aboutsummaryrefslogtreecommitdiff
path: root/src/pinentry.rs
diff options
context:
space:
mode:
Diffstat (limited to 'src/pinentry.rs')
-rw-r--r--src/pinentry.rs404
1 files changed, 404 insertions, 0 deletions
diff --git a/src/pinentry.rs b/src/pinentry.rs
new file mode 100644
index 0000000..fd47657
--- /dev/null
+++ b/src/pinentry.rs
@@ -0,0 +1,404 @@
+// pinentry.rs
+
+// *************************************************************************
+// * Copyright (C) 2017-2020 Daniel Mueller (deso@posteo.net) *
+// * *
+// * This program is free software: you can redistribute it and/or modify *
+// * it under the terms of the GNU General Public License as published by *
+// * the Free Software Foundation, either version 3 of the License, or *
+// * (at your option) any later version. *
+// * *
+// * This program is distributed in the hope that it will be useful, *
+// * but WITHOUT ANY WARRANTY; without even the implied warranty of *
+// * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
+// * GNU General Public License for more details. *
+// * *
+// * You should have received a copy of the GNU General Public License *
+// * along with this program. If not, see <http://www.gnu.org/licenses/>. *
+// *************************************************************************
+
+use std::borrow;
+use std::fmt;
+use std::io;
+use std::process;
+use std::str;
+
+use crate::args;
+use crate::error::Error;
+
+type CowStr = borrow::Cow<'static, str>;
+
+/// PIN type requested from pinentry.
+///
+/// The available PIN types correspond to the PIN types used by the Nitrokey devices: user and
+/// admin.
+#[allow(unused_doc_comments)]
+Enum! {PinType, [
+ Admin => "admin",
+ User => "user",
+]}
+
+/// A trait representing a secret to be entered by the user.
+pub trait SecretEntry: fmt::Debug {
+ /// The cache ID to use for this secret.
+ fn cache_id(&self) -> Option<CowStr>;
+ /// The prompt to display when asking for the secret.
+ fn prompt(&self) -> CowStr;
+ /// The description to display when asking for the secret.
+ fn description(&self, mode: Mode) -> CowStr;
+ /// The minimum number of characters the secret needs to have.
+ fn min_len(&self) -> u8;
+}
+
+#[derive(Debug)]
+pub struct PinEntry {
+ pin_type: PinType,
+ model: nitrokey::Model,
+ serial: String,
+}
+
+impl PinEntry {
+ pub fn from<'mgr, D>(pin_type: PinType, device: &D) -> crate::Result<Self>
+ where
+ D: nitrokey::Device<'mgr>,
+ {
+ let model = device.get_model();
+ let serial = device.get_serial_number()?;
+ Ok(Self {
+ pin_type,
+ model,
+ serial,
+ })
+ }
+
+ pub fn pin_type(&self) -> PinType {
+ self.pin_type
+ }
+}
+
+impl SecretEntry for PinEntry {
+ fn cache_id(&self) -> Option<CowStr> {
+ let model = self.model.to_string().to_lowercase();
+ let suffix = format!("{}:{}", model, self.serial);
+ let cache_id = match self.pin_type {
+ PinType::Admin => format!("nitrocli:admin:{}", suffix),
+ PinType::User => format!("nitrocli:user:{}", suffix),
+ };
+ Some(cache_id.into())
+ }
+
+ fn prompt(&self) -> CowStr {
+ match self.pin_type {
+ PinType::Admin => "Admin PIN",
+ PinType::User => "User PIN",
+ }
+ .into()
+ }
+
+ fn description(&self, mode: Mode) -> CowStr {
+ format!(
+ "{} for\rNitrokey {} {}",
+ match self.pin_type {
+ PinType::Admin => match mode {
+ Mode::Choose => "Please enter a new admin PIN",
+ Mode::Confirm => "Please confirm the new admin PIN",
+ Mode::Query => "Please enter the admin PIN",
+ },
+ PinType::User => match mode {
+ Mode::Choose => "Please enter a new user PIN",
+ Mode::Confirm => "Please confirm the new user PIN",
+ Mode::Query => "Please enter the user PIN",
+ },
+ },
+ self.model,
+ self.serial,
+ )
+ .into()
+ }
+
+ fn min_len(&self) -> u8 {
+ match self.pin_type {
+ PinType::Admin => 8,
+ PinType::User => 6,
+ }
+ }
+}
+
+#[derive(Debug)]
+pub struct PwdEntry {
+ model: nitrokey::Model,
