsigned char *target, const unsigned char *src,
							unsigned int blocksize)
{
    unsigned int i;
    for (i=0; i < blocksize; i++) {
	target[blocksize-i-1] = gcm_byte_rev[src[i]];
    }
}

/* Initialize a gcmHashContext */
static SECStatus
gcmHash_InitContext(gcmHashContext *ghash, const unsigned char *H,
		    unsigned int blocksize)
{
    mp_err err = MP_OKAY;
    unsigned char H_rev[MAX_BLOCK_SIZE];

    MP_DIGITS(&ghash->H) = 0;
    MP_DIGITS(&ghash->X) = 0;
    MP_DIGITS(&ghash->C_i) = 0;
    CHECK_MPI_OK( mp_init(&ghash->H) );
    CHECK_MPI_OK( mp_init(&ghash->X) );
    CHECK_MPI_OK( mp_init(&ghash->C_i) );

    mp_zero(&ghash->X);
    gcm_reverse(H_rev, H, blocksize);
    CHECK_MPI_OK( mp_read_unsigned_octets(&ghash->H, H_rev, blocksize) );

    /* set the irreducible polynomial. Each blocksize has its own polynomial.
     * for now only blocksize 16 (=128 bits) is defined */
    switch (blocksize) {
    case 16: /* 128 bits */
	ghash->poly = poly_128;
	break;
    default:
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	goto cleanup;
    }
    ghash->cLen = 0;
    ghash->bufLen = 0;
    ghash->m = 0;
    PORT_Memset(ghash->counterBuf, 0, sizeof(ghash->counterBuf));
    return SECSuccess;
cleanup:
    gcmHash_DestroyContext(ghash, PR_FALSE);
    return SECFailure;
}

/* Destroy a HashContext (Note we zero the digits so this function
 * is idempotent if called with freeit == PR_FALSE */
static void
gcmHash_DestroyContext(gcmHashContext *ghash, PRBool freeit)
{
    mp_clear(&ghash->H);
    mp_clear(&ghash->X);
    mp_clear(&ghash->C_i);
    MP_DIGITS(&ghash->H) = 0;
    MP_DIGITS(&ghash->X) = 0;
    MP_DIGITS(&ghash->C_i) = 0;
    if (freeit) {
	PORT_Free(ghash);
    }
}

static SECStatus
gcm_getX(gcmHashContext *ghash, unsigned char *T, unsigned int blocksize)
{
    int len;
    mp_err err;
    unsigned char tmp_buf[MAX_BLOCK_SIZE];
    unsigned char *X;

    len = mp_unsigned_octet_size(&ghash->X);
    if (len <= 0) {
	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
	return SECFailure;
    }
    X = tmp_buf;
    PORT_Assert((unsigned int)len <= blocksize);
    if ((unsigned int)len > blocksize) {
	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
	return SECFailure;
    }
    /* zero pad the result */
    if (len != blocksize) {
	PORT_Memset(X,0,blocksize-len);
	X += blocksize-len;
    }

    err = mp_to_unsigned_octets(&ghash->X, X, len);
    if (err < 0) {
	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
	return SECFailure;
    }
    gcm_reverse(T, tmp_buf, blocksize);
    return SECSuccess;
}

static SECStatus
gcm_HashMult(gcmHashContext *ghash, const unsigned char *buf,
		unsigned int count, unsigned int blocksize)
{
    SECStatus rv = SECFailure;
    mp_err err = MP_OKAY;
    unsigned char tmp_buf[MAX_BLOCK_SIZE];
    unsigned int i;

    for (i=0; i < count; i++, buf += blocksize) {
	ghash->m++;
	gcm_reverse(tmp_buf, buf, blocksize);
	CHECK_MPI_OK(mp_read_unsigned_octets(&ghash->C_i, tmp_buf, blocksize));
	CHECK_MPI_OK(mp_badd(&ghash->X, &ghash->C_i, &ghash->C_i));
	/*
	 * Looking to speed up GCM, this the the place to do it.
	 * There are two areas that can be exploited to speed up this code.
	 *
	 * 1) H is a constant in this multiply. We can precompute H * (0 - 255)
	 * at init time and this becomes an blockize xors of our table lookup.
	 *
	 * 2) poly is a constant for each blocksize. We can calculate the
	 * modulo reduction by a series of adds and shifts.
	 *
	 * For now we are after functionality, so we will go ahead and use
	 * the builtin bmulmod from mpi
	 */
        CHECK_MPI_OK(mp_bmulmod(&ghash->C_i, &ghash->H,
					ghash->poly, &ghash->X));
	GCM_TRACE_X(ghash, "X%d = ")
    }
    rv = SECSuccess;
cleanup:
    if (rv != SECSuccess) {
	MP_TO_SEC_ERROR(err);
    }
    return rv;
}

static void
gcm_zeroX(gcmHashContext *ghash)
{
    mp_zero(&ghash->X);
    ghash->m = 0;
}

#endif

#ifdef GCM_USE_ALGORITHM_1
/* use algorithm 1 of McGrew & Viega "The Galois/Counter Mode of Operation" */

#define GCM_ARRAY_SIZE (MAX_BLOCK_SIZE/sizeof(unsigned long))

struct gcmHashContextStr {
     unsigned long H[GCM_ARRAY_SIZE];
     unsigned long X[GCM_ARRAY_SIZE];
     unsigned long R;
     unsigned char buffer[MAX_BLOCK_SIZE];
     unsigned int bufLen;
     int m;
     unsigned char counterBuf[2*GCM_HASH_LEN_LEN];
     PRUint64 cLen;
};

static void
gcm_bytes_to_longs(unsigned long *l, const unsigned char *c, unsigned int len)
{
    int i,j;
    int array_size = len/sizeof(unsigned long);

    PORT_Assert(len % sizeof(unsigned long) == 0);
    for (i=0; i < array_size; i++) {
	unsigned long tmp = 0;
	int byte_offset = i * sizeof(unsigned long);
	for (j=sizeof(unsigned long)-1; j >= 0; j--) {
	    tmp = (tmp << PR_BITS_PER_BYTE) | gcm_byte_rev[c[byte_offset+j]];
	}
	l[i] = tmp;
    }
}

static void
gcm_longs_to_bytes(const unsigned long *l, unsigned char *c, unsigned int len)
{
    int i,j;
    int array_size = len/sizeof(unsigned long);

    PORT_Assert(len % sizeof(unsigned long) == 0);
    for (i=0; i < array_size; i++) {
	unsigned long tmp = l[i];
	int byte_offset = i * sizeof(unsigned long);
	for (j=0; j < sizeof(unsigned long); j++) {
	    c[byte_offset+j] = gcm_byte_rev[tmp & 0xff];
	    tmp = (tmp >> PR_BITS_PER_BYTE);
	}
    }
}


/* Initialize a gcmHashContext */
static SECStatus
gcmHash_InitContext(gcmHashContext *ghash, const unsigned char *H,
		    unsigned int blocksize)
{
    PORT_Memset(ghash->X, 0, sizeof(ghash->X));
    PORT_Memset(ghash->H, 0, sizeof(ghash->H));
    gcm_bytes_to_longs(ghash->H, H, blocksize);

    /* set the irreducible polynomial. Each blocksize has its own polynommial
     * for now only blocksize 16 (=128 bits) is defined */
    switch (blocksize) {
    case 16: /* 128 bits */
	ghash->R = (unsigned long) 0x87; /* x^7 + x^2 + x +1 */
	break;
    default:
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	goto cleanup;
    }
    ghash->cLen = 0;
    ghash->bufLen = 0;
    ghash->m = 0;
    PORT_Memset(ghash->counterBuf, 0, sizeof(ghash->counterBuf));
    return SECSuccess;
cleanup:
    return SECFailure;
}

