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Error checking and memory leak fixes in NISTZ256.

Browse source 
Reviewed-by: Richard Levitte <levitte@openssl.org>
This commit is contained in:
Emilia Kasper 2015-04-27 16:21:48 +02:00
parent 2f5997b7b9
commit e22d2199e2
5 changed files with 52 additions and 31 deletions
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3
crypto/bn/bn_err.c
View file

@ -1,6 +1,6 @@
/* crypto/bn/bn_err.c */
/* ====================================================================
* Copyright (c) 1999-2014 The OpenSSL Project. All rights reserved.
* Copyright (c) 1999-2015 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@ -113,6 +113,7 @@ static ERR_STRING_DATA BN_str_functs[] = {
{ERR_FUNC(BN_F_BN_NEW), "BN_new"},
{ERR_FUNC(BN_F_BN_RAND), "BN_rand"},
{ERR_FUNC(BN_F_BN_RAND_RANGE), "BN_rand_range"},
{ERR_FUNC(BN_F_BN_SET_WORDS), "bn_set_words"},
{ERR_FUNC(BN_F_BN_USUB), "BN_usub"},
{0, NULL}
};

13
crypto/bn/bn_intern.c
View file

@ -233,11 +233,20 @@ void bn_set_static_words(BIGNUM *a, BN_ULONG *words, int size)
a->dmax = a->top = size;
a->neg = 0;
a->flags |= BN_FLG_STATIC_DATA;
bn_correct_top(a);
}
void bn_set_data(BIGNUM *a, const void *data, size_t size)
int bn_set_words(BIGNUM *a, BN_ULONG *words, int num_words)
{
memcpy(a->d, data, size);
if (bn_wexpand(a, num_words) == NULL) {
BNerr(BN_F_BN_SET_WORDS, ERR_R_MALLOC_FAILURE);
return 0;
}
memcpy(a->d, words, sizeof(BN_ULONG) * num_words);
a->top = num_words;
bn_correct_top(a);
return 1;
}
size_t bn_sizeof_BIGNUM(void)