+ serial: String,
+}
+
+impl PwdEntry {
+ pub fn from<'mgr, D>(device: &D) -> crate::Result<Self>
+ where
+ D: nitrokey::Device<'mgr>,
+ {
+ let model = device.get_model();
+ let serial = device.get_serial_number()?;
+ Ok(Self { model, serial })
+ }
+}
+
+impl SecretEntry for PwdEntry {
+ fn cache_id(&self) -> Option<CowStr> {
+ None
+ }
+
+ fn prompt(&self) -> CowStr {
+ "Password".into()
+ }
+
+ fn description(&self, mode: Mode) -> CowStr {
+ format!(
+ "{} for\rNitrokey {} {}",
+ match mode {
+ Mode::Choose => "Please enter a new hidden volume password",
+ Mode::Confirm => "Please confirm the new hidden volume password",
+ Mode::Query => "Please enter a hidden volume password",
+ },
+ self.model,
+ self.serial,
+ )
+ .into()
+ }
+
+ fn min_len(&self) -> u8 {
+ // More or less arbitrary minimum length based on the fact that the
+ // manual mentions six letter passwords in examples. Users
+ // *probably* should go longer than that, but we don't want to be
+ // too opinionated.
+ 6
+ }
+}
+
+/// Secret entry mode for pinentry.
+///
+/// This enum describes the context of the pinentry query, for example
+/// prompting for the current secret or requesting a new one. The mode
+/// may affect the pinentry description and whether a quality bar is
+/// shown.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum Mode {
+ /// Let the user choose a new secret.
+ Choose,
+ /// Let the user confirm the previously chosen secret.
+ Confirm,
+ /// Query an existing secret.
+ Query,
+}
+
+impl Mode {
+ fn show_quality_bar(self) -> bool {
+ self == Mode::Choose
+ }
+}
+
+fn parse_pinentry_pin<R>(response: R) -> crate::Result<String>
+where
+ R: AsRef<str>,
+{
+ let string = response.as_ref();
+ let lines: Vec<&str> = string.lines().collect();
+
+ // We expect the response to be of the form:
+ // > D passphrase
+ // > OK
+ // or potentially:
+ // > ERR 83886179 Operation cancelled <Pinentry>
+ if lines.len() == 2 && lines[1] == "OK" && lines[0].starts_with("D ") {
+ // We got the only valid answer we accept.
+ let (_, pass) = lines[0].split_at(2);
+ return Ok(pass.to_string());
+ }
+
+ // Check if we are dealing with a special "ERR " line and report that
+ // specially.
+ if !lines.is_empty() && lines[0].starts_with("ERR ") {
+ let (_, error) = lines[0].split_at(4);
+ return Err(Error::from(error));
+ }
+ Err(Error::Error(format!("Unexpected response: {}", string)))
+}
+
+/// Inquire a secret from the user.
+///
+/// This function inquires a secret from the user or returns a cached
+/// entry, if available (and if caching is not disabled for the given
+/// execution context). If an error message is set, it is displayed in
+/// the entry dialog. The mode describes the context of the pinentry
+/// dialog. It is used to choose an appropriate description and to
+/// decide whether a quality bar is shown in the dialog.
+pub fn inquire<E>(
+ ctx: &mut args::ExecCtx<'_>,
+ entry: &E,
+ mode: Mode,
+ error_msg: Option<&str>,
+) -> crate::Result<String>
+where
+ E: SecretEntry,
+{
+ let cache_id = entry
+ .cache_id()
+ .and_then(|id| if ctx.no_cache { None } else { Some(id) })
+ // "X" is a sentinel value indicating that no caching is desired.
+ .unwrap_or_else(|| "X".into())
+ .into();
+
+ let error_msg = error_msg
+ .map(|msg| msg.replace(" ", "+"))
+ .unwrap_or_else(|| String::from("+"));
+ let prompt = entry.prompt().replace(" ", "+");
+ let description = entry.description(mode).replace(" ", "+");
+
+ let args = vec![cache_id, error_msg, prompt, description].join(" ");
+ let mut command = "GET_PASSPHRASE --data ".to_string();
+ if mode.show_quality_bar() {
+ command += "--qualitybar ";
+ }
+ command += &args;
+ // An error reported for the GET_PASSPHRASE command does not actually
+ // cause gpg-connect-agent to exit with a non-zero error code, we have
+ // to evaluate the output to determine success/failure.