/* Destroy a HashContext (Note we zero the digits so this function
 * is idempotent if called with freeit == PR_FALSE */
static void
gcmHash_DestroyContext(gcmHashContext *ghash, PRBool freeit)
{
    if (freeit) {
	PORT_Free(ghash);
    }
}

static unsigned long
gcm_shift_one(unsigned long *t, unsigned int count)
{
    unsigned long carry = 0;
    unsigned long nextcarry = 0;
    unsigned int i;
    for (i=0; i < count; i++) {
	nextcarry = t[i] >> ((sizeof(unsigned long)*PR_BITS_PER_BYTE)-1);
	t[i] = (t[i] << 1) | carry;
	carry = nextcarry;
    }
    return carry;
}

static SECStatus
gcm_getX(gcmHashContext *ghash, unsigned char *T, unsigned int blocksize)
{
    gcm_longs_to_bytes(ghash->X, T, blocksize);
    return SECSuccess;
}

#define GCM_XOR(t, s, len) \
	for (l=0; l < len; l++) t[l] ^= s[l]

static SECStatus
gcm_HashMult(gcmHashContext *ghash, const unsigned char *buf,
		unsigned int count, unsigned int blocksize)
{
    unsigned long C_i[GCM_ARRAY_SIZE];
    unsigned int arraysize = blocksize/sizeof(unsigned long);
    unsigned int i, j, k, l;

    for (i=0; i < count; i++, buf += blocksize) {
	ghash->m++;
	gcm_bytes_to_longs(C_i, buf, blocksize);
	GCM_XOR(C_i, ghash->X, arraysize);
	/* multiply X = C_i * H */
	PORT_Memset(ghash->X, 0, sizeof(ghash->X));
	for (j=0; j < arraysize; j++) {
	    unsigned long H = ghash->H[j];
	    for (k=0; k < sizeof(unsigned long)*PR_BITS_PER_BYTE; k++) {
		if (H & 1) {
		    GCM_XOR(ghash->X, C_i, arraysize);
		}
		if (gcm_shift_one(C_i, arraysize)) {
		    C_i[0] = C_i[0] ^ ghash->R;
		}
		H = H >> 1;
	    }
	}
	GCM_TRACE_X(ghash, "X%d = ")
    }
    return SECSuccess;
}


static void
gcm_zeroX(gcmHashContext *ghash)
{
    PORT_Memset(ghash->X, 0, sizeof(ghash->X));
    ghash->m = 0;
}
#endif

/*
 * implement GCM GHASH using the freebl GHASH function. The gcm_HashMult
 * function always takes blocksize lengths of data. gcmHash_Update will
 * format the data properly.
 */
static SECStatus
gcmHash_Update(gcmHashContext *ghash, const unsigned char *buf,
	       unsigned int len, unsigned int blocksize)
{
    unsigned int blocks;
    SECStatus rv;

    ghash->cLen += (len*PR_BITS_PER_BYTE);

    /* first deal with the current buffer of data. Try to fill it out so
     * we can hash it */
    if (ghash->bufLen) {
	unsigned int needed = PR_MIN(len, blocksize - ghash->bufLen);
	if (needed != 0) {
	    PORT_Memcpy(ghash->buffer+ghash->bufLen, buf, needed);
	}
	buf += needed;
	len -= needed;
	ghash->bufLen += needed;
	if (len == 0) {
	    /* didn't add enough to hash the data, nothing more do do */
	    return SECSuccess;
	}
	PORT_Assert(ghash->bufLen == blocksize);
	/* hash the buffer and clear it */
	rv = gcm_HashMult(ghash, ghash->buffer, 1, blocksize);
	PORT_Memset(ghash->buffer, 0, blocksize);
	ghash->bufLen = 0;
	if (rv != SECSuccess) {
	    return SECFailure;
	}
    }
    /* now hash any full blocks remaining in the data stream */
    blocks = len/blocksize;
    if (blocks) {
	rv = gcm_HashMult(ghash, buf, blocks, blocksize);
	if (rv != SECSuccess) {
	    return SECFailure;
	}
	buf += blocks*blocksize;
	len -= blocks*blocksize;
    }

    /* save any remainder in the buffer to be hashed with the next call */
    if (len != 0) {
	PORT_Memcpy(ghash->buffer, buf, len);
	ghash->bufLen = len;
    }
    return SECSuccess;
}

/*
 * write out any partial blocks zero padded through the GHASH engine,
 * save the lengths for the final completion of the hash
 */
static SECStatus
gcmHash_Sync(gcmHashContext *ghash, unsigned int blocksize)
{
    int i;
    SECStatus rv;

