commit 9d6a535ba113ebf839f551c1bdaff7d3df50df68
author Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Mon Nov 25 13:06:05 2019 +0100
committer Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Tue Nov 26 12:54:06 2019 +0100
tree 17625fedd962dcbf8a0a81d705e0cc0e597fafed
parent 4d6186beb0bca06096be6424daa2c618fb787c30

Return and propagate UECC_FAULT_DETECTED

This commit first changes the return convention of EccPoint_mult_safer() so
that it properly reports when faults are detected. Then all functions that
call it need to be changed to (1) follow the same return convention and (2)
properly propagate UECC_FAULT_DETECTED when it occurs.

Here's the reverse call graph from EccPoint_mult_safer() to the rest of the
library (where return values are translated to the MBEDTLS_ERR_ space) and test
functions (where expected return values are asserted explicitly).

EccPoint_mult_safer()
    EccPoint_compute_public_key()
        uECC_compute_public_key()
            pkparse.c
            tests/suites/test_suite_pkparse.function
        uECC_make_key_with_d()
        uECC_make_key()
            ssl_cli.c
            ssl_srv.c
            tests/suites/test_suite_pk.function
            tests/suites/test_suite_tinycrypt.function
    uECC_shared_secret()
        ssl_tls.c
        tests/suites/test_suite_tinycrypt.function
    uECC_sign_with_k()
        uECC_sign()
            pk.c
            tests/suites/test_suite_tinycrypt.function

Note: in uECC_sign_with_k() a test for uECC_vli_isZero(p) is suppressed
because it is redundant with a more thorough test (point validity) done at the
end of EccPoint_mult_safer(). This redundancy was introduced in a previous
commit but not noticed earlier.

tests/suites/test_suite_tinycrypt.function

diff --git a/tests/suites/test_suite_tinycrypt.function b/tests/suites/test_suite_tinycrypt.function
index 3e41720..3247e05 100644
--- a/tests/suites/test_suite_tinycrypt.function
+++ b/tests/suites/test_suite_tinycrypt.function
@@ -23,13 +23,13 @@
 
     uECC_set_rng( &uecc_rng_wrapper );
 
-    TEST_ASSERT( uECC_make_key( public1, private1 ) != 0 );
+    TEST_ASSERT( uECC_make_key( public1, private1 ) == UECC_SUCCESS );
 
-    TEST_ASSERT( uECC_make_key( public2, private2 ) != 0 );
+    TEST_ASSERT( uECC_make_key( public2, private2 ) == UECC_SUCCESS );
 
-    TEST_ASSERT( uECC_shared_secret( public2, private1, secret1 ) != 0 );
+    TEST_ASSERT( uECC_shared_secret( public2, private1, secret1 ) == UECC_SUCCESS );
 
-    TEST_ASSERT( uECC_shared_secret( public1, private2, secret2 ) != 0 );
+    TEST_ASSERT( uECC_shared_secret( public1, private2, secret2 ) == UECC_SUCCESS );
 
     TEST_ASSERT( memcmp( secret1, secret2, sizeof( secret1 ) ) == 0 );
 }
@@ -47,9 +47,9 @@
 
     TEST_ASSERT( rnd_std_rand( NULL, hash, NUM_ECC_BYTES ) == 0 );
 
-    TEST_ASSERT( uECC_make_key( public, private ) != 0 );
+    TEST_ASSERT( uECC_make_key( public, private ) == UECC_SUCCESS );
 
-    TEST_ASSERT( uECC_sign( private, hash, sizeof( hash ), sig ) != 0 );
+    TEST_ASSERT( uECC_sign( private, hash, sizeof( hash ), sig ) == UECC_SUCCESS );
 
     TEST_ASSERT( uECC_verify( public, hash, sizeof( hash ), sig ) == UECC_SUCCESS );
 }
@@ -71,9 +71,9 @@
     memcpy( public2 + NUM_ECC_BYTES, yB_str->x, yB_str->len );
 
     // Compute shared secrets and compare to test vector secret
-    TEST_ASSERT( uECC_shared_secret( public2, private1->x, secret1 ) != 0 );
+    TEST_ASSERT( uECC_shared_secret( public2, private1->x, secret1 ) == UECC_SUCCESS );
 
-    TEST_ASSERT( uECC_shared_secret( public1, private2->x, secret2 ) != 0 );
+    TEST_ASSERT( uECC_shared_secret( public1, private2->x, secret2 ) == UECC_SUCCESS );
 
     TEST_ASSERT( memcmp( secret1, secret2, sizeof( secret1 ) ) == 0 );
     TEST_ASSERT( memcmp( secret1, z_str->x, sizeof( secret1 ) ) == 0 );