diff options
| -rw-r--r-- | ChangeLog | 10 | ||||
| -rw-r--r-- | ecc-secp224r1.c | 7 | ||||
| -rw-r--r-- | testsuite/ecc-sqrt-test.c | 40 |
3 files changed, 54 insertions, 3 deletions
@@ -1,3 +1,13 @@ +2021-11-13 Niels Möller <nisse@lysator.liu.se> + + * ecc-secp224r1.c (ecc_secp224r1_sqrt): Fix result for zero + input, which needs handling as a special case in the + Tonelli-Shanks algorithm. + + * testsuite/ecc-sqrt-test.c (test_sqrt_ratio): Check that sqrt(0) + returns 0. + (test_sqrt_ratio): Check that sqrt (0/1) returns 0. + 2021-11-11 Niels Möller <nisse@lysator.liu.se> * eccdata.c (output_curve): Output ecc_sqrt_z and ECC_SQRT_E only diff --git a/ecc-secp224r1.c b/ecc-secp224r1.c index 3d19fde7..bb321298 100644 --- a/ecc-secp224r1.c +++ b/ecc-secp224r1.c @@ -189,10 +189,11 @@ ecc_secp224r1_sqrt (const struct ecc_modulo *p, if (m == r) { - /* No square root. Will always be detected on first round in - the outer loop. */ + /* We get here if there is no square root, or input is zero. + Will always be detected on first round in the outer + loop. */ assert (r == ECC_SQRT_E); - return 0; + return ecc_mod_zero_p (p, xp); } if (m < r - 1) diff --git a/testsuite/ecc-sqrt-test.c b/testsuite/ecc-sqrt-test.c index 69e08aa4..096cbafc 100644 --- a/testsuite/ecc-sqrt-test.c +++ b/testsuite/ecc-sqrt-test.c @@ -87,6 +87,25 @@ test_sqrt (gmp_randstate_t rands, const struct ecc_modulo *m, int use_redc) rp = xalloc_limbs (2*m->size); scratch = xalloc_limbs (m->sqrt_itch); + /* Check behaviour for zero input */ + mpn_zero (up, m->size); + memset (rp, 17, m->size * sizeof(*rp)); + if (!m->sqrt (m, rp, up, scratch)) + { + fprintf (stderr, "m->sqrt returned failure for zero input, bit_size = %d\n", + m->bit_size); + abort(); + } + if (!ecc_mod_zero_p (m, rp)) + { + fprintf (stderr, "m->sqrt failed for zero input (bit size %u):\n", + m->bit_size); + fprintf (stderr, "r = "); + mpn_out_str (stderr, 16, rp, m->size); + fprintf (stderr, " (bad)\n"); + abort (); + } + /* Find a non-square */ for (z = 2; mpz_ui_kronecker (z, p) != -1; z++) ; @@ -176,6 +195,27 @@ test_sqrt_ratio (gmp_randstate_t rands, const struct ecc_modulo *m) rp = xalloc_limbs (2*m->size); scratch = xalloc_limbs (m->sqrt_ratio_itch); + /* Check behaviour for zero input */ + mpn_zero (up, m->size); + mpn_zero (vp, m->size); + vp[0] = 1; + memset (rp, 17, m->size * sizeof(*rp)); + if (!m->sqrt_ratio (m, rp, up, vp, scratch)) + { + fprintf (stderr, "m->sqrt_ratio returned failure for zero input, bit_size = %d\n", + m->bit_size); + abort(); + } + if (!ecc_mod_zero_p (m, rp)) + { + fprintf (stderr, "m->sqrt_ratio failed for zero input (bit size %u):\n", + m->bit_size); + fprintf (stderr, "r = "); + mpn_out_str (stderr, 16, rp, m->size); + fprintf (stderr, " (bad)\n"); + abort (); + } + /* Find a non-square */ for (z = 2; mpz_ui_kronecker (z, p) != -1; z++) ; |