    /* copy the previous counter to the upper block */
    PORT_Memcpy(ghash->counterBuf, &ghash->counterBuf[GCM_HASH_LEN_LEN],
							GCM_HASH_LEN_LEN);
    /* copy the current counter in the lower block */
    for (i=0; i < GCM_HASH_LEN_LEN; i++) {
	ghash->counterBuf[GCM_HASH_LEN_LEN+i] =
	    (ghash->cLen >> ((GCM_HASH_LEN_LEN-1-i)*PR_BITS_PER_BYTE)) & 0xff;
    }
    ghash->cLen = 0;

    /* now zero fill the buffer and hash the last block */
    if (ghash->bufLen) {
	PORT_Memset(ghash->buffer+ghash->bufLen, 0, blocksize - ghash->bufLen);
	rv = gcm_HashMult(ghash, ghash->buffer, 1, blocksize);
	PORT_Memset(ghash->buffer, 0, blocksize);
	ghash->bufLen = 0;
	if (rv != SECSuccess) {
	    return SECFailure;
	}
    }
    return SECSuccess;
}

/*
 * This does the final sync, hashes the lengths, then returns
 * "T", the hashed output.
 */
static SECStatus
gcmHash_Final(gcmHashContext *ghash, unsigned char *outbuf,
		unsigned int *outlen, unsigned int maxout,
		unsigned int blocksize)
{
    unsigned char T[MAX_BLOCK_SIZE];
    SECStatus rv;

    rv = gcmHash_Sync(ghash, blocksize);
    if (rv != SECSuccess) {
	return SECFailure;
    }

    rv = gcm_HashMult(ghash, ghash->counterBuf, (GCM_HASH_LEN_LEN*2)/blocksize,
								blocksize);
    if (rv != SECSuccess) {
	return SECFailure;
    }

    GCM_TRACE_X(ghash, "GHASH(H,A,C) = ")

    rv = gcm_getX(ghash, T, blocksize);
    if (rv != SECSuccess) {
	return SECFailure;
    }

    if (maxout > blocksize) maxout = blocksize;
    PORT_Memcpy(outbuf, T, maxout);
    *outlen = maxout;
    return SECSuccess;
}

SECStatus
gcmHash_Reset(gcmHashContext *ghash, const unsigned char *AAD,
	      unsigned int AADLen, unsigned int blocksize)
{
    SECStatus rv;

    ghash->cLen = 0;
    PORT_Memset(ghash->counterBuf, 0, GCM_HASH_LEN_LEN*2);
    ghash->bufLen = 0;
    gcm_zeroX(ghash);

    /* now kick things off by hashing the Additional Authenticated Data */
    if (AADLen != 0) {
	rv = gcmHash_Update(ghash, AAD, AADLen, blocksize);
	if (rv != SECSuccess) {
	    return SECFailure;
	}
	rv = gcmHash_Sync(ghash, blocksize);
	if (rv != SECSuccess) {
	    return SECFailure;
	}
    }
    return SECSuccess;
}

/**************************************************************************
 *           Now implement the GCM using gcmHash and CTR                  *
 **************************************************************************/

/* state to handle the full GCM operation (hash and counter) */
struct GCMContextStr {
    gcmHashContext ghash_context;
    CTRContext ctr_context;
    unsigned long tagBits;
    unsigned char tagKey[MAX_BLOCK_SIZE];
};

GCMContext *
GCM_CreateContext(void *context, freeblCipherFunc cipher,
		  const unsigned char *params, unsigned int blocksize)
{
    GCMContext *gcm = NULL;
    gcmHashContext *ghash;
    unsigned char H[MAX_BLOCK_SIZE];
    unsigned int tmp;
    PRBool freeCtr = PR_FALSE;
    PRBool freeHash = PR_FALSE;
    const CK_GCM_PARAMS *gcmParams = (const CK_GCM_PARAMS *)params;
    CK_AES_CTR_PARAMS ctrParams;
    SECStatus rv;

    if (blocksize > MAX_BLOCK_SIZE || blocksize > sizeof(ctrParams.cb)) {
	PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
	return NULL;
    }
    gcm = PORT_ZNew(GCMContext);
    if (gcm == NULL) {
	return NULL;
    }
    /* first fill in the ghash context */
    ghash = &gcm->ghash_context;
    PORT_Memset(H, 0, blocksize);
    rv = (*cipher)(context, H, &tmp, blocksize, H, blocksize, blocksize);
    if (rv != SECSuccess) {
	goto loser;
    }
    rv = gcmHash_InitContext(ghash, H, blocksize);
    if (rv != SECSuccess) {
	goto loser;
    }
    freeHash = PR_TRUE;

