From 212a75004207234fa677f73e71a1c42b541b009e Mon Sep 17 00:00:00 2001 From: Nicola Tuveri Date: Fri, 6 Sep 2019 00:18:36 +0300 Subject: [PATCH] Uniform BN_bn2binpad() and BN_bn2lebinpad() implementations Reviewed-by: Matt Caswell Reviewed-by: Bernd Edlinger (Merged from https://github.com/openssl/openssl/pull/9511) (cherry picked from commit 1b338abe3abb8c73f004c34d4b8a9272b89dfd5d) --- crypto/bn/bn_lib.c | 37 +++++++++++++++++-------------------- 1 file changed, 17 insertions(+), 20 deletions(-) diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c index c882f14029..144653e2b4 100644 --- a/crypto/bn/bn_lib.c +++ b/crypto/bn/bn_lib.c @@ -543,8 +543,11 @@ 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; @@ -576,10 +579,17 @@ 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 */ } @@ -590,12 +600,12 @@ 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) @@ -647,22 +657,9 @@ 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) -- 2.25.1