OPEN-99: read cvc (#39)

read cv certificate

---------

Co-authored-by: Tobias Schwerdtfeger <this@tobias-schwerdtfeger.dev>
Co-authored-by: sandra.bieseke <sandra.bieseke@gematik.de>

Author: 3 people

core-modules/healthcard/Cargo.toml

@@ -45,11 +45,7 @@ once_cell = "1.21.3"
 num-bigint = "0.4"
 zeroize = { version = "1.8.1", features = ["zeroize_derive"] }
 uniffi = { version = "0.30.0", optional = true }
-clap = { version = "4.5.52", features = ["derive"], optional = true }
-pcsc = { version = "2.9.0", optional = true }
-serde = { version = "1.0.228", features = ["derive"], optional = true }
-serde_json = { version = "1.0.145", optional = true }
-
-[dev-dependencies]
-serde = { version = "1.0.228", features = ["derive"] }
-serde_json = "1.0.145"
+clap = { version = "4.5.40", optional = true, features = ["derive"] }
+serde = { version = "1.0.219", optional = true, features = ["derive"] }
+serde_json = { version = "1.0.117", optional = true }
+pcsc = { version = "2.8.2", optional = true }

core-modules/healthcard/src/bin/apdu_record.rs

@@ -29,6 +29,7 @@ fn main() {
     use clap::Parser;
     use crypto::ec::ec_key::{EcCurve, EcKeyPairSpec};
     use healthcard::exchange::apdu_tools::{PcscChannel, RecordingChannel};
+    use healthcard::exchange::certificate::{retrieve_certificate_from, CertificateFile};
     use healthcard::exchange::secure_channel::{establish_secure_channel_with, CardAccessNumber};
 
     if let Err(err) = run() {
@@ -58,6 +59,9 @@ fn main() {
         /// List available PC/SC readers and exit
         #[arg(long)]
         list_readers: bool,
+        /// Read certificates and print them as hex to stdout
+        #[arg(long)]
+        read_certificates: bool,
     }
 
     fn run() -> Result<(), String> {
@@ -80,13 +84,25 @@ fn main() {
         recorder.set_can(can.clone());
 
         let mut generated_keys = Vec::new();
-        establish_secure_channel_with(&mut recorder, &card_access_number, |curve: EcCurve| {
+        let mut secure_channel = establish_secure_channel_with(&mut recorder, &card_access_number, |curve: EcCurve| {
             let (public_key, private_key) = EcKeyPairSpec { curve: curve.clone() }.generate_keypair()?;
             generated_keys.push(hex::encode_upper(private_key.as_bytes()));
             Ok((public_key, private_key))
         })
         .map_err(|err| format!("PACE failed: {err}"))?;
 
+        if args.read_certificates {
+            let cert = retrieve_certificate_from(&mut secure_channel, CertificateFile::ChAutE256)
+                .map_err(|err| format!("read DF.ESIGN/EF.C.CH.AUT.E256 failed: {err}"))?;
+            print_certificate("DF.ESIGN/EF.C.CH.AUT.E256", &cert);
+
+            let cert = retrieve_certificate_from(&mut secure_channel, CertificateFile::EgkAutCvcE256)
+                .map_err(|err| format!("read MF/EF.C.eGK.AUT_CVC.E256 failed: {err}"))?;
+            print_certificate("MF/EF.C.eGK.AUT_CVC.E256", &cert);
+        }
+
+        drop(secure_channel);
+
         if !generated_keys.is_empty() {
             recorder.set_keys(generated_keys);
         }
@@ -96,6 +112,13 @@ fn main() {
         Ok(())
     }
 