    /* fill in the Counter context */
    ctrParams.ulCounterBits = 32;
    PORT_Memset(ctrParams.cb, 0, sizeof(ctrParams.cb));
    if ((blocksize == 16) && (gcmParams->ulIvLen == 12)) {
	PORT_Memcpy(ctrParams.cb, gcmParams->pIv, gcmParams->ulIvLen);
	ctrParams.cb[blocksize-1] = 1;
    } else {
	rv = gcmHash_Update(ghash, gcmParams->pIv, gcmParams->ulIvLen,
			    blocksize);
	if (rv != SECSuccess) {
	    goto loser;
	}
	rv = gcmHash_Final(ghash, ctrParams.cb, &tmp, blocksize, blocksize);
	if (rv != SECSuccess) {
	    goto loser;
	}
    }
    rv = CTR_InitContext(&gcm->ctr_context, context, cipher,
				(unsigned char *)&ctrParams, blocksize);
    if (rv != SECSuccess) {
	goto loser;
    }
    freeCtr = PR_TRUE;

    /* fill in the gcm structure */
    gcm->tagBits = gcmParams->ulTagBits; /* save for final step */
    /* calculate the final tag key. NOTE: gcm->tagKey is zero to start with.
     * if this assumption changes, we would need to explicitly clear it here */
    rv = CTR_Update(&gcm->ctr_context, gcm->tagKey, &tmp, blocksize,
		    gcm->tagKey, blocksize, blocksize);
    if (rv != SECSuccess) {
	goto loser;
    }

    /* finally mix in the AAD data */
    rv = gcmHash_Reset(ghash, gcmParams->pAAD, gcmParams->ulAADLen, blocksize);
    if (rv != SECSuccess) {
	goto loser;
    }

    return gcm;

loser:
    if (freeCtr) {
	CTR_DestroyContext(&gcm->ctr_context, PR_FALSE);
    }
    if (freeHash) {
	gcmHash_DestroyContext(&gcm->ghash_context, PR_FALSE);
    }
    if (gcm) {
	PORT_Free(gcm);
    }
    return NULL;
}

void
GCM_DestroyContext(GCMContext *gcm, PRBool freeit)
{
    /* these two are statically allocated and will be freed when we free
     * gcm. call their destroy functions to free up any locally
     * allocated data (like mp_int's) */
    CTR_DestroyContext(&gcm->ctr_context, PR_FALSE);
    gcmHash_DestroyContext(&gcm->ghash_context, PR_FALSE);
    if (freeit) {
	PORT_Free(gcm);
    }
}

static SECStatus
gcm_GetTag(GCMContext *gcm, unsigned char *outbuf,
	unsigned int *outlen, unsigned int maxout,
	unsigned int blocksize)
{
    unsigned int tagBytes;
    unsigned int extra;
    unsigned int i;
    SECStatus rv;

    tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;
    extra = tagBytes*PR_BITS_PER_BYTE - gcm->tagBits;

    if (outbuf == NULL) {
	*outlen = tagBytes;
	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
	return SECFailure;
    }

    if (maxout < tagBytes) {
	*outlen = tagBytes;
	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
	return SECFailure;
    }
    maxout = tagBytes;
    rv = gcmHash_Final(&gcm->ghash_context, outbuf, outlen, maxout, blocksize);
    if (rv != SECSuccess) {
	return SECFailure;
    }

