From d1f854f2f0de3b36af369c40572116a0731d849c Mon Sep 17 00:00:00 2001
From: Heiko Schaefer <heiko@schaefer.name>
Date: Sat, 3 Jul 2021 21:23:17 +0200
Subject: [PATCH] Implement get_pw_status_bytes()

---
 openpgp-card-sequoia/src/main.rs    |  3 ++
 openpgp-card/src/lib.rs             | 18 ++++++++--
 openpgp-card/src/parse/mod.rs       |  1 +
 openpgp-card/src/parse/pw_status.rs | 51 +++++++++++++++++++++++++++++
 4 files changed, 70 insertions(+), 3 deletions(-)
 create mode 100644 openpgp-card/src/parse/pw_status.rs

diff --git a/openpgp-card-sequoia/src/main.rs b/openpgp-card-sequoia/src/main.rs
index db91bc0..b6a5c94 100644
--- a/openpgp-card-sequoia/src/main.rs
+++ b/openpgp-card-sequoia/src/main.rs
@@ -48,6 +48,9 @@ fn main() -> Result<(), Box<dyn Error>> {
         let ext = oc.get_extended_capabilities()?;
         println!("extended_capabilities {:#x?}", ext);
 
+        let pws = oc.get_pw_status_bytes()?;
+        println!("PW Status Bytes {:#x?}", pws);
+
         // cardholder
 
         let ch = oc.get_cardholder_related_data()?;
diff --git a/openpgp-card/src/lib.rs b/openpgp-card/src/lib.rs
index 175c4fe..3925420 100644
--- a/openpgp-card/src/lib.rs
+++ b/openpgp-card/src/lib.rs
@@ -11,7 +11,7 @@ use parse::{
     algo_attrs::Algo, algo_info::AlgoInfo, application_id::ApplicationId,
     cardholder::CardHolder, extended_cap::ExtendedCap, extended_cap::Features,
     extended_length_info::ExtendedLengthInfo, fingerprint,
-    historical::Historical, KeySet,
+    historical::Historical, pw_status::PWStatus, KeySet,
 };
 use tlv::Tlv;
 
@@ -384,8 +384,20 @@ impl CardBase {
         }
     }
 
-    pub fn get_pw_status_bytes() {
-        unimplemented!()
+    /// PW status Bytes
+    pub fn get_pw_status_bytes(&self) -> Result<PWStatus> {
+        // get from cached "application related data"
+        let psb = self.ard.find(&Tag::from([0xc4]));
+
+        if let Some(psb) = psb {
+            let pws = PWStatus::try_from(&psb.serialize())?;
+
+            log::debug!("PW Status: {:x?}", pws);
+
+            Ok(pws)
+        } else {
+            Err(anyhow!("Failed to get PW status Bytes.").into())
+        }
     }
 
     pub fn get_fingerprints(
diff --git a/openpgp-card/src/parse/mod.rs b/openpgp-card/src/parse/mod.rs
index 6f5f66c..2da0124 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 pw_status;
 
 use anyhow::{anyhow, Error};
 
diff --git a/openpgp-card/src/parse/pw_status.rs b/openpgp-card/src/parse/pw_status.rs
new file mode 100644
index 0000000..8260fc5
--- /dev/null
+++ b/openpgp-card/src/parse/pw_status.rs
@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: 2021 Heiko Schaefer <heiko@schaefer.name>
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use crate::errors::OpenpgpCardError;
+use anyhow::anyhow;
+
+#[derive(Debug)]
+pub struct PWStatus {
+    pub(crate) pw1_cds_multi: bool,
+    pub(crate) pw1_derived: bool,
+    pub(crate) pw1_len: u8,
+    pub(crate) rc_len: u8,
+    pub(crate) pw3_derived: bool,
+    pub(crate) pw3_len: u8,
+    pub(crate) err_count_pw1: u8,
+    pub(crate) err_count_rst: u8,
+    pub(crate) err_count_pw3: u8,
+}
+
+impl PWStatus {
+    pub fn try_from(input: &[u8]) -> Result<Self, OpenpgpCardError> {
+        if input.len() == 7 {
+            let pw1_cds_multi = input[0] == 0x01;
+            let pw1_derived = input[1] & 0x80 != 0;
+            let pw1_len = input[1] & 0x7f;
+            let rc_len = input[2];
+            let pw3_derived = input[3] & 0x80 != 0;
+            let pw3_len = input[3] & 0x7f;
+            let err_count_pw1 = input[4];
+            let err_count_rst = input[5];
+            let err_count_pw3 = input[6];
+
+            Ok(Self {
+                pw1_cds_multi,
+                pw1_derived,
+                pw1_len,
+                rc_len,
+                pw3_derived,
+                pw3_len,
+                err_count_pw1,
+                err_count_rst,
+                err_count_pw3,
+            })
+        } else {
+            Err(OpenpgpCardError::InternalError(anyhow!(
+                "Unexpected length of PW Status Bytes: {}",
+                input.len()
+            )))
+        }
+    }
+}