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MPI random: add unit tests with a previously nonzero value
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Add unit tests for mbedtls_mpi_fill_random() and mbedtls_mpi_random()
when the resulting MPI object previously had a nonzero value. I wrote
those to catch a bug that I introduced during the development of
mbedtls_mpi_random() (but does not appear in a committed version).

Signed-off-by: Gilles Peskine <[email protected]>
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gilles-peskine-arm committed Apr 9, 2021
1 parent 0f1931a commit 5201c52
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Showing 2 changed files with 86 additions and 25 deletions.
88 changes: 65 additions & 23 deletions tests/suites/test_suite_mpi.data
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Original file line number Diff line number Diff line change
Expand Up @@ -992,46 +992,76 @@ Test bit set (Invalid bit value)
mbedtls_mpi_set_bit:16:"00":5:2:16:"00":MBEDTLS_ERR_MPI_BAD_INPUT_DATA

Fill random: 0 bytes
mpi_fill_random:0:0:0
mpi_fill_random:0:0:0:0

Fill random: 1 byte, good
mpi_fill_random:1:1:0
mpi_fill_random:1:1:0:0

Fill random: 2 bytes, good, no leading zero
mpi_fill_random:2:2:0
mpi_fill_random:2:2:0:0

Fill random: 2 bytes, good, 1 leading zero
mpi_fill_random:2:256:0
mpi_fill_random:2:256:0:0

Fill random: MAX_SIZE - 7, good
mpi_fill_random:MBEDTLS_MPI_MAX_SIZE - 7:MBEDTLS_MPI_MAX_SIZE - 7:0
mpi_fill_random:MBEDTLS_MPI_MAX_SIZE - 7:MBEDTLS_MPI_MAX_SIZE - 7:0:0

Fill random: MAX_SIZE, good
mpi_fill_random:MBEDTLS_MPI_MAX_SIZE:MBEDTLS_MPI_MAX_SIZE:0
mpi_fill_random:MBEDTLS_MPI_MAX_SIZE:MBEDTLS_MPI_MAX_SIZE:0:0

Fill random: 0 bytes, previously small >0
mpi_fill_random:0:0:1:0

Fill random: 0 bytes, previously small <0
mpi_fill_random:0:0:-1:0

Fill random: 0 bytes, previously large >0
mpi_fill_random:0:0:65:0

Fill random: 0 bytes, previously large <0
mpi_fill_random:0:0:-65:0

Fill random: 1 byte, previously small >0
mpi_fill_random:1:1:1:0

Fill random: 1 byte, previously small <0
mpi_fill_random:1:1:-1:0

Fill random: 1 byte, previously large >0
mpi_fill_random:1:1:65:0

Fill random: 1 byte, previously large <0
mpi_fill_random:1:1:-65:0

Fill random: 9 bytes, previously small >0
mpi_fill_random:1:1:1:0

Fill random: 9 bytes, previously small <0
mpi_fill_random:1:1:-1:0

Fill random: 1 byte, RNG failure
mpi_fill_random:1:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:1:0:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

Fill random: 2 bytes, RNG failure after 1 byte
mpi_fill_random:2:1:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:2:1:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

Fill random: 4 bytes, RNG failure after 3 bytes
mpi_fill_random:4:3:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:4:3:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

Fill random: 8 bytes, RNG failure after 7 bytes
mpi_fill_random:8:7:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:8:7:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

Fill random: 16 bytes, RNG failure after 1 bytes
mpi_fill_random:16:1:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:16:1:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

Fill random: 16 bytes, RNG failure after 8 bytes
mpi_fill_random:16:8:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:16:8:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

Fill random: 16 bytes, RNG failure after 15 bytes
mpi_fill_random:16:15:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:16:15:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

Fill random: MAX_SIZE bytes, RNG failure after MAX_SIZE-1 bytes
mpi_fill_random:MBEDTLS_MPI_MAX_SIZE:MBEDTLS_MPI_MAX_SIZE-1:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
mpi_fill_random:MBEDTLS_MPI_MAX_SIZE:MBEDTLS_MPI_MAX_SIZE-1:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

MPI random in range: 1..4
mpi_random_many:1:"04":1000
Expand Down Expand Up @@ -1133,31 +1163,43 @@ MPI random in range: 3..4
mpi_random_many:1:"04":1000

MPI random in range: smaller result
mpi_random_grown:1:"aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbb":1
mpi_random_sizes:1:"aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbb":1:0

