diff options
Diffstat (limited to 'openssl/crypto/ec/ec_mult.c')
| -rw-r--r-- | openssl/crypto/ec/ec_mult.c | 1572 |
1 files changed, 772 insertions, 800 deletions
diff --git a/openssl/crypto/ec/ec_mult.c b/openssl/crypto/ec/ec_mult.c index e81200b25..23b8c3089 100644 --- a/openssl/crypto/ec/ec_mult.c +++ b/openssl/crypto/ec/ec_mult.c @@ -10,7 +10,7 @@ * are met: * * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. + * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in @@ -67,7 +67,6 @@ #include "ec_lcl.h" - /* * This file implements the wNAF-based interleaving multi-exponentation method * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>); @@ -75,114 +74,107 @@ * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#fastexp>). */ - - - /* structure for precomputed multiples of the generator */ typedef struct ec_pre_comp_st { - const EC_GROUP *group; /* parent EC_GROUP object */ - size_t blocksize; /* block size for wNAF splitting */ - size_t numblocks; /* max. number of blocks for which we have precomputation */ - size_t w; /* window size */ - EC_POINT **points; /* array with pre-calculated multiples of generator: - * 'num' pointers to EC_POINT objects followed by a NULL */ - size_t num; /* numblocks * 2^(w-1) */ - int references; + const EC_GROUP *group; /* parent EC_GROUP object */ + size_t blocksize; /* block size for wNAF splitting */ + size_t numblocks; /* max. number of blocks for which we have + * precomputation */ + size_t w; /* window size */ + EC_POINT **points; /* array with pre-calculated multiples of + * generator: 'num' pointers to EC_POINT + * objects followed by a NULL */ + size_t num; /* numblocks * 2^(w-1) */ + int references; } EC_PRE_COMP; - + /* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */ static void *ec_pre_comp_dup(void *); static void ec_pre_comp_free(void *); static void ec_pre_comp_clear_free(void *); static EC_PRE_COMP *ec_pre_comp_new(const EC_GROUP *group) - { - EC_PRE_COMP *ret = NULL; - - if (!group) - return NULL; - - ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP)); - if (!ret) - { - ECerr(EC_F_EC_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE); - return ret; - } - ret->group = group; - ret->blocksize = 8; /* default */ - ret->numblocks = 0; - ret->w = 4; /* default */ - ret->points = NULL; - ret->num = 0; - ret->references = 1; - return ret; - } +{ + EC_PRE_COMP *ret = NULL; + + if (!group) + return NULL; + + ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP)); + if (!ret) { + ECerr(EC_F_EC_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE); + return ret; + } + ret->group = group; + ret->blocksize = 8; /* default */ + ret->numblocks = 0; + ret->w = 4; /* default */ + ret->points = NULL; + ret->num = 0; + ret->references = 1; + return ret; +} static void *ec_pre_comp_dup(void *src_) - { - EC_PRE_COMP *src = src_; +{ + EC_PRE_COMP *src = src_; - /* no need to actually copy, these objects never change! */ + /* no need to actually copy, these objects never change! */ - CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP); + CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP); - return src_; - } + return src_; +} static void ec_pre_comp_free(void *pre_) - { - int i; - EC_PRE_COMP *pre = pre_; +{ + int i; + EC_PRE_COMP *pre = pre_; - if (!pre) - return; + if (!pre) + return; - i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); - if (i > 0) - return; + i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); + if (i > 0) + return; - if (pre->points) - { - EC_POINT **p; + if (pre->points) { + EC_POINT **p; - for (p = pre->points; *p != NULL; p++) - EC_POINT_free(*p); - OPENSSL_free(pre->points); - } - OPENSSL_free(pre); - } + for (p = pre->points; *p != NULL; p++) + EC_POINT_free(*p); + OPENSSL_free(pre->points); + } + OPENSSL_free(pre); +} static void ec_pre_comp_clear_free(void *pre_) - { - int i; - EC_PRE_COMP *pre = pre_; - - if (!pre) - return; - - i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); - if (i > 0) - return; - - if (pre->points) - { - EC_POINT **p; - - for (p = pre->points; *p != NULL; p++) - { - EC_POINT_clear_free(*p); - OPENSSL_cleanse(p, sizeof *p); - } - OPENSSL_free(pre->points); - } - OPENSSL_cleanse(pre, sizeof *pre); - OPENSSL_free(pre); - } - - - - -/* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'. +{ + int i; + EC_PRE_COMP *pre = pre_; + + if (!pre) + return; + + i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); + if (i > 0) + return; + + if (pre->points) { + EC_POINT **p; + + for (p = pre->points; *p != NULL; p++) { + EC_POINT_clear_free(*p); + OPENSSL_cleanse(p, sizeof *p); + } + OPENSSL_free(pre->points); + } + OPENSSL_cleanse(pre, sizeof *pre); + OPENSSL_free(pre); +} + +/*- + * Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'. * This