static int asn1_ex_i2c()

in crypto/asn1/tasn_enc.c [555:697]

• 110 lines of code
• 48 McCabe index (conditional complexity)

static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *out_omit,
                       int *putype, const ASN1_ITEM *it) {
  ASN1_BOOLEAN *tbool = NULL;
  ASN1_STRING *strtmp;
  ASN1_OBJECT *otmp;
  int utype;
  const unsigned char *cont;
  unsigned char c;
  int len;

  // Historically, |it->funcs| for primitive types contained an
  // |ASN1_PRIMITIVE_FUNCS| table of callbacks.
  assert(it->funcs == NULL);

  *out_omit = 0;

  // Should type be omitted?
  if ((it->itype != ASN1_ITYPE_PRIMITIVE) || (it->utype != V_ASN1_BOOLEAN)) {
    if (!*pval) {
      *out_omit = 1;
      return 0;
    }
  }

  if (it->itype == ASN1_ITYPE_MSTRING) {
    // If MSTRING type set the underlying type
    strtmp = (ASN1_STRING *)*pval;
    utype = strtmp->type;
    if (utype < 0 && utype != V_ASN1_OTHER) {
      // MSTRINGs can have type -1 when default-constructed.
      OPENSSL_PUT_ERROR(ASN1, ASN1_R_WRONG_TYPE);
      return -1;
    }
    // Negative INTEGER and ENUMERATED values use |ASN1_STRING| type values
    // that do not match their corresponding utype values. INTEGERs cannot
    // participate in MSTRING types, but ENUMERATEDs can.
    //
    // TODO(davidben): Is this a bug? Although arguably one of the MSTRING
    // types should contain more values, rather than less. See
    // https://crbug.com/boringssl/412. But it is not possible to fit all
    // possible ANY values into an |ASN1_STRING|, so matching the spec here
    // is somewhat hopeless.
    if (utype == V_ASN1_NEG_INTEGER) {
      utype = V_ASN1_INTEGER;
    } else if (utype == V_ASN1_NEG_ENUMERATED) {
      utype = V_ASN1_ENUMERATED;
    }
    *putype = utype;
  } else if (it->utype == V_ASN1_ANY) {
    // If ANY set type and pointer to value
    ASN1_TYPE *typ;
    typ = (ASN1_TYPE *)*pval;
    utype = typ->type;
    if (utype < 0 && utype != V_ASN1_OTHER) {
      // |ASN1_TYPE|s can have type -1 when default-constructed.
      OPENSSL_PUT_ERROR(ASN1, ASN1_R_WRONG_TYPE);
      return -1;
    }
    *putype = utype;
    pval = &typ->value.asn1_value;
  } else {
    utype = *putype;
  }

  switch (utype) {
    case V_ASN1_OBJECT:
      otmp = (ASN1_OBJECT *)*pval;
      cont = otmp->data;
      len = otmp->length;
      if (len == 0) {
        // Some |ASN1_OBJECT|s do not have OIDs and cannot be serialized.
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_ILLEGAL_OBJECT);
        return -1;
      }
      break;

    case V_ASN1_NULL:
      cont = NULL;
      len = 0;
      break;

    case V_ASN1_BOOLEAN:
      tbool = (ASN1_BOOLEAN *)pval;
      if (*tbool == ASN1_BOOLEAN_NONE) {
        *out_omit = 1;
        return 0;
      }
      if (it->utype != V_ASN1_ANY) {
        // Default handling if value == size field then omit
        if ((*tbool && (it->size > 0)) || (!*tbool && !it->size)) {
          *out_omit = 1;
          return 0;
        }
      }
      c = *tbool ? 0xff : 0x00;
      cont = &c;
      len = 1;
      break;

    case V_ASN1_BIT_STRING: {
      int ret =
          i2c_ASN1_BIT_STRING((ASN1_BIT_STRING *)*pval, cout ? &cout : NULL);
      // |i2c_ASN1_BIT_STRING| returns zero on error instead of -1.
      return ret <= 0 ? -1 : ret;
    }

    case V_ASN1_INTEGER:
    case V_ASN1_ENUMERATED: {
      // |i2c_ASN1_INTEGER| also handles ENUMERATED.
      int ret = i2c_ASN1_INTEGER((ASN1_INTEGER *)*pval, cout ? &cout : NULL);
      // |i2c_ASN1_INTEGER| returns zero on error instead of -1.
      return ret <= 0 ? -1 : ret;
    }

    case V_ASN1_OCTET_STRING:
    case V_ASN1_NUMERICSTRING:
    case V_ASN1_PRINTABLESTRING:
    case V_ASN1_T61STRING:
    case V_ASN1_VIDEOTEXSTRING:
    case V_ASN1_IA5STRING:
    case V_ASN1_UTCTIME:
    case V_ASN1_GENERALIZEDTIME:
    case V_ASN1_GRAPHICSTRING:
    case V_ASN1_VISIBLESTRING:
    case V_ASN1_GENERALSTRING:
    case V_ASN1_UNIVERSALSTRING:
    case V_ASN1_BMPSTRING:
    case V_ASN1_UTF8STRING:
    case V_ASN1_SEQUENCE:
    case V_ASN1_SET:
    default:
      // All based on ASN1_STRING and handled the same
      strtmp = (ASN1_STRING *)*pval;
      cont = strtmp->data;
      len = strtmp->length;

      break;
  }
  if (cout && len) {
    OPENSSL_memcpy(cout, cont, len);
  }
  return len;
}