From d8d19de1c7e489c252fad84e8def9563477fa2b3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Manuel=20P=C3=A9gouri=C3=A9-Gonnard?= Date: Wed, 20 Apr 2022 10:34:22 +0200 Subject: [PATCH] Expand negative coverage of ECDSA verification MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Motivated by CVE-2022-21449, to which we're not vulnerable, but we didn't have a test for it. Now we do. Signed-off-by: Manuel Pégourié-Gonnard --- tests/suites/test_suite_ecdsa.function | 74 ++++++++++++++++++++++---- 1 file changed, 63 insertions(+), 11 deletions(-) diff --git a/tests/suites/test_suite_ecdsa.function b/tests/suites/test_suite_ecdsa.function index 4496812156..e7aeb074ef 100644 --- a/tests/suites/test_suite_ecdsa.function +++ b/tests/suites/test_suite_ecdsa.function @@ -117,20 +117,72 @@ void ecdsa_prim_test_vectors( int id, char * d_str, char * xQ_str, if ( result == 0) { - TEST_ASSERT( mbedtls_mpi_cmp_mpi( &r, &r_check ) == 0 ); - TEST_ASSERT( mbedtls_mpi_cmp_mpi( &s, &s_check ) == 0 ); + /* save correct values; we'll generate incorrect ones below */ + TEST_EQUAL( mbedtls_mpi_cmp_mpi( &r, &r_check ), 0 ); + TEST_EQUAL( mbedtls_mpi_cmp_mpi( &s, &s_check ), 0 ); - TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, &r_check, &s_check ) == 0 ); + /* Valid signature */ + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, + &Q, &r_check, &s_check ), 0 ); - TEST_ASSERT( mbedtls_mpi_sub_int( &r, &r, 1 ) == 0 ); - TEST_ASSERT( mbedtls_mpi_add_int( &s, &s, 1 ) == 0 ); + /* Invalid signature: wrong public key (G instead of Q) */ + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, + &grp.G, &r_check, &s_check ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); - TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, - &Q, &r, &s_check ) == MBEDTLS_ERR_ECP_VERIFY_FAILED ); - TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, - &Q, &r_check, &s ) == MBEDTLS_ERR_ECP_VERIFY_FAILED ); - TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, - &grp.G, &r_check, &s_check ) == MBEDTLS_ERR_ECP_VERIFY_FAILED ); + /* Invalid signatures: r or s or both one off */ + TEST_EQUAL( mbedtls_mpi_sub_int( &r, &r, 1 ), 0 ); + TEST_EQUAL( mbedtls_mpi_add_int( &s, &s, 1 ), 0 ); + + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s_check ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r_check, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + + /* Invalid signatures: r, s or both (CVE-2022-21449) are zero */ + TEST_EQUAL( mbedtls_mpi_lset( &r, 0 ), 0 ); + TEST_EQUAL( mbedtls_mpi_lset( &s, 0 ), 0 ); + + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s_check ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r_check, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + + /* Invalid signatures: r, s or both are negative */ + TEST_EQUAL( mbedtls_mpi_lset( &r, -1 ), 0 ); + TEST_EQUAL( mbedtls_mpi_lset( &s, -1 ), 0 ); + + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s_check ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r_check, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + + /* Invalid signatures: r, s or both are == N */ + TEST_EQUAL( mbedtls_mpi_copy( &r, &grp.N ), 0 ); + TEST_EQUAL( mbedtls_mpi_copy( &s, &grp.N ), 0 ); + + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s_check ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r_check, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + + /* Invalid signatures: r or s or both are > N */ + TEST_EQUAL( mbedtls_mpi_add_int( &r, &grp.N, 1 ), 0 ); + TEST_EQUAL( mbedtls_mpi_add_int( &s, &grp.N, 1 ), 0 ); + + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s_check ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r_check, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); + TEST_EQUAL( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, + &r, &s ), MBEDTLS_ERR_ECP_VERIFY_FAILED ); } exit: