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Implemented get_byte() method for mgf1_bitspender class

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The new get_byte() method returns a pseudo-random byte at a time.
Changed the get_bits() interface to the same interface as get_byte().
Updated the mgf1 unit-tests accordingly.
This commit is contained in:
Andreas Steffen
2014-11-29 14:51:16 +01:00
parent 5f7a9ea9c3
commit 72bb7eec9c
4 changed files with 78 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libstrongswan/crypto/mgf1/mgf1_bitspender.c
+47 -11
View File
@@ -62,19 +62,30 @@ struct private_mgf1_bitspender_t {
* Number of available bits
*/
int bits_left;
/**
* Byte storage (accomodates up to 4 bytes)
*/
uint8_t bytes[4];
/**
* Number of available bytes
*/
int bytes_left;
};
METHOD(mgf1_bitspender_t, get_bits, uint32_t,
private_mgf1_bitspender_t *this, int bits_needed)
METHOD(mgf1_bitspender_t, get_bits, bool,
private_mgf1_bitspender_t *this, int bits_needed, uint32_t *bits)
{
uint32_t bits = 0x00000000;
int bits_now;
if (bits_needed > 31)
if (bits_needed > 32)
{
/* too many bits requested */
return MGF1_BITSPENDER_ERROR;
return FALSE;
}
*bits = 0x00000000;
while (bits_needed)
{
@@ -87,7 +98,7 @@ METHOD(mgf1_bitspender_t, get_bits, uint32_t,
this->octets))
{
/* no block available */
return MGF1_BITSPENDER_ERROR;
return FALSE;
}
this->octets_left = this->hash_len;
this->octets_count += this->hash_len;
@@ -102,22 +113,46 @@ METHOD(mgf1_bitspender_t, get_bits, uint32_t,
bits_now = this->bits_left;
this->bits_left = 0;
bits_needed -= bits_now;
bits <<= bits_now;
bits |= this->bits;
*bits <<= bits_now;
*bits |= this->bits;
}
else
{
bits_now = bits_needed;
this->bits_left -= bits_needed;
bits_needed = 0;
bits <<= bits_now;
bits |= this->bits >> this->bits_left;
*bits <<= bits_now;
*bits |= this->bits >> this->bits_left;
this->bits &= 0xffffffff >> (32 - this->bits_left);
}
}
return bits;
return TRUE;
}
METHOD(mgf1_bitspender_t, get_byte, bool,
private_mgf1_bitspender_t *this, uint8_t *byte)
{
if (this->bytes_left == 0)
{
if (this->octets_left == 0)
{
/* get another block from MGF1 */
if (!this->mgf1->get_mask(this->mgf1, this->hash_len, this->octets))
{
/* no block available */
return FALSE;
}
this->octets_left = this->hash_len;
this->octets_count += this->hash_len;
}
memcpy(this->bytes, this->octets + this->hash_len - this->octets_left, 4);
this->bytes_left = 4;
this->octets_left -= 4;
}
*byte = this->bytes[4 - this->bytes_left--];
return TRUE;
}
METHOD(mgf1_bitspender_t, destroy, void,
private_mgf1_bitspender_t *this)
@@ -148,6 +183,7 @@ mgf1_bitspender_t *mgf1_bitspender_create(hash_algorithm_t alg, chunk_t seed,
INIT(this,
.public = {
.get_bits = _get_bits,
.get_byte = _get_byte,
.destroy = _destroy,
},
.mgf1 = mgf1,
src/libstrongswan/crypto/mgf1/mgf1_bitspender.h
+14 -7
View File
@@ -15,7 +15,7 @@
/**
* @defgroup mgf1_bitspender mgf1_bitspender
* @{ @ingroup bliss_p
* @{ @ingroup mgf1_p
*/
#ifndef MGF1_BITSPENDER_H_
@@ -26,20 +26,27 @@
typedef struct mgf1_bitspender_t mgf1_bitspender_t;
