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Uniform BN_bn2binpad() and BN_bn2lebinpad() implementations

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Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/9511)

(cherry picked from commit 1b338abe3abb8c73f004c34d4b8a9272b89dfd5d)
This commit is contained in:
Nicola Tuveri 2019-09-06 00:18:36 +03:00
parent b9a380f78c
commit 2432e1291d
1 changed files with 17 additions and 20 deletions
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37
crypto/bn/bn_lib.c
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@ -458,8 +458,11 @@ BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
return ret;
}
typedef enum {big, little} endianess_t;
/* ignore negative */
static int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
static
int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen, endianess_t endianess)
{
int n;
size_t i, lasti, j, atop, mask;
@ -491,10 +494,17 @@ static int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
lasti = atop - 1;
atop = a->top * BN_BYTES;
for (i = 0, j = 0, to += tolen; j < (size_t)tolen; j++) {
if (endianess == big)
to += tolen; /* start from the end of the buffer */
for (i = 0, j = 0; j < (size_t)tolen; j++) {
unsigned char val;
l = a->d[i / BN_BYTES];
mask = 0 - ((j - atop) >> (8 * sizeof(i) - 1));
*--to = (unsigned char)(l >> (8 * (i % BN_BYTES)) & mask);
val = (unsigned char)(l >> (8 * (i % BN_BYTES)) & mask);
if (endianess == big)
*--to = val;
else
*to++ = val;
i += (i - lasti) >> (8 * sizeof(i) - 1); /* stay on last limb */
}
@ -505,12 +515,12 @@ int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
{
if (tolen < 0)
return -1;
return bn2binpad(a, to, tolen);
return bn2binpad(a, to, tolen, big);
}
int BN_bn2bin(const BIGNUM *a, unsigned char *to)
{
return bn2binpad(a, to, -1);
return bn2binpad(a, to, -1, big);
}
BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret)
@ -562,22 +572,9 @@ BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret)
int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen)
{
int i;
BN_ULONG l;
bn_check_top(a);
i = BN_num_bytes(a);
if (tolen < i)
if (tolen < 0)
return -1;
/* Add trailing zeroes if necessary */
if (tolen > i)
memset(to + i, 0, tolen - i);
to += i;
while (i--) {
l = a->d[i / BN_BYTES];
to--;
*to = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
}
return tolen;
return bn2binpad(a, to, tolen, little);
}
int BN_ucmp(const BIGNUM *a, const BIGNUM *b)