Do not rely on calloc zeroing out allocations

src/eip7594/eip7594.c

@@ -91,6 +91,11 @@ C_KZG_RET compute_cells_and_kzg_proofs(
     ret = poly_lagrange_to_monomial(poly_monomial, poly_lagrange, FIELD_ELEMENTS_PER_BLOB, s);
     if (ret != C_KZG_OK) goto out;
 
+    /* Ensure the upper half of the fields are zero */
+    for (size_t i = FIELD_ELEMENTS_PER_BLOB; i < FIELD_ELEMENTS_PER_EXT_BLOB; i++) {
+        poly_monomial[i] = FR_ZERO;
+    }
+
     if (cells != NULL) {
         /* Allocate space for our data points */
         ret = new_fr_array(&data_fr, FIELD_ELEMENTS_PER_EXT_BLOB);

src/eip7594/recovery.c

@@ -135,6 +135,11 @@ static C_KZG_RET vanishing_polynomial_for_missing_cells(
     );
     if (ret != C_KZG_OK) goto out;
 
+    /* Zero out all the coefficients */
+    for (size_t i = 0; i < FIELD_ELEMENTS_PER_EXT_BLOB; i++) {
+        vanishing_poly[i] = FR_ZERO;
+    }
+
     /*
      * For each root \omega^i in `short_vanishing_poly`, we compute a polynomial that has roots at
      *
@@ -246,10 +251,7 @@ C_KZG_RET recover_cells(
     for (size_t i = 0; i < CELLS_PER_EXT_BLOB; i++) {
         /* Iterate over each cell index and check if we have received it */
         if (!is_in_array(cell_indices, num_cells, i)) {
-            /*
-             * If the cell is missing, bit reverse the index and add it to the
-             * missing array.
-             */
+            /* If the cell is missing, bit reverse the index and add it to the missing array */
             uint32_t brp_i = reverse_bits_limited(CELLS_PER_EXT_BLOB, i);
             missing_cell_indices[len_missing++] = brp_i;
         }