+ let output = process::Command::new("gpg-connect-agent")
+ .arg(command)
+ .arg("/bye")
+ .output()
+ .map_err(|err| match err.kind() {
+ io::ErrorKind::NotFound => {
+ io::Error::new(io::ErrorKind::NotFound, "gpg-connect-agent not found")
+ }
+ _ => err,
+ })?;
+ parse_pinentry_pin(str::from_utf8(&output.stdout)?)
+}
+
+fn check<E>(entry: &E, secret: &str) -> crate::Result<()>
+where
+ E: SecretEntry,
+{
+ if secret.len() < usize::from(entry.min_len()) {
+ Err(Error::Error(format!(
+ "The secret must be at least {} characters long",
+ entry.min_len()
+ )))
+ } else {
+ Ok(())
+ }
+}
+
+pub fn choose<E>(ctx: &mut args::ExecCtx<'_>, entry: &E) -> crate::Result<String>
+where
+ E: SecretEntry,
+{
+ clear(entry)?;
+ let chosen = inquire(ctx, entry, Mode::Choose, None)?;
+ clear(entry)?;
+ check(entry, &chosen)?;
+
+ let confirmed = inquire(ctx, entry, Mode::Confirm, None)?;
+ clear(entry)?;
+
+ if chosen != confirmed {
+ Err(Error::from("Entered secrets do not match"))
+ } else {
+ Ok(chosen)
+ }
+}
+
+fn parse_pinentry_response<R>(response: R) -> crate::Result<()>
+where
+ R: AsRef<str>,
+{
+ let string = response.as_ref();
+ let lines = string.lines().collect::<Vec<_>>();
+
+ if lines.len() == 1 && lines[0] == "OK" {
+ // We got the only valid answer we accept.
+ return Ok(());
+ }
+ Err(Error::Error(format!("Unexpected response: {}", string)))
+}
+
+/// Clear the cached secret represented by the given entry.
+pub fn clear<E>(entry: &E) -> crate::Result<()>
+where
+ E: SecretEntry,
+{
+ if let Some(cache_id) = entry.cache_id() {
+ let command = format!("CLEAR_PASSPHRASE {}", cache_id);
+ let output = process::Command::new("gpg-connect-agent")
+ .arg(command)
+ .arg("/bye")
+ .output()?;
+
+ parse_pinentry_response(str::from_utf8(&output.stdout)?)
+ } else {
+ Ok(())
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn parse_pinentry_pin_good() {
+ let response = "D passphrase\nOK\n";
+ let expected = "passphrase";
+
+ assert_eq!(parse_pinentry_pin(response).unwrap(), expected)
+ }
+
+ #[test]
+ fn parse_pinentry_pin_error() {
+ let error = "83886179 Operation cancelled";
+ let response = "ERR ".to_string() + error + "\n";
+ let expected = error;
+
+ let error = parse_pinentry_pin(response);
+
+ if let Error::Error(ref e) = error.err().unwrap() {
+ assert_eq!(e, &expected);
+ } else {
+ panic!("Unexpected result");
+ }
+ }
+
+ #[test]
+ fn parse_pinentry_pin_unexpected() {
+ let response = "foobar\n";
+ let expected = format!("Unexpected response: {}", response);
+ let error = parse_pinentry_pin(response);
+
+ if let Error::Error(ref e) = error.err().unwrap() {
+ assert_eq!(e, &expected);
+ } else {
+ panic!("Unexpected result");
+ }
+ }
+
+ #[test]
+ fn parse_pinentry_response_ok() {
+ assert!(parse_pinentry_response("OK\n").is_ok())
+ }
+
+ #[test]
+ fn parse_pinentry_response_ok_no_newline() {
+ assert!(parse_pinentry_response("OK").is_ok())
+ }
+
+ #[test]
+ fn parse_pinentry_response_unexpected() {
+ let response = "ERR 42";
+ let expected = format!("Unexpected response: {}", response);
+ let error = parse_pinentry_response(response);
+
+ if let Error::Error(ref e) = error.err().unwrap() {
+ assert_eq!(e, &expected);
+ } else {
+ panic!("Unexpected result");
+ }
+ }
+}