#define MGF1_BITSPENDER_ERROR 0xffffffff
/**
* Generates a given number of pseudo-random bits at a time using MFG1
* Generates a given number of pseudo-random bits at a time using MGF1
*/
struct mgf1_bitspender_t {
/**
* Get pseudo-random bits
*
* @param bits_needed Number of needed bits (1..31)
* @result Return between 1 and 31 pseudo-random bits
* @param bits_needed Number of needed bits (1..32)
* @param bits Pseudo-random bits
* @result FALSE if internal MGF1 error occurred
*/
uint32_t (*get_bits)(mgf1_bitspender_t *this, int bits_needed);
bool (*get_bits)(mgf1_bitspender_t *this, int bits_needed, uint32_t *bits);
/**
* Get a pseudo-random byte
*
* @param byte Pseudo-random byte
* @result FALSE if internal MGF1 error occurred
*/
bool (*get_byte)(mgf1_bitspender_t *this, uint8_t *byte);
/**
* Destroy mgf1_bitspender_t object
src/libstrongswan/plugins/ntru/ntru_poly.c
+1 -2
View File
@@ -323,8 +323,7 @@ ntru_poly_t *ntru_poly_create_from_seed(hash_algorithm_t alg, chunk_t seed,
/* generate a random candidate index with a size of c_bits */
do
{
index = bitspender->get_bits(bitspender, c_bits);
if (index == MGF1_BITSPENDER_ERROR)
if (!bitspender->get_bits(bitspender, c_bits, &index))
{
bitspender->destroy(bitspender);
destroy(this);
src/libstrongswan/tests/suites/test_mgf1.c
+16 -6
View File
@@ -27,7 +27,7 @@ typedef struct {
chunk_t seed;
chunk_t hashed_seed;
chunk_t mask;
uint32_t bits[15];
uint32_t bits[20];
} mgf1_test_t;
/**
@@ -70,7 +70,8 @@ mgf1_test_t mgf1_tests[] = {
0x4D, 0x29, 0x0B, 0xCE, 0xA6, 0x21, 0xB5, 0x5C,
0x71, 0x66, 0x2F, 0x70, 0x35, 0xD8, 0x8A, 0x92,
0x33, 0xF0, 0x16, 0xD4, 0x0E, 0x43, 0x8A, 0x14),
{ 0, 0, 0, 4, 1, 1, 46, 103, 38, 411, 848, 57, 3540, 4058, 12403 },
{ 0, 0, 0, 4, 1, 1, 46, 103, 38, 411, 848, 57, 3540, 4058, 12403,
0x63, 0x2B, 0xC9, 0x17, 0x56 },
},
{ HASH_SHA256, 32, 64, 32, 33, 40,
chunk_from_chars(
@@ -119,7 +120,8 @@ mgf1_test_t mgf1_tests[] = {
0x2B, 0x3C, 0x91, 0x3A, 0x32, 0xF8, 0xB2, 0xC6,
0x44, 0x4D, 0xCD, 0xB6, 0x54, 0x5F, 0x81, 0x95,
0x59, 0xA1, 0xE5, 0x4E, 0xA5, 0x0A, 0x4A, 0x42),
{ 0, 1, 3, 4, 4, 12, 32, 36, 253, 331, 2, 1640, 503, 6924, 580 }
{ 0, 1, 3, 4, 4, 12, 32, 36, 253, 331, 2, 1640, 503, 6924, 580,
0xCB, 0x35, 0x3C, 0xDC, 0xAD }
}
};
@@ -192,6 +194,7 @@ START_TEST(mgf1_test_bitspender)
{
mgf1_bitspender_t *bitspender;
uint32_t bits;
uint8_t byte;
int j;
bitspender = mgf1_bitspender_create(HASH_UNKNOWN,
@@ -204,13 +207,20 @@ START_TEST(mgf1_test_bitspender)
for (j = 0; j < 15; j++)
{
bits = bitspender->get_bits(bitspender, j);
ck_assert(bitspender->get_bits(bitspender, j, &bits));
DBG1(DBG_LIB, "bits[%d] = %u, bits = %u", j, mgf1_tests[_i].bits[j],
bits);
ck_assert(bits == mgf1_tests[_i].bits[j]);
}
bits = bitspender->get_bits(bitspender, 32);
ck_assert(bits == MGF1_BITSPENDER_ERROR);
ck_assert(!bitspender->get_bits(bitspender, 33, &bits));
for (j = 15; j < 20; j++)
{
ck_assert(bitspender->get_byte(bitspender, &byte));
DBG1(DBG_LIB, "bits[%d] = 0x%02x, byte = 0x%02x", j,
mgf1_tests[_i].bits[j], byte);
ck_assert(byte == mgf1_tests[_i].bits[j]);
}
bitspender->destroy(bitspender);
}