55
crypto/ec/ecp_nistz256.c
View file

@ -1133,6 +1133,7 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group,
const PRECOMP256_ROW *preComputedTable = NULL;
const EC_PRE_COMP *pre_comp = NULL;
const EC_POINT *generator = NULL;
BN_CTX *new_ctx = NULL;
unsigned int idx = 0;
const unsigned int window_size = 7;
const unsigned int mask = (1 << (window_size + 1)) - 1;
@ -1152,6 +1153,7 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group,
ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
return 0;
}
if ((scalar == NULL) && (num == 0))
return EC_POINT_set_to_infinity(group, r);
@ -1162,13 +1164,13 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group,
}
}
/* Need 256 bits for space for all coordinates. */
bn_wexpand(r->X, P256_LIMBS);
bn_wexpand(r->Y, P256_LIMBS);
bn_wexpand(r->Z, P256_LIMBS);
bn_set_top(r->X, P256_LIMBS);
bn_set_top(r->Y, P256_LIMBS);
bn_set_top(r->Z, P256_LIMBS);
if (ctx == NULL) {
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
}
BN_CTX_start(ctx);
if (scalar) {
generator = EC_GROUP_get0_generator(group);
@ -1194,8 +1196,10 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group,
if (!ecp_nistz256_set_from_affine(pre_comp_generator,
group, pre_comp->precomp[0],
ctx))
ctx)) {
EC_POINT_free(pre_comp_generator);
goto err;
}
if (0 == EC_POINT_cmp(group, generator, pre_comp_generator, ctx))
preComputedTable = (const PRECOMP256_ROW *)pre_comp->precomp;
@ -1300,14 +1304,14 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group,
new_scalars = OPENSSL_malloc((num + 1) * sizeof(BIGNUM *));
if (!new_scalars) {
ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE);
return 0;
goto err;
}
new_points = OPENSSL_malloc((num + 1) * sizeof(EC_POINT *));
if (!new_points) {
OPENSSL_free(new_scalars);
ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE);
return 0;
goto err;
}
memcpy(new_scalars, scalars, num * sizeof(BIGNUM *));
@ -1336,18 +1340,20 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group,
OPENSSL_free(scalars);
}
bn_set_data(r->X, p.p.X, sizeof(p.p.X));
bn_set_data(r->Y, p.p.Y, sizeof(p.p.Y));
bn_set_data(r->Z, p.p.Z, sizeof(p.p.Z));
/* Not constant-time, but we're only operating on the public output. */
bn_correct_top(r->X);
bn_correct_top(r->Y);
bn_correct_top(r->Z);
if (!bn_set_words(r->X, p.p.X, P256_LIMBS) ||
!bn_set_words(r->Y, p.p.Y, P256_LIMBS) ||
!bn_set_words(r->Z, p.p.Z, P256_LIMBS)) {
goto err;
}
r->Z_is_one = is_one(p.p.Z);
ret = 1;
err:
err:
if (ctx)
BN_CTX_end(ctx);
BN_CTX_free(new_ctx);
return ret;
}
@ -1360,6 +1366,7 @@ static int ecp_nistz256_get_affine(const EC_GROUP *group,
BN_ULONG x_aff[P256_LIMBS];
BN_ULONG y_aff[P256_LIMBS];
BN_ULONG point_x[P256_LIMBS], point_y[P256_LIMBS], point_z[P256_LIMBS];
BN_ULONG x_ret[P256_LIMBS], y_ret[P256_LIMBS];
if (EC_POINT_is_at_infinity(group, point)) {
ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_POINT_AT_INFINITY);
@ -1378,19 +1385,17 @@ static int ecp_nistz256_get_affine(const EC_GROUP *group,
ecp_nistz256_mul_mont(x_aff, z_inv2, point_x);
if (x != NULL) {
bn_wexpand(x, P256_LIMBS);
bn_set_top(x, P256_LIMBS);
ecp_nistz256_from_mont(bn_get_words(x), x_aff);
bn_correct_top(x);
ecp_nistz256_from_mont(x_ret, x_aff);
if (!bn_set_words(x, x_ret, P256_LIMBS))
return 0;
}
if (y != NULL) {
ecp_nistz256_mul_mont(z_inv3, z_inv3, z_inv2);
ecp_nistz256_mul_mont(y_aff, z_inv3, point_y);
bn_wexpand(y, P256_LIMBS);
bn_set_top(y, P256_LIMBS);
ecp_nistz256_from_mont(bn_get_words(y), y_aff);
bn_correct_top(y);
ecp_nistz256_from_mont(y_ret, y_aff);
if (!bn_set_words(y, y_ret, P256_LIMBS))
return 0;
}
return 1;

11
crypto/include/internal/bn_int.h
View file

@ -102,10 +102,15 @@ BN_ULONG *bn_get_words(const BIGNUM *a);
void bn_set_static_words(BIGNUM *a, BN_ULONG *words, int size);
/*
* Copy data into the BIGNUM. The caller must check that dmax is sufficient to
* hold the data
* Copy words into the BIGNUM |a|, reallocating space as necessary.
* The negative flag of |a| is not modified.
* Returns 1 on success and 0 on failure.
*/
void bn_set_data(BIGNUM *a, const void *data, size_t size);
/*
* |num_words| is int because bn_expand2 takes an int. This is an internal
* function so we simply trust callers not to pass negative values.
*/
int bn_set_words(BIGNUM *a, BN_ULONG *words, int num_words);
size_t bn_sizeof_BIGNUM(void);

1
include/openssl/bn.h
View file

@ -730,6 +730,7 @@ void ERR_load_BN_strings(void);
# define BN_F_BN_NEW 113
# define BN_F_BN_RAND 114
# define BN_F_BN_RAND_RANGE 122
# define BN_F_BN_SET_WORDS 144
# define BN_F_BN_USUB 115
/* Reason codes. */