Read binary and add readFile

Signed-off-by: Raul Metsma <raul@metsma.ee>

Author: metsma

lib/libpcsc-cpp/include/pcsc-cpp/pcsc-cpp.hpp

@@ -182,9 +182,9 @@ struct CommandApdu
     constexpr operator const byte_vector&() const { return d; }
 
     /**
-     * A helper function to create a SELECT command APDU.
+     * A helper function to create a SELECT FILE command APDU.
      *
-     * The ISO 7816-4 Section 6.11 SELECT command has the form:
+     * The ISO 7816-4 Section 6.11 SELECT FILE command has the form:
      *   CLA = 0x00
      *   INS = 0xA4
      *   P1  = varies, see below.
@@ -193,6 +193,7 @@ struct CommandApdu
      *
      * The P1 parameter for the SELECT command controls the selection mode,
      * we use the following modes:
+     *   0x02 = Select EF under current DF,
      *   0x04 = Select AID (application identifier),
      *          direct selection by DF (dedicated file, directory) name.
      *   0x08 = Select from MF (master file, root directory).
@@ -203,6 +204,27 @@ struct CommandApdu
         return {0x00, 0xA4, p1, 0x0C, std::move(file)};
     }
 
+    static PCSC_CPP_CONSTEXPR_VECTOR CommandApdu selectEF(byte_type p1, byte_vector file)
+    {
+        return {0x00, 0xA4, p1, 0x04, std::move(file), 0x00};
+    }
+
+    /**
+     * A helper function to create a READ BINARY command APDU.
+     *
+     * The ISO 7816-4 Section 6.1 READ BINARY command has the form:
+     *   CLA = 0x00
+     *   INS = 0xB0
+     *   P1, P2 = if bit8=0 in P1, then P1||P2 is the offset of the first byte to be read in data units from the
+     * beginning of the file.
+     *   Lc and Data field = Empty
+     *   Le  = Number of bytes to be read
+     */
+    static PCSC_CPP_CONSTEXPR_VECTOR CommandApdu readBinary(uint16_t pos, byte_type le)
+    {
+        return {0x00, 0xb0, byte_type(pos >> 8), byte_type(pos), le};
+    }
+
     byte_vector d;
 };
 
@@ -279,11 +301,8 @@ std::vector<Reader> listReaders();
 /** Transmit APDU command and verify that expected response is received. */
 void transmitApduWithExpectedResponse(const SmartCard& card, const CommandApdu& command);
 
-/** Read data length from currently selected file header, file must be ASN.1-encoded. */
-size_t readDataLengthFromAsn1(const SmartCard& card);
-
 /** Read lenght bytes from currently selected binary file in blockLength-sized chunks. */
-byte_vector readBinary(const SmartCard& card, const size_t length, byte_type blockLength);
+byte_vector readBinary(const SmartCard& card, const uint16_t length, byte_type blockLength = 0x00);
 
 // Errors.
 

lib/libpcsc-cpp/src/utils.cpp

@@ -23,34 +23,16 @@
 #include "pcsc-cpp/pcsc-cpp.hpp"
 #include "pcsc-cpp/pcsc-cpp-utils.hpp"
 
-#include <sstream>
+#include <algorithm>
 #include <iomanip>
+#include <sstream>
 
 using namespace pcsc_cpp;
 using namespace std::string_literals;
 
-#ifdef HIBYTE
-#undef HIBYTE
-#endif
-#ifdef LOBYTE
-#undef LOBYTE
-#endif
-
-constexpr byte_type HIBYTE(size_t w) noexcept
-{
-    return static_cast<byte_type>((w >> 8) & 0xff);
-}
-constexpr byte_type LOBYTE(size_t w) noexcept
-{
-    return static_cast<byte_type>(w & 0xff);
-}
-
 namespace
 {
 
-const byte_type DER_SEQUENCE_TYPE_TAG = 0x30;
-const byte_type DER_TWO_BYTE_LENGTH = 0x82;
-
 class UnexpectedResponseError : public Error
 {
 public:
@@ -93,68 +75,25 @@ void transmitApduWithExpectedResponse(const SmartCard& card, const CommandApdu&
     }
 }
 