    GCM_TRACE_BLOCK("GHASH=", outbuf, blocksize);
    GCM_TRACE_BLOCK("Y0=", gcm->tagKey, blocksize);
    for (i=0; i < *outlen; i++) {
	outbuf[i] ^= gcm->tagKey[i];
    }
    GCM_TRACE_BLOCK("Y0=", gcm->tagKey, blocksize);
    GCM_TRACE_BLOCK("T=", outbuf, blocksize);
    /* mask off any extra bits we got */
    if (extra) {
	outbuf[tagBytes-1] &= ~((1 << extra)-1);
    }
    return SECSuccess;
}


/*
 * See The Galois/Counter Mode of Operation, McGrew and Viega.
 *  GCM is basically counter mode with a specific initialization and
 *  built in macing operation.
 */
SECStatus
GCM_EncryptUpdate(GCMContext *gcm, unsigned char *outbuf,
		unsigned int *outlen, unsigned int maxout,
		const unsigned char *inbuf, unsigned int inlen,
		unsigned int blocksize)
{
    SECStatus rv;
    unsigned int tagBytes;
    unsigned int len;

    tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;
    if (UINT_MAX - inlen < tagBytes) {
	PORT_SetError(SEC_ERROR_INPUT_LEN);
	return SECFailure;
    }
    if (maxout < inlen + tagBytes) {
	*outlen = inlen + tagBytes;
	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
	return SECFailure;
    }

    rv = CTR_Update(&gcm->ctr_context, outbuf, outlen, maxout,
			inbuf, inlen, blocksize);
    if (rv != SECSuccess) {
	return SECFailure;
    }
    rv = gcmHash_Update(&gcm->ghash_context, outbuf, *outlen, blocksize);
    if (rv != SECSuccess) {
	PORT_Memset(outbuf, 0, *outlen); /* clear the output buffer */
	*outlen = 0;
	return SECFailure;
    }
    rv = gcm_GetTag(gcm, outbuf + *outlen, &len, maxout - *outlen, blocksize);
    if (rv != SECSuccess) {
	PORT_Memset(outbuf, 0, *outlen); /* clear the output buffer */
	*outlen = 0;
	return SECFailure;
    };
    *outlen += len;
    return SECSuccess;
}

/*
 * See The Galois/Counter Mode of Operation, McGrew and Viega.
 *  GCM is basically counter mode with a specific initialization and
 *  built in macing operation. NOTE: the only difference between Encrypt
 *  and Decrypt is when we calculate the mac. That is because the mac must
 *  always be calculated on the cipher text, not the plain text, so for
 *  encrypt, we do the CTR update first and for decrypt we do the mac first.
 */
SECStatus
GCM_DecryptUpdate(GCMContext *gcm, unsigned char *outbuf,
		unsigned int *outlen, unsigned  int maxout,
		const unsigned char *inbuf, unsigned int inlen,
		unsigned int blocksize)
{
    SECStatus rv;
    unsigned int tagBytes;
    unsigned char tag[MAX_BLOCK_SIZE];
    const unsigned char *intag;
    unsigned int len;

    tagBytes = (gcm->tagBits + (PR_BITS_PER_BYTE-1)) / PR_BITS_PER_BYTE;

    /* get the authentication block */
    if (inlen < tagBytes) {
	PORT_SetError(SEC_ERROR_INPUT_LEN);
	return SECFailure;
    }

    inlen -= tagBytes;
    intag = inbuf + inlen;

    /* verify the block */
    rv = gcmHash_Update(&gcm->ghash_context, inbuf, inlen, blocksize);
    if (rv != SECSuccess) {
	return SECFailure;
    }
    rv = gcm_GetTag(gcm, tag, &len, blocksize, blocksize);
    if (rv != SECSuccess) {
	return SECFailure;
    }
    /* Don't decrypt if we can't authenticate the encrypted data!
     * This assumes that if tagBits is not a multiple of 8, intag will
     * preserve the masked off missing bits.  */
    if (NSS_SecureMemcmp(tag, intag, tagBytes) != 0) {
	/* force a CKR_ENCRYPTED_DATA_INVALID error at in softoken */
	PORT_SetError(SEC_ERROR_BAD_DATA);
	return SECFailure;
    }
    /* finish the decryption */
    return CTR_Update(&gcm->ctr_context, outbuf, outlen, maxout,
			  inbuf, inlen, blocksize);
}