Implement setting of 'identity' for NitroKey Start.

openpgp-card/src/apdu/commands.rs

@@ -71,6 +71,11 @@ pub(crate) fn get_firmware_version() -> Command {
     Command::new(0x00, 0xF1, 0x00, 0x00, vec![])
 }
 
+/// Set identity [0-2] (NitroKey Start specific(?))
+pub(crate) fn set_identity(id: u8) -> Command {
+    Command::new(0x00, 0x85, 0x00, id, vec![])
+}
+
 /// GET RESPONSE
 pub(crate) fn get_response() -> Command {
     Command::new(0x00, 0xC0, 0x00, 0x00, vec![])

openpgp-card/src/card_app.rs

@@ -18,7 +18,9 @@ use crate::crypto_data::{
     CardUploadableKey, Cryptogram, Hash, PublicKeyMaterial,
 };
 use crate::tlv::{tag::Tag, value::Value, Tlv};
-use crate::{apdu, keys, CardCaps, CardClient, CardClientBox, KeyType};
+use crate::{
+    apdu, keys, CardCaps, CardClient, CardClientBox, KeyType, SmartcardError,
+};
 use crate::{Error, StatusBytes};
 
 /// Low-level access to OpenPGP card functionality.
@@ -244,6 +246,26 @@ impl CardApp {
         Ok(resp.data()?.into())
     }
 
+    /// Set identity (Nitrokey Start specific (?)).
+    /// [see:
+    /// https://docs.nitrokey.com/start/linux/multiple-identities.html
+    /// https://github.com/Nitrokey/nitrokey-start-firmware/pull/33/]
+    pub fn set_identity(&mut self, id: u8) -> Result<Vec<u8>> {
+        let resp = apdu::send_command(
+            self.card_client(),
+            commands::set_identity(id),
+            false,
+        );
+
+        // Apparently it's normal to get "NotTransacted" from pcsclite when
+        // the identity switch was successful.
+        if let Err(Error::Smartcard(SmartcardError::NotTransacted)) = resp {
+            Ok(vec![])
+        } else {
+            Ok(resp?.data()?.into())
+        }
+    }
+
     /// SELECT DATA "select a DO in the current template"
     /// (e.g. for cardholder certificate)
     pub fn select_data(

openpgp-card/src/errors.rs

@@ -179,6 +179,9 @@ pub enum SmartcardError {
     #[error("Failed to connect to the card: {0}")]
     SmartCardConnectionError(String),
 
+    #[error("NotTransacted (SCARD_E_NOT_TRANSACTED)")]
+    NotTransacted,
+
     #[error("Generic SmartCard Error: {0}")]
     Error(String),
 }

openpgp-card/src/lib.rs

@@ -51,7 +51,11 @@ pub trait CardClient {
     ///
     /// `buf_size` is a hint to the backend (the backend may ignore it)
     /// indicating the expected maximum response size.
-    fn transmit(&mut self, cmd: &[u8], buf_size: usize) -> Result<Vec<u8>>;
+    fn transmit(
+        &mut self,
+        cmd: &[u8],
+        buf_size: usize,
+    ) -> Result<Vec<u8>, Error>;
 
     /// Set the card capabilities in the CardClient.
     ///

pcsc/src/lib.rs

@@ -136,15 +136,25 @@ impl PcscClient {
 }
 
 impl CardClient for PcscClient {
-    fn transmit(&mut self, cmd: &[u8], buf_size: usize) -> Result<Vec<u8>> {
+    fn transmit(
+        &mut self,
+        cmd: &[u8],
+        buf_size: usize,
+    ) -> Result<Vec<u8>, Error> {
         let mut resp_buffer = vec![0; buf_size];
 
-        let resp = self.card.transmit(cmd, &mut resp_buffer).map_err(|e| {
-            Error::Smartcard(SmartcardError::Error(format!(
-                "Transmit failed: {:?}",
-                e
-            )))
-        })?;
+        let resp =
+            self.card.transmit(cmd, &mut resp_buffer).map_err(
+                |e| match e {
+                    pcsc::Error::NotTransacted => {
+                        Error::Smartcard(SmartcardError::NotTransacted)
+                    }
+                    _ => Error::Smartcard(SmartcardError::Error(format!(
+                        "Transmit failed: {:?}",
+                        e
+                    ))),
+                },
+            )?;
 
         log::debug!(" <- APDU response: {:x?}", resp);
 

scdc/src/lib.rs

@@ -194,7 +194,7 @@ impl ScdClient {
 }
 
 impl CardClient for ScdClient {
-    fn transmit(&mut self, cmd: &[u8], _: usize) -> Result<Vec<u8>> {
+    fn transmit(&mut self, cmd: &[u8], _: usize) -> Result<Vec<u8>, Error> {
         log::trace!("SCDC cmd len {}", cmd.len());
 
         let hex = hex::encode(cmd);
@@ -215,10 +215,10 @@ impl CardClient for ScdClient {
         log::debug!("SCDC command: '{}'", send);
 
         if send.len() > ASSUAN_LINELENGTH {
-            return Err(anyhow!(
+            return Err(Error::InternalError(anyhow!(
                 "APDU command is too long ({}) to send via Assuan",
                 send.len()
-            ));
+            )));
         }
 
         self.agent.send(send)?;
@@ -228,10 +228,10 @@ impl CardClient for ScdClient {
         while let Some(response) = rt.block_on(self.agent.next()) {
             log::debug!("res: {:x?}", response);
             if response.is_err() {
-                return Err(anyhow!(
+                return Err(Error::InternalError(anyhow!(
                     "Unexpected error response from SCD {:?}",
                     response
-                ));
+                )));
             }
 
             if let Ok(Response::Data { partial }) = response {
@@ -246,7 +246,7 @@ impl CardClient for ScdClient {
             }
         }
 
-        Err(anyhow!("no response found"))
+        Err(Error::InternalError(anyhow!("no response found")))
     }
 
     fn init_caps(&mut self, caps: CardCaps) {

tools/src/bin/opgpcard/cli.rs

@@ -31,6 +31,13 @@ pub enum Command {
         #[structopt(name = "card ident", short = "c", long = "card")]
         ident: String,
     },
+    SetIdentity {
+        #[structopt(name = "card ident", short = "c", long = "card")]
+        ident: String,
+
+        #[structopt(name = "identity")]
+        id: u8,
+    },
     Admin {
         #[structopt(name = "card ident", short = "c", long = "card")]
         ident: String,

tools/src/bin/opgpcard/main.rs

@@ -34,6 +34,9 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         cli::Command::Status { ident, verbose } => {
             print_status(ident, verbose)?;
         }
+        cli::Command::SetIdentity { ident, id } => {
+            set_identity(&ident, id)?;
+        }
         cli::Command::Decrypt {
             ident,
             user_pin,
@@ -147,6 +150,17 @@ fn list_cards() -> Result<()> {
     Ok(())
 }
 
+fn set_identity(
+    ident: &str,
+    id: u8,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let mut card = util::open_card(ident)?;
+
+    card.set_identity(id)?;
+
+    Ok(())
+}
+
 fn print_status(ident: Option<String>, verbose: bool) -> Result<()> {
     let mut ca = if let Some(ident) = ident {
         util::open_card(&ident)?