MPI random in range: same size result (32-bit limbs)
mpi_random_grown:1:"aaaaaaaaaaaaaaaa":2
mpi_random_sizes:1:"aaaaaaaaaaaaaaaa":2:0

MPI random in range: same size result (64-bit limbs)
mpi_random_grown:1:"aaaaaaaaaaaaaaaa":1
mpi_random_sizes:1:"aaaaaaaaaaaaaaaa":1:0

MPI random in range: larger result
mpi_random_grown:1:"aaaaaaaaaaaaaaaa":3
mpi_random_sizes:1:"aaaaaaaaaaaaaaaa":3:0

MPI random in range: leading 0 limb in upper bound #0
mpi_random_grown:1:"00aaaaaaaaaaaaaaaa":0
mpi_random_sizes:1:"00aaaaaaaaaaaaaaaa":0:0

MPI random in range: leading 0 limb in upper bound #1
mpi_random_grown:1:"00aaaaaaaaaaaaaaaa":1
mpi_random_sizes:1:"00aaaaaaaaaaaaaaaa":1:0

MPI random in range: leading 0 limb in upper bound #2
mpi_random_grown:1:"00aaaaaaaaaaaaaaaa":2
mpi_random_sizes:1:"00aaaaaaaaaaaaaaaa":2:0

MPI random in range: leading 0 limb in upper bound #3
mpi_random_grown:1:"00aaaaaaaaaaaaaaaa":3
mpi_random_sizes:1:"00aaaaaaaaaaaaaaaa":3:0

MPI random in range: leading 0 limb in upper bound #4
mpi_random_grown:1:"00aaaaaaaaaaaaaaaa":4
mpi_random_sizes:1:"00aaaaaaaaaaaaaaaa":4:0

MPI random in range: previously small >0
mpi_random_sizes:1:"1234567890":4:1

MPI random in range: previously small <0
mpi_random_sizes:1:"1234567890":4:-1

MPI random in range: previously large >0
mpi_random_sizes:1:"1234":4:65

MPI random in range: previously large <0
mpi_random_sizes:1:"1234":4:-65

MPI random bad arguments: min < 0
mpi_random_fail:-1:"04":MBEDTLS_ERR_MPI_BAD_INPUT_DATA
Expand Down
23 changes: 21 additions & 2 deletions tests/suites/test_suite_mpi.function
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1400,13 +1400,23 @@ exit:
/* END_CASE */

/* BEGIN_CASE */
void mpi_fill_random( int wanted_bytes, int rng_bytes, int expected_ret )
void mpi_fill_random( int wanted_bytes, int rng_bytes,
int before, int expected_ret )
{
mbedtls_mpi X;
int ret;
size_t bytes_left = rng_bytes;
mbedtls_mpi_init( &X );

if( before != 0 )
{
/* Set X to sign(before) * 2^(|before|-1) */
TEST_ASSERT( mbedtls_mpi_lset( &X, before > 0 ? 1 : -1 ) == 0 );
if( before < 0 )
before = - before;
TEST_ASSERT( mbedtls_mpi_shift_l( &X, before - 1 ) == 0 );
}

ret = mbedtls_mpi_fill_random( &X, wanted_bytes,
f_rng_bytes_left, &bytes_left );
TEST_ASSERT( ret == expected_ret );
Expand Down Expand Up @@ -1538,14 +1548,23 @@ exit:
/* END_CASE */

/* BEGIN_CASE */
void mpi_random_grown( int min, data_t *bound_bytes, int nlimbs )
void mpi_random_sizes( int min, data_t *bound_bytes, int nlimbs, int before )
{
mbedtls_mpi upper_bound;
mbedtls_mpi result;

mbedtls_mpi_init( &upper_bound );
mbedtls_mpi_init( &result );

if( before != 0 )
{
/* Set result to sign(before) * 2^(|before|-1) */
TEST_ASSERT( mbedtls_mpi_lset( &result, before > 0 ? 1 : -1 ) == 0 );
if( before < 0 )
before = - before;
TEST_ASSERT( mbedtls_mpi_shift_l( &result, before - 1 ) == 0 );
}

TEST_EQUAL( 0, mbedtls_mpi_grow( &result, nlimbs ) );
TEST_EQUAL( 0, mbedtls_mpi_read_binary( &upper_bound,
bound_bytes->x, bound_bytes->len ) );
Expand Down

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