+    fn print_certificate(label: &str, data: &[u8]) {
+        println!("{label} ({} bytes):", data.len());
+        for chunk in data.chunks(32) {
+            println!("  {}", hex::encode_upper(chunk));
+        }
+    }
+
     fn list_pcsc_readers() -> Result<(), String> {
         let ctx = pcsc::Context::establish(pcsc::Scope::User)
             .map_err(|err| format!("pcsc context establish failed: {err}"))?;

core-modules/healthcard/src/exchange/apdu_tools.rs

@@ -124,8 +124,8 @@ impl Transcript {
     pub fn fixed_key_generator(&self) -> Result<Option<EcKeyPairGenerator>, TranscriptError> {
         match &self.header.keys {
             Some(keys) => {
-                let decoded = keys.iter().map(hex::decode).collect::<Result<Vec<_>, _>>()?;
-                Ok(Some(FixedKeyGenerator::new(decoded).generator()))
+                let decoded = keys.iter().map(hex::decode).collect::<Result<Vec<_>, hex::FromHexError>>()?;
+                Ok(Some(Box::new(FixedKeyGenerator::new(decoded).generator())))
             }
             None => Ok(None),
         }
@@ -371,8 +371,8 @@ impl FixedKeyGenerator {
         Self { keys }
     }
 
-    pub fn generator(mut self) -> EcKeyPairGenerator {
-        Box::new(move |curve| {
+    pub fn generator(mut self) -> impl FnMut(EcCurve) -> Result<(EcPublicKey, EcPrivateKey), CryptoError> {
+        move |curve| {
             if self.keys.is_empty() {
                 return Err(CryptoError::InvalidKeyMaterial { context: "fixed key generator ran out of keys" });
             }
@@ -381,7 +381,7 @@ impl FixedKeyGenerator {
             let (public_key, private_key) = derive_keypair_from_scalar(curve.clone(), bytes)?;
             eprintln!("FixedKeyGenerator used key for {curve:?}: {key_hex}");
             Ok((public_key, private_key))
-        })
+        }
     }
 }
 

core-modules/healthcard/src/exchange/certificate.rs

@@ -29,6 +29,43 @@ use super::channel::CardChannelExt;
 use super::error::ExchangeError;
 use super::ids;
 
+/// Defines which certificate file to read from the card.
+#[derive(Clone, Copy, Debug)]
+pub enum CertificateFile {
+    /// X.509 certificate stored in `DF.ESIGN/EF.C.CH.AUT.E256`.
+    ChAutE256,
+    /// CV certificate stored in `MF/EF.C.eGK.AUT_CVC.E256`.
+    EgkAutCvcE256,
+}
+
+fn select_certificate_file<S>(session: &mut S, certificate: CertificateFile) -> Result<(), ExchangeError>
+where
+    S: CardChannelExt,
+{
+    match certificate {
+        CertificateFile::ChAutE256 => {
+            session.execute_command_success(&HealthCardCommand::select_aid(&ids::df_esign_aid()))?;
+            session.execute_command_success(&HealthCardCommand::select_fid_with_options(
+                &ids::ef_cch_aut_e256_fid(),
+                false,
+                true,
+                EXPECTED_LENGTH_WILDCARD_EXTENDED as i32,
+            ))?;
+        }
+        CertificateFile::EgkAutCvcE256 => {
+            session.execute_command_success(&HealthCardCommand::select(false, false))?;
+            session.execute_command_success(&HealthCardCommand::select_fid_with_options(
+                &ids::ef_c_egk_aut_cvc_e256_fid(),
+                false,
+                true,
+                EXPECTED_LENGTH_WILDCARD_EXTENDED as i32,
+            ))?;
+        }
+    }
+
+    Ok(())
+}
+
 /// Retrieve the X.509 certificate stored in `DF.ESIGN/EF.C.CH.AUT.E256`.
 ///
 /// The certificate is read in chunks using the READ BINARY command until the
@@ -37,13 +74,18 @@ pub fn retrieve_certificate<S>(session: &mut S) -> Result<Vec<u8>, ExchangeError
 where
     S: CardChannelExt,
 {
-    session.execute_command_success(&HealthCardCommand::select_aid(&ids::df_esign_aid()))?;
-    session.execute_command_success(&HealthCardCommand::select_fid_with_options(
-        &ids::ef_cch_aut_e256_fid(),
-        false,
-        true,
-        EXPECTED_LENGTH_WILDCARD_EXTENDED as i32,
-    ))?;
+    retrieve_certificate_from(session, CertificateFile::ChAutE256)
+}
+
+/// Retrieve a certificate file from the card.
+///
+/// The certificate is read in chunks using the READ BINARY command until the
+/// card indicates the end of the file.
+pub fn retrieve_certificate_from<S>(session: &mut S, certificate: CertificateFile) -> Result<Vec<u8>, ExchangeError>
+where
+    S: CardChannelExt,
+{
+    select_certificate_file(session, certificate)?;
 
     let mut certificate = Vec::new();
     let mut offset: i32 = 0;
@@ -71,6 +113,7 @@ where
 mod tests {
     use super::*;
     use crate::command::health_card_status::HealthCardResponseStatus;
+    use crate::command::select_command::SelectCommand;
     use crate::exchange::test_utils::MockSession;
 