is an array r[] of values that are either zero or odd with an * absolute value less than 2^w satisfying * scalar = \sum_j r[j]*2^j @@ -191,563 +183,546 @@ static void ec_pre_comp_clear_free(void *pre_) * w-1 zeros away from that next non-zero digit. */ static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len) - { - int window_val; - int ok = 0; - signed char *r = NULL; - int sign = 1; - int bit, next_bit, mask; - size_t len = 0, j; - - if (BN_is_zero(scalar)) - { - r = OPENSSL_malloc(1); - if (!r) - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE); - goto err; - } - r[0] = 0; - *ret_len = 1; - return r; - } - - if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolute values less than 2^7 */ - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); - goto err; - } - bit = 1 << w; /* at most 128 */ - next_bit = bit << 1; /* at most 256 */ - mask = next_bit - 1; /* at most 255 */ - - if (BN_is_negative(scalar)) - { - sign = -1; - } - - if (scalar->d == NULL || scalar->top == 0) - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); - goto err; - } - - len = BN_num_bits(scalar); - r = OPENSSL_malloc(len + 1); /* modified wNAF may be one digit longer than binary representation - * (*ret_len will be set to the actual length, i.e. at most - * BN_num_bits(scalar) + 1) */ - if (r == NULL) - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE); - goto err; - } - window_val = scalar->d[0] & mask; - j = 0; - while ((window_val != 0) || (j + w + 1 < len)) /* if j+w+1 >= len, window_val will not increase */ - { - int digit = 0; - - /* 0 <= window_val <= 2^(w+1) */ - - if (window_val & 1) - { - /* 0 < window_val < 2^(w+1) */ - - if (window_val & bit) - { - digit = window_val - next_bit; /* -2^w < digit < 0 */ - -#if 1 /* modified wNAF */ - if (j + w + 1 >= len) - { - /* special case for generating modified wNAFs: - * no new bits will be added into window_val, - * so using a positive digit here will decrease - * the total length of the representation */ - - digit = window_val & (mask >> 1); /* 0 < digit < 2^w */ - } +{ + int window_val; + int ok = 0; + signed char *r = NULL; + int sign = 1; + int bit, next_bit, mask; + size_t len = 0, j; + + if (BN_is_zero(scalar)) { + r = OPENSSL_malloc(1); + if (!r) { + ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE); + goto err; + } + r[0] = 0; + *ret_len = 1; + return r; + } + + if (w <= 0 || w > 7) { /* 'signed char' can represent integers with + * absolute values less than 2^7 */ + ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); + goto err; + } + bit = 1 << w; /* at most 128 */ + next_bit = bit << 1; /* at most 256 */ + mask = next_bit - 1; /* at most 255 */ + + if (BN_is_negative(scalar)) { + sign = -1; + } + + if (scalar->d == NULL || scalar->top == 0) { + ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); + goto err; + } + + len = BN_num_bits(scalar); + r = OPENSSL_malloc(len + 1); /* modified wNAF may be one digit longer + * than binary representation (*ret_len will + * be set to the actual length, i.e. at most + * BN_num_bits(scalar) + 1) */ + if (r == NULL) { + ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE); + goto err; + } + window_val = scalar->d[0] & mask; + j = 0; + while ((window_val != 0) || (j + w + 1 < len)) { /* if j+w+1 >= len, + * window_val will not + * increase */ + int digit = 0; + + /* 0 <= window_val <= 2^(w+1) */ + + if (window_val & 1) { + /* 0 < window_val < 2^(w+1) */ + + if (window_val & bit) { + digit = window_val - next_bit; /* -2^w < digit < 0 */ + +#if 1 /* modified wNAF */ + if (j + w + 1 >= len) { + /* + * special case for generating modified wNAFs: no new + * bits will be added into window_val, so using a + * positive digit here will decrease the total length of + * the representation + */ + + digit = window_val & (mask >> 1); /* 0 < digit < 2^w */ + } #endif - } - else - { - digit = window_val; /* 0 < digit < 2^w */ - } - - if (digit <= -bit || digit >= bit || !(digit & 1)) - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); - goto err; - } - - window_val -= digit; - - /* now window_val is 0 or 2^(w+1) in standard wNAF generation; - * for modified window NAFs, it may also be 2^w - */ - if (window_val != 0 && window_val != next_bit && window_val != bit) - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); - goto err; - } - } - - r[j++] = sign * digit; - - window_val >>= 1; - window_val += bit * BN_is_bit_set(scalar, j + w); - - if (window_val > next_bit) - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); - goto err; - } - } - - if (j > len + 1) - { - ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); - goto err; - } - len = j; - ok = 1; + } else { + digit = window_val; /* 0 < digit < 2^w */ + } + + if (digit <= -bit || digit >= bit || !