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.
diff --git a/include/tinycrypt/ecc.h b/include/tinycrypt/ecc.h
index b199589..ebd16d6 100644
--- a/include/tinycrypt/ecc.h
+++ b/include/tinycrypt/ecc.h
@@ -217,7 +217,7 @@
* @param private_key IN -- The private key to compute the public key for
* @param public_key OUT -- Will be filled in with the corresponding public key
* @param curve
- * @return Returns 1 if key was computed successfully, 0 if an error occurred.
+ * @return UECC_SUCCESS or UECC_FAILURE or UECC_FAULT_DETECTED
*/
int uECC_compute_public_key(const uint8_t *private_key,
uint8_t *public_key);
@@ -228,6 +228,7 @@
* @param result OUT -- public-key
* @param private_key IN -- private-key
* @param curve IN -- elliptic curve
+ * @return UECC_SUCCESS or UECC_FAILURE or UECC_FAULT_DETECTED
*/
uECC_word_t EccPoint_compute_public_key(uECC_word_t *result,
uECC_word_t *private_key);
@@ -241,6 +242,7 @@
* @param result OUT -- returns scalar*point
* @param point IN -- elliptic curve point
* @param scalar IN -- scalar
+ * @return UECC_SUCCESS or UECC_FAILURE or UECC_FAULT_DETECTED
*/
int EccPoint_mult_safer(uECC_word_t * result, const uECC_word_t * point,
const uECC_word_t * scalar);