From c4457576335d6937defff56a8cc5f3cdd61d30ba Mon Sep 17 00:00:00 2001
From: Heiko Schaefer <heiko@schaefer.name>
Date: Wed, 14 Jul 2021 21:59:33 +0200
Subject: [PATCH] Implement get_key_generation_times()

---
 openpgp-card/src/card_app.rs                  | 19 +++++-
 openpgp-card/src/key_upload.rs                |  1 +
 .../src/parse/key_generation_times.rs         | 61 +++++++++++++++++++
 openpgp-card/src/parse/mod.rs                 |  1 +
 4 files changed, 79 insertions(+), 3 deletions(-)
 create mode 100644 openpgp-card/src/parse/key_generation_times.rs

diff --git a/openpgp-card/src/card_app.rs b/openpgp-card/src/card_app.rs
index ea7c05b..941bde5 100644
--- a/openpgp-card/src/card_app.rs
+++ b/openpgp-card/src/card_app.rs
@@ -16,11 +16,12 @@ use anyhow::{anyhow, Result};
 
 use crate::apdu::{commands, response::Response};
 use crate::errors::OpenpgpCardError;
+use crate::parse::key_generation_times::KeyGeneration;
 use crate::parse::{
     algo_attrs::Algo, algo_info::AlgoInfo, application_id::ApplicationId,
     cardholder::CardHolder, extended_cap::ExtendedCap,
     extended_length_info::ExtendedLengthInfo, fingerprint,
-    historical::Historical, pw_status::PWStatus, KeySet,
+    historical::Historical, key_generation_times, pw_status::PWStatus, KeySet,
 };
 use crate::tlv::{tag::Tag, Tlv, TlvEntry};
 use crate::{
@@ -236,8 +237,20 @@ impl CardApp {
         unimplemented!()
     }
 
-    pub fn get_key_generation_times() {
-        unimplemented!()
+    pub fn get_key_generation_times(
+        ard: &Tlv,
+    ) -> Result<KeySet<KeyGeneration>, OpenpgpCardError> {
+        let kg = ard.find(&Tag::from([0xCD]));
+
+        if let Some(kg) = kg {
+            let kg = key_generation_times::from(&kg.serialize())?;
+
+            log::debug!("Key generation: {:x?}", kg);
+
+            Ok(kg)
+        } else {
+            Err(anyhow!("Failed to get key generation times.").into())
+        }
     }
 
     pub fn get_key_information() {
diff --git a/openpgp-card/src/key_upload.rs b/openpgp-card/src/key_upload.rs
index 27aea12..c24099c 100644
--- a/openpgp-card/src/key_upload.rs
+++ b/openpgp-card/src/key_upload.rs
@@ -387,6 +387,7 @@ fn copy_key_to_card(
         .copied()
         .collect();
 
+    // Generation date/time
     let time_cmd =
         commands::put_data(&[key_type.get_timestamp_put_tag()], time_value);
 
diff --git a/openpgp-card/src/parse/key_generation_times.rs b/openpgp-card/src/parse/key_generation_times.rs
new file mode 100644
index 0000000..b1ce671
--- /dev/null
+++ b/openpgp-card/src/parse/key_generation_times.rs
@@ -0,0 +1,61 @@
+// SPDX-FileCopyrightText: 2021 Heiko Schaefer <heiko@schaefer.name>
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use anyhow::anyhow;
+use nom::{
+    bytes::complete as bytes, combinator, number::complete as number, sequence,
+};
+use std::fmt;
+
+use crate::errors::OpenpgpCardError;
+use crate::parse::KeySet;
+
+#[derive(Clone, Eq, PartialEq, Debug)]
+pub struct KeyGeneration(u32);
+
+impl From<u32> for KeyGeneration {
+    fn from(data: u32) -> Self {
+        Self(data)
+    }
+}
+
+fn gen_time(input: &[u8]) -> nom::IResult<&[u8], u32> {
+    (number::be_u32)(input)
+}
+
+fn key_generation(input: &[u8]) -> nom::IResult<&[u8], Option<KeyGeneration>> {
+    combinator::map(gen_time, |kg| match kg {
+        0 => None,
+        kg => Some(KeyGeneration(kg)),
+    })(input)
+}
+
+fn key_generation_set(
+    input: &[u8],
+) -> nom::IResult<&[u8], KeySet<KeyGeneration>> {
+    combinator::into(sequence::tuple((
+        key_generation,
+        key_generation,
+        key_generation,
+    )))(input)
+}
+
+pub fn from(input: &[u8]) -> Result<KeySet<KeyGeneration>, OpenpgpCardError> {
+    // List of generation dates/times of key pairs, binary.
+    // 4 bytes, Big Endian each for Sig, Dec and Aut. Each
+    // value shall be seconds since Jan 1, 1970. Default
+    // value is 00000000 (not specified).
+
+    log::trace!(
+        "Key generation times from input: {:x?}, len {}",
+        input,
+        input.len()
+    );
+
+    // The input may be longer than 3 key generation times, don't fail if it
+    // hasn't been completely consumed.
+    self::key_generation_set(input)
+        .map(|res| res.1)
+        .map_err(|err| anyhow!("Parsing failed: {:?}", err))
+        .map_err(OpenpgpCardError::InternalError)
+}
diff --git a/openpgp-card/src/parse/mod.rs b/openpgp-card/src/parse/mod.rs
index 2da0124..1b01b13 100644
--- a/openpgp-card/src/parse/mod.rs
+++ b/openpgp-card/src/parse/mod.rs
@@ -12,6 +12,7 @@ pub mod extended_cap;
 pub mod extended_length_info;
 pub mod fingerprint;
 pub mod historical;
+pub mod key_generation_times;
 pub mod pw_status;
 
 use anyhow::{anyhow, Error};