(digit & 1)) { + ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); + goto err; + } + + window_val -= digit; + + /* + * now window_val is 0 or 2^(w+1) in standard wNAF generation; + * for modified window NAFs, it may also be 2^w + */ + if (window_val != 0 && window_val != next_bit + && window_val != bit) { + ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); + goto err; + } + } + + r[j++] = sign * digit; + + window_val >>= 1; + window_val += bit * BN_is_bit_set(scalar, j + w); + + if (window_val > next_bit) { + ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); + goto err; + } + } + + if (j > len + 1) { + ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR); + goto err; + } + len = j; + ok = 1; err: - if (!ok) - { - OPENSSL_free(r); - r = NULL; - } - if (ok) - *ret_len = len; - return r; - } - - -/* TODO: table should be optimised for the wNAF-based implementation, - * sometimes smaller windows will give better performance - * (thus the boundaries should be increased) + if (!ok) { + OPENSSL_free(r); + r = NULL; + } + if (ok) + *ret_len = len; + return r; +} + +/* + * TODO: table should be optimised for the wNAF-based implementation, + * sometimes smaller windows will give better performance (thus the + * boundaries should be increased) */ #define EC_window_bits_for_scalar_size(b) \ - ((size_t) \ - ((b) >= 2000 ? 6 : \ - (b) >= 800 ? 5 : \ - (b) >= 300 ? 4 : \ - (b) >= 70 ? 3 : \ - (b) >= 20 ? 2 : \ - 1)) - -/* Compute + ((size_t) \ + ((b) >= 2000 ? 6 : \ + (b) >= 800 ? 5 : \ + (b) >= 300 ? 4 : \ + (b) >= 70 ? 3 : \ + (b) >= 20 ? 2 : \ + 1)) + +/*- + * Compute * \sum scalars[i]*points[i], * also including * scalar*generator * in the addition if scalar != NULL */ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, - size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx) - { - BN_CTX *new_ctx = NULL; - const EC_POINT *generator = NULL; - EC_POINT *tmp = NULL; - size_t totalnum; - size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */ - size_t pre_points_per_block = 0; - size_t i, j; - int k; - int r_is_inverted = 0; - int r_is_at_infinity = 1; - size_t *wsize = NULL; /* individual window sizes */ - signed char **wNAF = NULL; /* individual wNAFs */ - size_t *wNAF_len = NULL; - size_t max_len = 0; - size_t num_val; - EC_POINT **val = NULL; /* precomputation */ - EC_POINT **v; - EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' or 'pre_comp->points' */ - const EC_PRE_COMP *pre_comp = NULL; - int num_scalar = 0; /* flag: will be set to 1 if 'scalar' must be treated like other scalars, - * i.e. precomputation is not available */ - int ret = 0; - - if (group->meth != r->meth) - { - ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); - return 0; - } - - if ((scalar == NULL) && (num == 0)) - { - return EC_POINT_set_to_infinity(group, r); - } - - for (i = 0; i < num; i++) - { - if (group->meth != points[i]->meth) - { - ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); - return 0; - } - } - - if (ctx == NULL) - { - ctx = new_ctx = BN_CTX_new(); - if (ctx == NULL) - goto err; - } - - if (scalar != NULL) - { - generator = EC_GROUP_get0_generator(group); - if (generator == NULL) - { - ECerr(EC_F_EC_WNAF_MUL, EC_R_UNDEFINED_GENERATOR); - goto err; - } - - /* look if we can use precomputed multiples of generator */ - - pre_comp = EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free); - - if (pre_comp && pre_comp->numblocks && (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == 0)) - { - blocksize = pre_comp->blocksize; - - /* determine maximum number of blocks that wNAF splitting may yield - * (NB: maximum wNAF length is bit length plus one) */ - numblocks = (BN_num_bits(scalar) / blocksize) + 1; - - /* we cannot use more blocks than we have precomputation for */ - if (numblocks > pre_comp->numblocks) - numblocks = pre_comp->numblocks; - - pre_points_per_block = (size_t)1 << (pre_comp->w - 1); - - /* check that pre_comp looks sane */ - if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block)) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); - goto err; - } - } - else - { - /* can't use precomputation */ - pre_comp = NULL; - numblocks = 1; - num_scalar = 1; /* treat 'scalar' like 'num'-th element of 'scalars' */ - } - } - - totalnum = num + numblocks; - - wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]); - wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]); - wNAF = OPENSSL_malloc((totalnum + 1) * sizeof wNAF[0]); /* includes space for pivot */ - val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]); - - /* Ensure wNAF is initialised in case we end up going to err */ - if (wNAF) wNAF[0] = NULL; /* preliminary pivot */ - - if (!wsize || !wNAF_len || !wNAF || !val_sub) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); - goto err; - } - - /* num_val will be the total number of temporarily precomputed points */ - num_val = 0; - - for (i = 0; i < num + num_scalar; i++) - { - size_t bits; - - bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar); - wsize[i] = EC_window_bits_for_scalar_size(bits); - num_val += (size_t)1 << (wsize[i] - 1); - wNAF[i + 1] = NULL; /* make sure we always have a pivot */ - wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i]); - if (wNAF[i] == NULL) - goto err; - if (wNAF_len[i] > max_len) - max_len = wNAF_len[i]; - } - - if (numblocks) - { - /* we go here iff scalar != NULL */ - - if (pre_comp == NULL) - { - if (num_scalar != 1) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); - goto err; - } - /* we have already generated a wNAF for 'scalar' */ - } - else - { - signed char *tmp_wNAF = NULL; - size_t tmp_len = 0; - - if (num_scalar != 0) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); - goto err; - } - - /* use the window size for which we have precomputation */ - wsize[num] = pre_comp->w; - tmp_wNAF = compute_wNAF(scalar, wsize[num], &tmp_len); - if (!tmp_wNAF) - goto err; - - if (tmp_len <= max_len) - { - /* One of the other wNAFs is at least as long - * as the wNAF belonging to the generator, - * so wNAF splitting will not buy us anything. */ - - numblocks = 1; - totalnum = num + 1; /* don't use wNAF splitting */ - wNAF[num] = tmp_wNAF; - wNAF[num + 1] = NULL; - wNAF_len[num] = tmp_len; - if (tmp_len > max_len) - max_len = tmp_len; - /* pre_comp->points starts with the points that we need here: */ - val_sub[num] = pre_comp->points; - } - else - { - /* don't include tmp_wNAF directly into wNAF array - * - use wNAF splitting and include the blocks */ - - signed char *pp; - EC_POINT **tmp_points; - - if (tmp_len < numblocks * blocksize) - { - /* possibly we can do with fewer blocks than estimated */ - numblocks = (tmp_len + blocksize - 1) / blocksize; - if (numblocks > pre_comp->numblocks) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); - goto err; - } - totalnum = num + numblocks; - } - - /* split wNAF in 'numblocks' parts */ - pp = tmp_wNAF; - tmp_points = pre_comp->points; - - for (i = num; i < totalnum; i++) - { - if (i < totalnum - 1) - { - wNAF_len[i] = blocksize; - if (tmp_len < blocksize) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); - goto err; - } - tmp_len -= blocksize; - } - else - /* last block gets whatever is left - * (this could be more or less than 'blocksize'!) */ - wNAF_len[i] = tmp_len; - - wNAF[i + 1] = NULL; - wNAF[i] = OPENSSL_malloc(wNAF_len[i]); - if (wNAF[i] == NULL) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); - OPENSSL_free(tmp_wNAF); - goto err; - } - memcpy(wNAF[i], pp, wNAF_len[i]); - if (wNAF_len[i] > max_len) - max_len = wNAF_len[i]; - - if (*tmp_points == NULL) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); - OPENSSL_free(tmp_wNAF); - goto err; - } - val_sub[i] = tmp_points; - tmp_points += pre_points_per_block; - pp += blocksize; - } - OPENSSL_free(tmp_wNAF); - } - } - } - - /* All points we precompute now go into a single array 'val'. - * 'val_sub[i]' is a pointer to the subarray for the i-th point, - * or to a subarray of 'pre_comp->points' if we already have precomputation. */ - val = OPENSSL_malloc((num_val + 1) * sizeof val[0]); - if (val == NULL) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); - goto err; - } - val[num_val] = NULL; /* pivot element */ - - /* allocate points for precomputation */ - v = val; - for (i = 0; i < num + num_scalar; i++) - { - val_sub[i] = v; - for (j = 0; j < ((size_t)1 << (wsize[i] - 1)); j++) - { - *v = EC_POINT_new(group); - if (*v == NULL) goto err; - v++; - } - } - if (!(v == val + num_val)) - { - ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); - goto err; - } - - if (!(tmp = EC_POINT_new(group))) - goto err; - - /* prepare precomputed values: - * val_sub[i][0] := points[i] - * val_sub[i][1] := 3 * points[i] - * val_sub[i][2] := 5 * points[i] - * ... - */ - for (i = 0; i < num + num_scalar; i++) - { - if (i < num) - { - if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err; - } - else - { - if (!EC_POINT_copy(val_sub[i][0], generator)) goto err; - } - - if (wsize[i] > 1) - { - if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err; - for (j = 1; j < ((size_t)1 << (wsize[i] - 1)); j++) - { - if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err; - } - } - } - -#if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */ - if (!EC_POINTs_make_affine(group, num_val, val, ctx)) - goto err; + size_t num, const EC_POINT *points[], const BIGNUM *scalars[], + BN_CTX *ctx) +{ + BN_CTX *new_ctx = NULL; + const EC_POINT *generator = NULL; + EC_POINT *tmp = NULL; + size_t totalnum; + size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */ + size_t pre_points_per_block = 0; + size_t i, j; + int k; + int r_is_inverted = 0; + int r_is_at_infinity = 1; + size_t *wsize = NULL; /* individual window sizes */ + signed char **wNAF = NULL; /* individual wNAFs */ + size_t *wNAF_len = NULL; + size_t max_len = 0; + size_t num_val; + EC_POINT **val = NULL; /* precomputation */ + EC_POINT **v; + EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' or + * 'pre_comp->points' */ + const EC_PRE_COMP *pre_comp = NULL; + int num_scalar = 0; /* flag: will be set to 1 if 'scalar' must be + * treated like other scalars, i.e. + * precomputation is not available */ + int ret = 0; + + if (group->meth != r->meth) { + ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); + return 0; + } + + if ((scalar == NULL) && (num == 0)) { + return EC_POINT_set_to_infinity(group, r); + } + + for (i = 0; i < num; i++) { + if (group->meth != points[i]->meth) { + ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS); + return 0; + } + } + + if (ctx == NULL) { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + goto err; + } + + if (scalar != NULL) { + generator = EC_GROUP_get0_generator(group); + if (generator == NULL) { + ECerr(EC_F_EC_WNAF_MUL, EC_R_UNDEFINED_GENERATOR); + goto err; + } + + /* look if we can use precomputed multiples of generator */ + + pre_comp = + EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, + ec_pre_comp_free, ec_pre_comp_clear_free); + + if (pre_comp && pre_comp->numblocks + && (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == + 0)) { + blocksize = pre_comp->blocksize; + + /* + * determine maximum number of blocks that wNAF splitting may + * yield (NB: maximum wNAF length is bit length plus one) + */ + numblocks = (BN_num_bits(scalar) / blocksize) + 1; + + /* + * we cannot use more blocks than we have precomputation for + */ + if (numblocks > pre_comp->numblocks) + numblocks = pre_comp->numblocks; + + pre_points_per_block = (size_t)1 << (pre_comp->w - 1); + + /* check that pre_comp looks sane */ + if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block)) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); + goto err; + } + } else { + /* can't use precomputation */ + pre_comp = NULL; + numblocks = 1; + num_scalar = 1; /* treat 'scalar' like 'num'-th element of + * 'scalars' */ + } + } + + totalnum = num + numblocks; + + wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]); + wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]); + wNAF = OPENSSL_malloc((totalnum + 1) * sizeof wNAF[0]); /* includes space + * for pivot */ + val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]); + + /* Ensure wNAF is initialised in case we end up going to err */ + if (wNAF) + wNAF[0] = NULL; /* preliminary pivot */ + + if (!wsize || !wNAF_len || !wNAF || !val_sub) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); + goto err; + } + + /* + * num_val will be the total number of temporarily precomputed points + */ + num_val = 0; + + for (i = 0; i < num + num_scalar; i++) { + size_t bits; + + bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar); + wsize[i] = EC_window_bits_for_scalar_size(bits); + num_val += (size_t)1 << (wsize[i] - 1); + wNAF[i + 1] = NULL; /* make sure we always have a pivot */ + wNAF[i] = + compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], + &wNAF_len[i]); + if (wNAF[i] == NULL) + goto err; + if (wNAF_len[i] > max_len) + max_len = wNAF_len[i]; + } + + if (numblocks) { + /* we go here iff scalar != NULL */ + + if (pre_comp == NULL) { + if (num_scalar != 1) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); + goto err; + } + /* we have already generated a wNAF for 'scalar' */ + } else { + signed char *tmp_wNAF = NULL; + size_t tmp_len = 0; + + if (num_scalar != 0) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); + goto err; + } + + /* + * use the window size for which we have precomputation + */ + wsize[num] = pre_comp->w; + tmp_wNAF = compute_wNAF(scalar, wsize[num], &tmp_len); + if (!tmp_wNAF) + goto err; + + if (tmp_len <= max_len) { + /* + * One of the other wNAFs is at least as long as the wNAF + * belonging to the generator, so wNAF splitting will not buy + * us anything. + */ + + numblocks = 1; + totalnum = num + 1; /* don't use wNAF splitting */ + wNAF[num] = tmp_wNAF; + wNAF[num + 1] = NULL; + wNAF_len[num] = tmp_len; + if (tmp_len > max_len) + max_len = tmp_len; + /* + * pre_comp->points starts with the points that we need here: + */ + val_sub[num] = pre_comp->points; + } else { + /* + * don't include tmp_wNAF directly