     #[test]
@@ -95,4 +138,31 @@ mod tests {
             other => panic!("unexpected error {other:?}"),
         }
     }
+
+    #[test]
+    fn cv_certificate_selects_master_file() {
+        let mut session = MockSession::with_extended_support(
+            vec![vec![0x90, 0x00], vec![0x90, 0x00], vec![0xDE, 0xAD, 0x90, 0x00], vec![0xBE, 0xEF, 0x62, 0x82]],
+            true,
+        );
+
+        let cert = retrieve_certificate_from(&mut session, CertificateFile::EgkAutCvcE256).unwrap();
+        assert_eq!(cert, vec![0xDE, 0xAD, 0xBE, 0xEF]);
+        assert_eq!(
+            session.recorded[0],
+            HealthCardCommand::select(false, false).command_apdu(false).unwrap().to_bytes()
+        );
+        assert_eq!(
+            session.recorded[1],
+            HealthCardCommand::select_fid_with_options(
+                &ids::ef_c_egk_aut_cvc_e256_fid(),
+                false,
+                true,
+                EXPECTED_LENGTH_WILDCARD_EXTENDED as i32,
+            )
+            .command_apdu(false)
+            .unwrap()
+            .to_bytes()
+        );
+    }
 }

core-modules/healthcard/src/exchange/ids.rs

@@ -102,6 +102,16 @@ pub fn ef_cch_aut_e256_sfid() -> ShortFileIdentifier {
     short_file_identifier(0x04)
 }
 
+/// File identifier for `MF/EF.C.eGK.AUT_CVC.E256` (gemSpec_ObjSys Section 5.3.4).
+pub fn ef_c_egk_aut_cvc_e256_fid() -> FileIdentifier {
+    file_identifier(0x2F06)
+}
+
+/// Short file identifier for `MF/EF.C.eGK.AUT_CVC.E256` (gemSpec_ObjSys Section 5.3.4).
+pub fn ef_c_egk_aut_cvc_e256_sfid() -> ShortFileIdentifier {
+    short_file_identifier(0x06)
+}
+
 /// Key identifier for the `PrK.CH.AUT.E256` private key in `DF.ESIGN`.
 pub fn prk_ch_aut_e256() -> CardKey {
     CardKey::new(0x04).expect("constant key id must be valid")
@@ -135,6 +145,8 @@ mod tests {
         assert_eq!(ef_status_vd_sfid().value(), 0x0C);
         assert_eq!(ef_cch_aut_e256_fid().to_bytes(), [0xC5, 0x04]);
         assert_eq!(ef_cch_aut_e256_sfid().value(), 0x04);
+        assert_eq!(ef_c_egk_aut_cvc_e256_fid().to_bytes(), [0x2F, 0x06]);
+        assert_eq!(ef_c_egk_aut_cvc_e256_sfid().value(), 0x06);
 
         assert_eq!(prk_ch_aut_e256().key_id(), 0x04);
         assert_eq!(mr_pin_home_reference().pwd_id(), 0x02);

docs/tooling/apdu-tools.md

@@ -69,6 +69,16 @@ cargo run -p healthcard --bin apdu_record --features apdu-tools,pcsc -- \
   --out ./transcript.jsonl
 ```
 
+To additionally read the certificates and print them to the console:
+
+```sh
+cargo run -p healthcard --bin apdu_record --features apdu-tools,pcsc -- \
+  --reader "<PCSC reader name>" \
+  --can 123123 \
+  --out ./transcript.jsonl \
+  --read-certificates
+```
+
 APDU length options:
 
 - Default: uses extended-length APDUs when needed.