check return error

Zondax · Dec 7, 2023 · be1e4a6 · be1e4a6
1 parent 2e623f8
commit be1e4a6
Show file tree

Hide file tree

Showing 3 changed files with 12 additions and 7 deletions.
diff --git a/app/src/apdu_handler.c b/app/src/apdu_handler.c
@@ -758,13 +758,17 @@ void handleTest(volatile uint32_t *tx) {
 
   jubjub_extendedpoint p;
   jubjub_fq scal;
-  jubjub_field_frombytes(scal, scalar);
+  if (jubjub_field_frombytes(scal, scalar) != zxerr_ok) {
+    *tx = 0;
+    MEMZERO(point, sizeof(point));
+    THROW(APDU_CODE_OK);
+  }
 
   jubjub_extendedpoint_tobytes(point, JUBJUB_GEN);
-  zxerr_t err = jubjub_extendedpoint_frombytes(&p, point);
+  const zxerr_t err = jubjub_extendedpoint_frombytes(&p, point);
   if (err != zxerr_ok) {
     *tx = 0;
-    MEMZERO(point, 32);
+    MEMZERO(point, sizeof(point));
     THROW(APDU_CODE_OK);
   }
   // MEMCPY(&p, &JUBJUB_GEN, 32);

diff --git a/app/src/jubjub.c b/app/src/jubjub.c
@@ -101,11 +101,12 @@ void u8_cmov(uint8_t *r, uint8_t a, uint8_t bit) {
   *r = *r ^ x;
 }
 
-void jubjub_field_frombytes(jubjub_fq r, const uint8_t *s) {
+zxerr_t jubjub_field_frombytes(jubjub_fq r, const uint8_t *s) {
   MEMZERO(r, sizeof(jubjub_fq));
   MEMCPY(r, s, sizeof(jubjub_fq));
-  cx_math_modm_no_throw(r, JUBJUB_FIELD_BYTES, JUBJUB_FQ_MODULUS_BYTES,
+  const cx_err_t error = cx_math_modm_no_throw(r, JUBJUB_FIELD_BYTES, JUBJUB_FQ_MODULUS_BYTES,
                         JUBJUB_FIELD_BYTES);
+  return error == CX_OK ? zxerr_ok : zxerr_invalid_crypto_settings;
 }
 
 int jubjub_field_iszero(const jubjub_fq r) {
@@ -353,7 +354,7 @@ zxerr_t jubjub_extendedpoint_frombytes(jubjub_extendedpoint *p, uint8_t *s) {
 
   jubjub_fq v, v2, v3, u;
 
-  jubjub_field_frombytes(v, b);
+  CHECK_ZXERR(jubjub_field_frombytes(v, b));
   jubjub_field_square(v2, v);
   jubjub_field_copy(v3, v2);
   jubjub_field_mult(v2, v2, JUBJUB_FQ_EDWARDS_D);

diff --git a/app/src/jubjub.h b/app/src/jubjub.h
@@ -58,6 +58,6 @@ void jubjub_extendedpoint_tobytes(uint8_t *s, jubjub_extendedpoint p);
 
 void jubjub_extendedpoint_scalarmult(jubjub_extendedpoint *r, jubjub_fr scalar);
 
-void jubjub_field_frombytes(jubjub_fq r, const uint8_t *s);
+zxerr_t jubjub_field_frombytes(jubjub_fq r, const uint8_t *s);
 
 zxerr_t jubjub_extendedpoint_frombytes(jubjub_extendedpoint *p, uint8_t *s);