New BN functions.

Add new function BN_bn2binpad() which checks the length of the output
buffer and pads the result with zeroes if necessary.

New functions BN_bn2lebinpad() and BN_lebin2bn() which use little endian
format.

Reviewed-by: Rich Salz <rsalz@openssl.org>

1 files changed, 18 insertions, 2 deletions

diff --git a/doc/crypto/BN_bn2bin.pod b/doc/crypto/BN_bn2bin.pod
index dd1007d2ce..cbd5d340e1 100644
--- a/doc/crypto/BN_bn2bin.pod
+++ b/doc/crypto/BN_bn2bin.pod
@@ -2,16 +2,21 @@
 
 =head1 NAME
 
-BN_bn2bin, BN_bin2bn, BN_bn2hex, BN_bn2dec, BN_hex2bn, BN_dec2bn,
-BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn - format conversions
+BN_bn2bin, BN_bin2bn, BN_bn2lebinpad, BN_lebin2bn, BN_bn2hex, BN_bn2dec,
+BN_hex2bn, BN_dec2bn, BN_print, BN_print_fp, BN_bn2mpi,
+BN_mpi2bn - format conversions
 
 =head1 SYNOPSIS
 
  #include <openssl/bn.h>
 
  int BN_bn2bin(const BIGNUM *a, unsigned char *to);
+ int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen);
  BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret);
 
+ int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen);
+ BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret);
+
  char *BN_bn2hex(const BIGNUM *a);
  char *BN_bn2dec(const BIGNUM *a);
  int BN_hex2bn(BIGNUM **a, const char *str);
@@ -29,10 +34,18 @@ BN_bn2bin() converts the absolute value of B<a> into big-endian form
 and stores it at B<to>. B<to> must point to BN_num_bytes(B<a>) bytes of
 memory.
 
+BN_bn2binpad() also converts the absolute value of B<a> into big-endian form
+and stores it at B<to>. B<tolen> indicates the length of the output buffer
+B<to>. The result is padded with zeroes if necessary. If B<tolen> is less than
+BN_num_bytes(B<a>) an error is returned.
+
 BN_bin2bn() converts the positive integer in big-endian form of length
 B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If B<ret> is
 NULL, a new B<BIGNUM> is created.
 
+BN_bn2lebinpad() and BN_bin2lbn() are identical to BN_bn2binpad() and
+BN_bin2bn() except the buffer is in little-endian format.
+
 BN_bn2hex() and BN_bn2dec() return printable strings containing the
 hexadecimal and decimal encoding of B<a> respectively. For negative
 numbers, the string is prefaced with a leading '-'. The string must be
@@ -67,6 +80,9 @@ if B<ret> is NULL.
 BN_bn2bin() returns the length of the big-endian number placed at B<to>.
 BN_bin2bn() returns the B<BIGNUM>, NULL on error.
 
+BN_bn2binpad() returns the number of bytes written or -1 if the supplied
+buffer is too small.
+
 BN_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL
 on error. BN_hex2bn() and BN_dec2bn() return the number's length in
 hexadecimal or decimal digits, and 0 on error.