diff options
| -rw-r--r-- | mpi/mpi-pow.c | 4 | ||||
| -rw-r--r-- | tests/mpitests.c | 19 |
2 files changed, 21 insertions, 2 deletions
diff --git a/mpi/mpi-pow.c b/mpi/mpi-pow.c index 469c382a..4bf0233a 100644 --- a/mpi/mpi-pow.c +++ b/mpi/mpi-pow.c @@ -177,7 +177,7 @@ gcry_mpi_powm (gcry_mpi_t res, } MPN_COPY ( rp, bp, bsize ); rsize = bsize; - rsign = bsign; + rsign = 0; /* Main processing. */ { @@ -192,7 +192,7 @@ gcry_mpi_powm (gcry_mpi_t res, xp = xp_marker = mpi_alloc_limb_space( 2 * (msize + 1), msec ); memset( &karactx, 0, sizeof karactx ); - negative_result = (ep[0] & 1) && base->sign; + negative_result = (ep[0] & 1) && bsign; i = esize - 1; e = ep[i]; diff --git a/tests/mpitests.c b/tests/mpitests.c index 1c4edb66..9d1206e5 100644 --- a/tests/mpitests.c +++ b/tests/mpitests.c @@ -520,6 +520,25 @@ test_powm (void) if (gcry_mpi_cmp (res, base)) die ("test_powm failed at %d\n", __LINE__); + /* Check for a case: base is negative and expo is even. */ + gcry_mpi_set_ui (base, b_int); + gcry_mpi_neg (base, base); + gcry_mpi_set_ui (exp, e_int * 2); + gcry_mpi_set_ui(mod, m_int); + gcry_mpi_powm (res, base, exp, mod); + /* Result should be positive and it's 7 = (-17)^6 mod 19. */ + if (gcry_mpi_is_neg (res) || gcry_mpi_cmp_ui (res, 7)) + { + if (verbose) + { + fprintf (stderr, "is_neg: %d\n", gcry_mpi_is_neg (res)); + fprintf (stderr, "mpi: "); + gcry_mpi_dump (res); + putc ('\n', stderr); + } + die ("test_powm failed for negative base at %d\n", __LINE__); + } + gcry_mpi_release (base); gcry_mpi_release (exp); gcry_mpi_release (mod); |