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Use BN_bn2bin_padded rather than doing math to figure out leading zeros.

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Saves doing it ad-hoc all the time.

Change-Id: Ic1a1180f56eec37c19799649bb8f18237bd617f8
Reviewed-on: https://boringssl-review.googlesource.com/2241
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
David Benjamin
2014-11-10 23:04:52 +00:00
committed by Adam Langley
parent b145c8140b
commit f2f3cfedb7
3 changed files with 30 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files
crypto/ec/oct.c
+22 -31
View File
@@ -81,7 +81,7 @@ static size_t ec_GFp_simple_point2oct(const EC_GROUP *group,
BN_CTX *new_ctx = NULL;
int used_ctx = 0;
BIGNUM *x, *y;
size_t field_len, i, skip;
size_t field_len, i;
if ((form != POINT_CONVERSION_COMPRESSED) &&
(form != POINT_CONVERSION_UNCOMPRESSED) &&
@@ -117,58 +117,45 @@ static size_t ec_GFp_simple_point2oct(const EC_GROUP *group,
if (ctx == NULL) {
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL)
if (ctx == NULL) {
return 0;
}
}
BN_CTX_start(ctx);
used_ctx = 1;
x = BN_CTX_get(ctx);
y = BN_CTX_get(ctx);
if (y == NULL)
if (y == NULL) {
goto err;
}
if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx))
if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx)) {
goto err;
}
if ((form == POINT_CONVERSION_COMPRESSED ||
form == POINT_CONVERSION_HYBRID) &&
BN_is_odd(y))
BN_is_odd(y)) {
buf[0] = form + 1;
else
} else {
buf[0] = form;
}
i = 1;
skip = field_len - BN_num_bytes(x);
if (skip > field_len) {
OPENSSL_PUT_ERROR(EC, ec_GFp_simple_point2oct, ERR_R_INTERNAL_ERROR);
goto err;
}
while (skip > 0) {
buf[i++] = 0;
skip--;
}
skip = BN_bn2bin(x, buf + i);
i += skip;
if (i != 1 + field_len) {
if (!BN_bn2bin_padded(buf + i, field_len, x)) {
OPENSSL_PUT_ERROR(EC, ec_GFp_simple_point2oct, ERR_R_INTERNAL_ERROR);
goto err;
}
i += field_len;
if (form == POINT_CONVERSION_UNCOMPRESSED ||
form == POINT_CONVERSION_HYBRID) {
skip = field_len - BN_num_bytes(y);
if (skip > field_len) {
if (!BN_bn2bin_padded(buf + i, field_len, y)) {
OPENSSL_PUT_ERROR(EC, ec_GFp_simple_point2oct, ERR_R_INTERNAL_ERROR);
goto err;
}
while (skip > 0) {
buf[i++] = 0;
skip--;
}
skip = BN_bn2bin(y, buf + i);
i += skip;
i += field_len;
}
if (i != ret) {
@@ -177,17 +164,21 @@ static size_t ec_GFp_simple_point2oct(const EC_GROUP *group,
}
}
if (used_ctx)
if (used_ctx) {
BN_CTX_end(ctx);
if (new_ctx != NULL)
}
if (new_ctx != NULL) {
BN_CTX_free(new_ctx);
}
return ret;
err:
if (used_ctx)
if (used_ctx) {
BN_CTX_end(ctx);
if (new_ctx != NULL)
}
if (new_ctx != NULL) {
BN_CTX_free(new_ctx);
}
return 0;
}
crypto/ecdh/ecdh.c
+3 -9
View File
@@ -81,7 +81,7 @@ int ECDH_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
const BIGNUM *priv;
const EC_GROUP *group;
int ret = -1;
size_t buflen, len;
size_t buflen;
uint8_t *buf = NULL;
if ((ctx = BN_CTX_new()) == NULL) {
@@ -116,20 +116,14 @@ int ECDH_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
}
buflen = (EC_GROUP_get_degree(group) + 7) / 8;
len = BN_num_bytes(x);
if (len > buflen) {
OPENSSL_PUT_ERROR(ECDH, ECDH_compute_key, ERR_R_INTERNAL_ERROR);
goto err;
}
buf = OPENSSL_malloc(buflen);
if (buf == NULL) {
OPENSSL_PUT_ERROR(ECDH, ECDH_compute_key, ERR_R_MALLOC_FAILURE);
goto err;
}
memset(buf, 0, buflen - len);
if (len != (size_t)BN_bn2bin(x, buf + buflen - len)) {
OPENSSL_PUT_ERROR(ECDH, ECDH_compute_key, ERR_R_BN_LIB);
if (!BN_bn2bin_padded(buf, buflen, x)) {
OPENSSL_PUT_ERROR(ECDH, ECDH_compute_key, ERR_R_INTERNAL_ERROR);
goto err;
}
crypto/ecdsa/ecdsa_test.c
+5 -4
View File
@@ -217,14 +217,15 @@ int test_builtin(BIO *out) {
goto builtin_err;
}
buf_len = 2 * bn_len;
raw_buf = OPENSSL_malloc(buf_len);
raw_buf = OPENSSL_malloc(2 * bn_len);
if (raw_buf == NULL) {
goto builtin_err;
}
/* Pad the bignums with leading zeroes. */
memset(raw_buf, 0, buf_len);
BN_bn2bin(ecdsa_sig->r, raw_buf + bn_len - r_len);
BN_bn2bin(ecdsa_sig->s, raw_buf + buf_len - s_len);
if (!BN_bn2bin_padded(raw_buf, bn_len, ecdsa_sig->r) ||
!BN_bn2bin_padded(raw_buf + bn_len, bn_len, ecdsa_sig->s)) {
goto builtin_err;
}
/* Modify a single byte in the buffer. */
offset = raw_buf[10] % buf_len;