Commit 9018f3ce authored by Rich Salz's avatar Rich Salz
Browse files

Add constant-time 64 



Standardize comments.

Reviewed-by: default avatarAndy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3727)
parent d2916a5b

include/internal/constant_time_locl.h

+35 −22
Original line number Diff line number Diff line
@@ -21,15 +21,12 @@ extern "C" { 
 * The boolean methods return a bitmask of all ones (0xff...f) for true

 * and 0 for false. This is useful for choosing a value based on the result

 * of a conditional in constant time. For example,

 *

 *      if (a < b) {

 *        c = a;

 *      } else {

 *        c = b;

 *      }

 *

 * can be written as

 *

 *      unsigned int lt = constant_time_lt(a, b);

 *      c = constant_time_select(lt, a, b);

 */
@@ -41,35 +38,31 @@ extern "C" { 
 * replace this with something else on odd CPUs.

 */

static ossl_inline unsigned int constant_time_msb(unsigned int a);

/* Convenience method for uint64_t. */

static ossl_inline uint64_t constant_time_msb_64(uint64_t a);



/*

 * Returns 0xff..f if a < b and 0 otherwise.

 */

/* Returns 0xff..f if a < b and 0 otherwise. */

static ossl_inline unsigned int constant_time_lt(unsigned int a,

                                                 unsigned int b);

/* Convenience method for getting an 8-bit mask. */

static ossl_inline unsigned char constant_time_lt_8(unsigned int a,

                                                    unsigned int b);

/* Convenience method for uint64_t. */

static ossl_inline uint64_t constant_time_lt_64(uint64_t a, uint64_t b);



/*

 * Returns 0xff..f if a >= b and 0 otherwise.

 */

/* Returns 0xff..f if a >= b and 0 otherwise. */

static ossl_inline unsigned int constant_time_ge(unsigned int a,

                                                 unsigned int b);

/* Convenience method for getting an 8-bit mask. */

static ossl_inline unsigned char constant_time_ge_8(unsigned int a,

                                                    unsigned int b);



/*

 * Returns 0xff..f if a == 0 and 0 otherwise.

 */

/* Returns 0xff..f if a == 0 and 0 otherwise. */

static ossl_inline unsigned int constant_time_is_zero(unsigned int a);

/* Convenience method for getting an 8-bit mask. */

static ossl_inline unsigned char constant_time_is_zero_8(unsigned int a);



/*

 * Returns 0xff..f if a == b and 0 otherwise.

 */

/* Returns 0xff..f if a == b and 0 otherwise. */

static ossl_inline unsigned int constant_time_eq(unsigned int a,

                                                 unsigned int b);

/* Convenience method for getting an 8-bit mask. */
@@ -94,15 +87,24 @@ static ossl_inline unsigned int constant_time_select(unsigned int mask, 
static ossl_inline unsigned char constant_time_select_8(unsigned char mask,

                                                        unsigned char a,

                                                        unsigned char b);

/* Convenience method for uint64_t. */

static ossl_inline uint64_t constant_time_select_64(uint64_t mask, uint64_t a,

                                                    uint64_t b);

/* Convenience method for signed integers. */

static ossl_inline int constant_time_select_int(unsigned int mask, int a,

                                                int b);





static ossl_inline unsigned int constant_time_msb(unsigned int a)

{

    return 0 - (a >> (sizeof(a) * 8 - 1));

}



static ossl_inline uint64_t constant_time_msb_64(uint64_t a)

{

    return 0 - (a >> 63);

}



static ossl_inline size_t constant_time_msb_s(size_t a)

{

    return 0 - (a >> (sizeof(a) * 8 - 1));
@@ -125,6 +127,11 @@ static ossl_inline unsigned char constant_time_lt_8(unsigned int a, 
    return (unsigned char)(constant_time_lt(a, b));

}



static ossl_inline uint64_t constant_time_lt_64(uint64_t a, uint64_t b)

{

    return constant_time_msb_64(a ^ ((a ^ b) | ((a - b) ^ b)));

}



static ossl_inline unsigned int constant_time_ge(unsigned int a,

                                                 unsigned int b)

{
@@ -227,6 +234,12 @@ static ossl_inline int constant_time_select_int_s(size_t mask, int a, int b) 
                                      (unsigned)(b)));

}



static ossl_inline uint64_t constant_time_select_64(uint64_t mask, uint64_t a,

                                                    uint64_t b)

{

    return (mask & a) | (~mask & b);

}



#ifdef __cplusplus

}

#endif

test/constant_time_test.c

+70 −7
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ static const unsigned char CONSTTIME_TRUE_8 = 0xff; 
static const unsigned char CONSTTIME_FALSE_8 = 0;

static const size_t CONSTTIME_TRUE_S = ~((size_t)0);

static const size_t CONSTTIME_FALSE_S = 0;

static uint64_t CONSTTIME_TRUE_64 = (uint64_t)(~(uint64_t)0);

static uint64_t CONSTTIME_FALSE_64 = 0;



static int test_binary_op(unsigned int (*op) (unsigned int a, unsigned int b),

                          const char *op_name, unsigned int a, unsigned int b,
@@ -56,6 +58,25 @@ static int test_binary_op_s(size_t (*op) (size_t a, size_t b), 
    return 1;