into wNAF array - use wNAF + * splitting and include the blocks + */ + + signed char *pp; + EC_POINT **tmp_points; + + if (tmp_len < numblocks * blocksize) { + /* + * possibly we can do with fewer blocks than estimated + */ + numblocks = (tmp_len + blocksize - 1) / blocksize; + if (numblocks > pre_comp->numblocks) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); + goto err; + } + totalnum = num + numblocks; + } + + /* split wNAF in 'numblocks' parts */ + pp = tmp_wNAF; + tmp_points = pre_comp->points; + + for (i = num; i < totalnum; i++) { + if (i < totalnum - 1) { + wNAF_len[i] = blocksize; + if (tmp_len < blocksize) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); + goto err; + } + tmp_len -= blocksize; + } else + /* + * last block gets whatever is left (this could be + * more or less than 'blocksize'!) + */ + wNAF_len[i] = tmp_len; + + wNAF[i + 1] = NULL; + wNAF[i] = OPENSSL_malloc(wNAF_len[i]); + if (wNAF[i] == NULL) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); + OPENSSL_free(tmp_wNAF); + goto err; + } + memcpy(wNAF[i], pp, wNAF_len[i]); + if (wNAF_len[i] > max_len) + max_len = wNAF_len[i]; + + if (*tmp_points == NULL) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); + OPENSSL_free(tmp_wNAF); + goto err; + } + val_sub[i] = tmp_points; + tmp_points += pre_points_per_block; + pp += blocksize; + } + OPENSSL_free(tmp_wNAF); + } + } + } + + /* + * All points we precompute now go into a single array 'val'. + * 'val_sub[i]' is a pointer to the subarray for the i-th point, or to a + * subarray of 'pre_comp->points' if we already have precomputation. + */ + val = OPENSSL_malloc((num_val + 1) * sizeof val[0]); + if (val == NULL) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE); + goto err; + } + val[num_val] = NULL; /* pivot element */ + + /* allocate points for precomputation */ + v = val; + for (i = 0; i < num + num_scalar; i++) { + val_sub[i] = v; + for (j = 0; j < ((size_t)1 << (wsize[i] - 1)); j++) { + *v = EC_POINT_new(group); + if (*v == NULL) + goto err; + v++; + } + } + if (!(v == val + num_val)) { + ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR); + goto err; + } + + if (!(tmp = EC_POINT_new(group))) + goto err; + + /*- + * prepare precomputed values: + * val_sub[i][0] := points[i] + * val_sub[i][1] := 3 * points[i] + * val_sub[i][2] := 5 * points[i] + * ... + */ + for (i = 0; i < num + num_scalar; i++) { + if (i < num) { + if (!EC_POINT_copy(val_sub[i][0], points[i])) + goto err; + } else { + if (!EC_POINT_copy(val_sub[i][0], generator)) + goto err; + } + + if (wsize[i] > 1) { + if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) + goto err; + for (j = 1; j < ((size_t)1 << (wsize[i] - 1)); j++) { + if (!EC_POINT_add + (group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) + goto err; + } + } + } + +#if 1 /* optional; EC_window_bits_for_scalar_size + * assumes we do this step */ + if (!EC_POINTs_make_affine(group, num_val, val, ctx)) + goto err; #endif - r_is_at_infinity = 1; - - for (k = max_len - 1; k >= 0; k--) - { - if (!r_is_at_infinity) - { - if (!EC_POINT_dbl(group, r, r, ctx)) goto err; - } - - for (i = 0; i < totalnum; i++) - { - if (wNAF_len[i] > (size_t)k) - { - int digit = wNAF[i][k]; - int is_neg; - - if (digit) - { - is_neg = digit < 0; - - if (is_neg) - digit = -digit; - - if (is_neg != r_is_inverted) - { - if (!r_is_at_infinity) - { - if (!EC_POINT_invert(group, r, ctx)) goto err; - } - r_is_inverted = !r_is_inverted; - } - - /* digit > 0 */ - - if (r_is_at_infinity) - { - if (!EC_POINT_copy(r, val_sub[i][digit >> 1])) goto err; - r_is_at_infinity = 0; - } - else - { - if (!EC_POINT_add(group, r, r, val_sub[i][digit >> 1], ctx)) goto err; - } - } - } - } - } - - if (r_is_at_infinity) - { - if (!EC_POINT_set_to_infinity(group, r)) goto err; - } - else - { - if (r_is_inverted) - if (!EC_POINT_invert(group, r, ctx)) goto err; - } - - ret = 1; + r_is_at_infinity = 1; + + for (k = max_len - 1; k >= 0; k--) { + if (!r_is_at_infinity) { + if (!EC_POINT_dbl(group, r, r, ctx)) + goto err; + } + + for (i = 0; i < totalnum; i++) { + if (wNAF_len[i] > (size_t)k) { + int digit = wNAF[i][k]; + int is_neg; + + if (digit) { + is_neg = digit < 0; + + if (is_neg) + digit = -digit; + + if (is_neg != r_is_inverted) { + if (!r_is_at_infinity) { + if (!EC_POINT_invert(group, r, ctx)) + goto err; + } + r_is_inverted = !r_is_inverted; + } + + /* digit > 0 */ + + if (r_is_at_infinity) { + if (!EC_POINT_copy(r, val_sub[i][digit >> 1])) + goto err; + r_is_at_infinity = 0; + } else { + if (!EC_POINT_add + (group, r, r, val_sub[i][digit >> 1], ctx)) + goto err; + } + } + } + } + } + + if (r_is_at_infinity) { + if (!EC_POINT_set_to_infinity(group, r)) + goto err; + } else { + if (r_is_inverted) + if (!EC_POINT_invert(group, r, ctx)) + goto err; + } + + ret = 1; err: - if (new_ctx != NULL) - BN_CTX_free(new_ctx); - if (tmp != NULL) - EC_POINT_free(tmp); - if (wsize != NULL) - OPENSSL_free(wsize); - if (wNAF_len != NULL) - OPENSSL_free(wNAF_len); - if (wNAF != NULL) - { - signed char **w; - - for (w = wNAF; *w != NULL; w++) - OPENSSL_free(*w); - - OPENSSL_free(wNAF); - } - if (val != NULL) - { - for (v = val; *v != NULL; v++) - EC_POINT_clear_free(*v); - - OPENSSL_free(val); - } - if (val_sub != NULL) - { - OPENSSL_free(val_sub); - } - return ret; - } - - -/* ec_wNAF_precompute_mult() + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + if (tmp != NULL) + EC_POINT_free(tmp); + if (wsize != NULL) + OPENSSL_free(wsize); + if (wNAF_len != NULL) + OPENSSL_free(wNAF_len); + if (wNAF != NULL) { + signed char **w; + + for (w = wNAF; *w != NULL; w++) + OPENSSL_free(*w); + + OPENSSL_free(wNAF); + } + if (val != NULL) { + for (v = val; *v != NULL; v++) + EC_POINT_clear_free(*v); + + OPENSSL_free(val); + } + if (val_sub != NULL) { + OPENSSL_free(val_sub); + } + return ret; +} + +/*- + * ec_wNAF_precompute_mult() * creates an EC_PRE_COMP object with preprecomputed multiples of the generator * for use with wNAF splitting as implemented in ec_wNAF_mul(). - * + * * 'pre_comp->points' is an array of multiples of the generator * of the following form: * points[0] = generator; @@ -764,178 +739,175 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, * points[2^(w-1)*numblocks] = NULL */ int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx) - { - const EC_POINT *generator; - EC_POINT *tmp_point = NULL, *base = NULL, **var; - BN_CTX *new_ctx = NULL; - BIGNUM *order; - size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num; - EC_POINT **points = NULL; - EC_PRE_COMP *pre_comp; - int ret = 0; - - /* if there is an old EC_PRE_COMP object, throw it away */ - EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free); - - if ((pre_comp = ec_pre_comp_new(group)) == NULL) - return 0; - - generator = EC_GROUP_get0_generator(group); - if (generator == NULL) - { - ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR); - goto err; - } - - if (ctx == NULL) - { - ctx = new_ctx = BN_CTX_new(); - if (ctx == NULL) - goto err; - } - - BN_CTX_start(ctx); - order = BN_CTX_get(ctx); - if (order == NULL) goto err; - - if (!EC_GROUP_get_order(group, order, ctx)) goto err; - if (BN_is_zero(order)) - { - ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER); - goto err; - } - - bits = BN_num_bits(order); - /* The following parameters mean we precompute (approximately) - * one point per bit. - * - * TBD: The combination 8, 4 is perfect for 160 bits; for other - * bit lengths, other parameter combinations might provide better - * efficiency. - */ - blocksize = 8; - w = 4; - if (EC_window_bits_for_scalar_size(bits) > w) - { - /* let's not make the window too small ... */ - w = EC_window_bits_for_scalar_size(bits); - } - - numblocks = (bits + blocksize - 1) / blocksize; /* max. number of blocks to use for wNAF splitting */ - - pre_points_per_block = (size_t)1 << (w - 1); - num = pre_points_per_block * numblocks; /* number of points to compute and store */ - - points = OPENSSL_malloc(sizeof (EC_POINT*)*(num + 1)); - if (!points) - { - ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); - goto err; - } - - var = points; - var[num] = NULL; /* pivot */ - for (i = 0; i < num; i++) - { - if ((var[i] = EC_POINT_new(group)) == NULL) - { - ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); - goto err; - } - } - - if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group))) - { - ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); - goto err; - } - - if (!EC_POINT_copy(base, generator)) - goto err; - - /* do the precomputation */ - for (i = 0; i < numblocks; i++) - { - size_t j; - - if (!EC_POINT_dbl(group, tmp_point, base, ctx)) - goto err; - - if (!EC_POINT_copy(*var++, base)) - goto err; - - for (j = 1; j < pre_points_per_block; j++, var++) - { - /* calculate odd multiples of the current base point */ - if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx)) - goto err; - } - - if (i < numblocks - 1) - { - /* get the next base (multiply current one by 2^blocksize) */ - size_t k; - - if (blocksize <= 2) - { - ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_INTERNAL_ERROR); - goto err; - } - - if (!EC_POINT_dbl(group, base, tmp_point, ctx)) - goto err; - for (k = 2; k < blocksize; k++) - { - if (!EC_POINT_dbl(group,base,base,ctx)) - goto err; - } - } - } - - if (!EC_POINTs_make_affine(group, num, points, ctx)) - goto err; - - pre_comp->group = group; - pre_comp->blocksize = blocksize; - pre_comp->numblocks = numblocks; - pre_comp->w = w; - pre_comp->points = points; - points = NULL; - pre_comp->num = num; - - if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp, - ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free)) - goto err; - pre_comp = NULL; - - ret = 1; +{ + const EC_POINT *generator; + EC_POINT *tmp_point = NULL, *base = NULL, **var; + BN_CTX *new_ctx = NULL; + BIGNUM *order; + size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num; + EC_POINT **points = NULL; + EC_PRE_COMP *pre_comp; + int ret = 0; + + /* if there is an old EC_PRE_COMP object, throw it away */ + EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, + ec_pre_comp_free, ec_pre_comp_clear_free); + + if ((pre_comp = ec_pre_comp_new(group)) == NULL) + return 0; + + generator = EC_GROUP_get0_generator(group); + if (generator == NULL) { + ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR); + goto err; + } + + if (ctx == NULL) { + ctx = new_ctx = BN_CTX_new(); + if (ctx == NULL) + goto err; + } + + BN_CTX_start(ctx); + order = BN_CTX_get(ctx); + if (order == NULL) + goto err; + + if (!EC_GROUP_get_order(group, order, ctx)) + goto err; + if (BN_is_zero(order)) { + ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER); + goto err; + } + + bits = BN_num_bits(order); + /* + * The following parameters mean we precompute (approximately) one point + * per bit. TBD: The combination 8, 4 is perfect for 160 bits; for other + * bit lengths, other parameter combinations might provide better + * efficiency. + */ + blocksize = 8; + w = 4; + if (EC_window_bits_for_scalar_size(bits) > w) { + /* let's not make the window too small ... */ + w = EC_window_bits_for_scalar_size(bits); + } + + numblocks = (bits + blocksize - 1) / blocksize; /* max. number of blocks + * to use for wNAF + * splitting */ + + pre_points_per_block = (size_t)1 << (w - 1); + num = pre_points_per_block * numblocks; /* number of points to compute + * and store */ + + points = OPENSSL_malloc(sizeof(EC_POINT *) * (num + 1)); + if (!points) { + ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); + goto err; + } + + var = points; + var[num] = NULL; /* pivot */ + for (i = 0; i < num; i++) { + if ((var[i] = EC_POINT_new(group)) == NULL) { + ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); + goto err; + } + } + + if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group))) { + ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE); + goto err; + } + + if (!EC_POINT_copy(base, generator)) + goto err; + + /* do the precomputation */ + for (i = 0; i < numblocks; i++) { + size_t j; + + if (!EC_POINT_dbl(group, tmp_point, base, ctx)) + goto err; + + if (!EC_POINT_copy(*var++, base)) + goto err; + + for (j = 1; j < pre_points_per_block; j++, var++) { + /* + * calculate odd multiples of the current base point + */ + if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx)) + goto err; + } + + if (i < numblocks - 1) { + /* + * get the next base (multiply current one by 2^blocksize) + */ + size_t k; + + if (blocksize <= 2) { + ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_INTERNAL_ERROR); + goto err; + } + + if (!EC_POINT_dbl(group, base, tmp_point, ctx)) + goto err; + for (k = 2; k < blocksize; k++) { + if (!EC_POINT_dbl(group, base, base, ctx)) + goto err; + } + } + } + + if (!EC_POINTs_make_affine(group, num, points, ctx)) + goto err; + + pre_comp->group = group; + pre_comp->blocksize = blocksize; + pre_comp->numblocks = numblocks; + pre_comp->w = w; + pre_comp->points = points; + points = NULL; + pre_comp->num = num; + + if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp, + ec_pre_comp_dup, ec_pre_comp_free, + ec_pre_comp_clear_free)) + goto err; + pre_comp = NULL; + + ret = 1; err: - if (ctx != NULL) - BN_CTX_end(ctx); - if (new_ctx != NULL) - BN_CTX_free(new_ctx); - if (pre_comp) - ec_pre_comp_free(pre_comp); - if (points) - { - EC_POINT **p; - - for (p = points; *p != NULL; p++) - EC_POINT_free(*p); - OPENSSL_free(points); - } - if (tmp_point) - EC_POINT_free(tmp_point); - if (base) - EC_POINT_free(base); - return ret; - } - + if (ctx != NULL) + BN_CTX_end(ctx); + if (new_ctx != NULL) + BN_CTX_free(new_ctx); + if (pre_comp) + ec_pre_comp_free(pre_comp); + if (points) { + EC_POINT **p; + + for (p = points; *p != NULL; p++) + EC_POINT_free(*p); + OPENSSL_free(points); + } + if (tmp_point) + EC_POINT_free(tmp_point); + if (base) + EC_POINT_free(base); + return ret; +} int ec_wNAF_have_precompute_mult(const EC_GROUP *group) - { - if (EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free) != NULL) - return 1; - else - return 0; - } +{ + if (EC_EX_DATA_get_data + (group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, + ec_pre_comp_clear_free) != NULL) + return 1; + else + return 0; +} |