-size_t readDataLengthFromAsn1(const SmartCard& card)
-{
-    // p1 - offset size first byte, 0
-    // p2 - offset size second byte, 0
-    // le - number of bytes to read, need 4 bytes from start for length
-    const CommandApdu readBinary4Bytes {0x00, 0xb0, 0x00, 0x00, 0x04};
-
-    auto response = card.transmit(readBinary4Bytes);
-
-    // Verify expected DER header, first byte must be SEQUENCE.
-    if (response.data[0] != DER_SEQUENCE_TYPE_TAG) {
-        // TODO: more specific exception
-        THROW(Error,
-              "readDataLengthFromAsn1(): First byte must be SEQUENCE (0x30), but is "s
-                  + int2hexstr(response.data[0]));
-    }
-
-    // TODO: support other lenghts besides 2.
-    // Assume 2-byte length, so second byte must be 0x82.
-    if (response.data[1] != DER_TWO_BYTE_LENGTH) {
-        // TODO: more specific exception
-        THROW(Error,
-              "readDataLengthFromAsn1(): Second byte must be two-byte length indicator "s
-              "(0x82), but is "s
-                  + int2hexstr(response.data[1]));
-    }
-
-    // Read 2-byte length field at offset 2 and 3 and add the 4 DER length bytes.
-    const auto length = size_t((response.data[2] << 8) + response.data[3] + 4);
-    if (length < 128 || length > 0x0f00) {
-        // TODO: more specific exception
-        THROW(Error,
-              "readDataLengthFromAsn1(): Unexpected data length in DER header: "s
-                  + std::to_string(length));
-    }
-
-    return length;
-}
-
-byte_vector readBinary(const SmartCard& card, const size_t length, byte_type blockLength)
+byte_vector readBinary(const SmartCard& card, const uint16_t length, byte_type blockLength)
 {
-    auto lengthCounter = length;
-    auto resultBytes = byte_vector {};
-
-    for (size_t offset = 0; lengthCounter != 0;
-         offset += blockLength, lengthCounter -= blockLength) {
-
-        if (blockLength > lengthCounter) {
-            blockLength = byte_type(lengthCounter);
+    byte_vector resultBytes;
+    resultBytes.reserve(length);
+    while (resultBytes.size() < length) {
+        byte_type chunk = byte_type(std::min<size_t>(length - resultBytes.size(), blockLength));
+        auto response = card.transmit(CommandApdu::readBinary(uint16_t(resultBytes.size()), chunk));
+        if (chunk > 0 && response.data.size() != chunk) {
+            THROW(Error,
+                  "readBinary(): Invalid length received: "s + std::to_string(response.data.size())
+                      + " excpected: " + std::to_string(chunk));
         }
-
-        CommandApdu readBinary {0x00, 0xb0, HIBYTE(offset), LOBYTE(offset), blockLength};
-        auto response = card.transmit(readBinary);
-
         resultBytes.insert(resultBytes.end(), response.data.cbegin(), response.data.cend());
     }
-
     if (resultBytes.size() != length) {
-        // TODO: more specific exception
-        THROW(Error, "readBinary(): Invalid length: "s + std::to_string(resultBytes.size()));
+        THROW(Error,
+              "readBinary(): Invalid length received: "s + std::to_string(resultBytes.size())
+                  + " excpected: " + std::to_string(length));
     }
-
     return resultBytes;
 }
 

src/electronic-ids/pcsc/EIDIDEMIA.cpp

@@ -46,8 +46,8 @@ const auto ADF1_AID = CommandApdu::select(
 const auto ADF2_AID = CommandApdu::select(0x04,
                                           {0x51, 0x53, 0x43, 0x44, 0x20, 0x41, 0x70, 0x70, 0x6C,
                                            0x69, 0x63, 0x61, 0x74, 0x69, 0x6F, 0x6E});
-const auto AUTH_CERT = CommandApdu::select(0x09, {0xAD, 0xF1, 0x34, 0x01});
-const auto SIGN_CERT = CommandApdu::select(0x09, {0xAD, 0xF2, 0x34, 0x1F});
+const auto AUTH_CERT = CommandApdu::selectEF(0x09, {0xAD, 0xF1, 0x34, 0x01});
+const auto SIGN_CERT = CommandApdu::selectEF(0x09, {0xAD, 0xF2, 0x34, 0x1F});
 
 } // namespace
 
@@ -69,7 +69,7 @@ void EIDIDEMIA::selectADF2() const
 byte_vector EIDIDEMIA::getCertificateImpl(const CertificateType type) const
 {
     selectMain();
-    return electronic_id::getCertificate(*card, type.isAuthentication() ? AUTH_CERT : SIGN_CERT);
+    return readFile(*card, type.isAuthentication() ? AUTH_CERT : SIGN_CERT, 0xC0);
 }
 
 EIDIDEMIA::KeyInfo EIDIDEMIA::authKeyRef() const

src/electronic-ids/pcsc/FinEID.cpp

@@ -43,9 +43,9 @@ namespace
 
 const auto SELECT_MAIN_AID = CommandApdu::select(
     0x04, {0xa0, 0x00, 0x00, 0x00, 0x63, 0x50, 0x4b, 0x43, 0x53, 0x2d, 0x31, 0x35});
-const auto SELECT_AUTH_CERT_FILE = CommandApdu::select(0x08, {0x43, 0x31});
-const auto SELECT_SIGN_CERT_FILE_V3 = CommandApdu::select(0x08, {0x50, 0x16, 0x43, 0x35});
-const auto SELECT_SIGN_CERT_FILE_V4 = CommandApdu::select(0x08, {0x50, 0x16, 0x43, 0x32});
+const auto SELECT_AUTH_CERT_FILE = CommandApdu::selectEF(0x08, {0x43, 0x31});
+const auto SELECT_SIGN_CERT_FILE_V3 = CommandApdu::selectEF(0x08, {0x50, 0x16, 0x43, 0x35});
+const auto SELECT_SIGN_CERT_FILE_V4 = CommandApdu::selectEF(0x08, {0x50, 0x16, 0x43, 0x32});
 