}



static int test_binary_op_64(uint64_t (*op)(uint64_t a, uint64_t b),

                             const char *op_name, uint64_t a, uint64_t b,

                             int is_true)

{

    uint64_t c = op(a, b);



    if (is_true && c != CONSTTIME_TRUE_64) {

        TEST_error("TRUE %s op failed", op_name);

        BIO_printf(bio_err, "a=%jx b=%jx\n", a, b);

        return 0;

    } else if (!is_true && c != CONSTTIME_FALSE_64) {

        TEST_error("FALSE %s op failed", op_name);

        BIO_printf(bio_err, "a=%jx b=%jx\n", a, b);

        return 0;

    }

    return 1;

}





static int test_is_zero(unsigned int a)

{

    if (a == 0 && !TEST_uint_eq(constant_time_is_zero(a), CONSTTIME_TRUE))
@@ -110,6 +131,23 @@ static int test_select_s(unsigned char a, unsigned char b) 
    return 1;

}



static int test_select_64(uint64_t a, uint64_t b)

{

    uint64_t selected = constant_time_select_64(CONSTTIME_TRUE_64, a, b);



    if (selected != a) {

        TEST_error("test_select_64 TRUE failed");

        BIO_printf(bio_err, "a=%jx b=%jx got %jx wanted a\n", a, b, selected);

        return 0;

    }

    selected = constant_time_select_64(CONSTTIME_FALSE_64, a, b);

    if (selected != b) {

        BIO_printf(bio_err, "a=%jx b=%jx got %jx wanted b\n", a, b, selected);

        return 0;

    }

    return 1;

}



static int test_select_int(int a, int b)

{

    if (!TEST_int_eq(constant_time_select_int(CONSTTIME_TRUE, a, b), a))
@@ -146,26 +184,33 @@ static int test_eq_int(int a, int b) 
    return 1;

}



static unsigned int test_values[] =

    { 0, 1, 1024, 12345, 32000, UINT_MAX / 2 - 1,

static unsigned int test_values[] = {

    0, 1, 1024, 12345, 32000, UINT_MAX / 2 - 1,

    UINT_MAX / 2, UINT_MAX / 2 + 1, UINT_MAX - 1,

    UINT_MAX

};



static unsigned char test_values_8[] =

    { 0, 1, 2, 20, 32, 127, 128, 129, 255 };

static unsigned char test_values_8[] = {

    0, 1, 2, 20, 32, 127, 128, 129, 255

};



static int signed_test_values[] = { 0, 1, -1, 1024, -1024, 12345, -12345,

static int signed_test_values[] = {

    0, 1, -1, 1024, -1024, 12345, -12345,

    32000, -32000, INT_MAX, INT_MIN, INT_MAX - 1,

    INT_MIN + 1

};



static size_t test_values_s[] =

    { 0, 1, 1024, 12345, 32000, SIZE_MAX / 2 - 1,

static size_t test_values_s[] = {

    0, 1, 1024, 12345, 32000, SIZE_MAX / 2 - 1,

    SIZE_MAX / 2, SIZE_MAX / 2 + 1, SIZE_MAX - 1,

    SIZE_MAX

};



static uint64_t test_values_64[] = {

    0, 1, 1024, 12345, 32000, 32000000, 32000000001, UINT64_MAX / 2,

    UINT64_MAX / 2 + 1, UINT64_MAX - 1, UINT64_MAX

};



static int test_sizeofs(void)

{

    if (!TEST_uint_eq(OSSL_NELEM(test_values), OSSL_NELEM(test_values_s)))
@@ -264,6 +309,23 @@ static int test_8values(int i) 
    return ret;

}



static int test_64values(int i)

{

    uint64_t g = test_values_64[i];

    int j, ret = 1;



    for (j = i + 1; j < (int)OSSL_NELEM(test_values_64); j++) {

        uint64_t h = test_values_64[j];



        if (!test_binary_op_64(&constant_time_lt_64, "constant_time_lt_64",

                               g, h, g < h)

                || !test_select_64(g, h)) {

            TEST_info("test_64values failed i=%d j=%d", i, j);

            ret = 0;

        }

    }

    return ret;

}



void register_tests(void)

{
@@ -271,4 +333,5 @@ void register_tests(void) 
    ADD_ALL_TESTS(test_binops, OSSL_NELEM(test_values));

    ADD_ALL_TESTS(test_signed, OSSL_NELEM(signed_test_values));

    ADD_ALL_TESTS(test_8values, sizeof(test_values_8));

    ADD_ALL_TESTS(test_64values, sizeof(test_values_64));

}