 constexpr byte_type PIN_PADDING_CHAR = 0x00;
 constexpr byte_type AUTH_PIN_REFERENCE = 0x11;
@@ -64,8 +64,8 @@ namespace electronic_id
 byte_vector FinEIDv3::getCertificateImpl(const CertificateType type) const
 {
     transmitApduWithExpectedResponse(*card, SELECT_MAIN_AID);
-    return electronic_id::getCertificate(
-        *card, type.isAuthentication() ? SELECT_AUTH_CERT_FILE : SELECT_SIGN_CERT_FILE_V3);
+    return readFile(*card,
+                    type.isAuthentication() ? SELECT_AUTH_CERT_FILE : SELECT_SIGN_CERT_FILE_V3);
 }
 
 byte_vector FinEIDv3::signWithAuthKeyImpl(byte_vector&& pin, const byte_vector& hash) const
@@ -179,8 +179,8 @@ ElectronicID::PinRetriesRemainingAndMax FinEIDv3::pinRetriesLeft(byte_type pinRe
 byte_vector FinEIDv4::getCertificateImpl(const CertificateType type) const
 {
     transmitApduWithExpectedResponse(*card, SELECT_MAIN_AID);
-    return electronic_id::getCertificate(
-        *card, type.isAuthentication() ? SELECT_AUTH_CERT_FILE : SELECT_SIGN_CERT_FILE_V4);
+    return readFile(*card,
+                    type.isAuthentication() ? SELECT_AUTH_CERT_FILE : SELECT_SIGN_CERT_FILE_V4);
 }
 
 byte_vector FinEIDv4::signWithAuthKeyImpl(byte_vector&& pin, const byte_vector& hash) const

src/electronic-ids/pcsc/LatEIDIDEMIAv2.cpp

@@ -63,7 +63,7 @@ byte_vector LatEIDIDEMIAV2::getCertificateImpl(const CertificateType type) const
     auto info =
         readDCODInfo(CERT_FILE_REF, type.isAuthentication() ? data->authCache : data->signCache);
     if (TLV id = TLV::path(info, 0x30, 0xA1, 0x30, 0x30, 0x04)) {
-        return electronic_id::getCertificate(*card, CommandApdu::select(0x02, {id.begin, id.end}));
+        return readFile(*card, CommandApdu::selectEF(0x02, {id.begin, id.end}), 0xC0);
     }
     THROW(SmartCardError, "EF.CD reference not found");
 }
@@ -114,24 +114,20 @@ const byte_vector& LatEIDIDEMIAV2::readEF_File(byte_vector file, C& cache) const
     if (auto it = cache.find(file); it != cache.end()) {
         return it->second;
     }
-    auto response = card->transmit({0x00, 0xA4, 0x02, 0x04, file, 0x00});
-    if (!response.isOK()) {
-        THROW(SmartCardError, "Failed to read EF file");
-    }
-    TLV size = TLV::path(response.data, 0x62, 0x80);
-    if (!size || size.length != 2) {
-        THROW(SmartCardError, "Failed to read EF file length");
-    }
-    return cache[std::move(file)] =
-               readBinary(*card, size_t(*size.begin << 8) + *(size.begin + 1), 0xFF);
+    return cache[std::move(file)] = readFile(*card, CommandApdu::selectEF(0x02, file));
 }
 
 template <class C>
 const byte_vector& LatEIDIDEMIAV2::readDCODInfo(byte_type type, C& cache) const
 {
     const auto info = readEF_File(EF_OD, cache);
-    if (auto file = TLV::path(info, type, 0x30, 0x04); file && file.length == 2) {
-        return readEF_File({file.begin, file.end}, cache);
+    for (TLV ref(info); ref; ++ref) {
+        if (ref.tag != type) {
+            continue;
+        }
+        if (auto file = ref[0x30][0x04]; file && file.length == 2) {
+            return readEF_File({file.begin, file.end}, cache);
+        }
     }
     THROW(SmartCardError, "EF.DCOD reference not found");
 }
@@ -144,7 +140,7 @@ EIDIDEMIA::KeyInfo LatEIDIDEMIAV2::readPrKDInfo(byte_type keyID, C& cache) const
         THROW(SmartCardError, "EF.PrKD reference not found");
     }
     TLV prKD(info);
-    TLV key = TLV::path(prKD.child(), 0x30);
+    TLV key = prKD[0x30];
     key = TLV::path(++key, 0x30, 0x02);
     return {key.length == 2 ? *std::next(key.begin) : keyID, prKD.tag == 0xA0};
 }