openpgp-card: internal API tweaks

Reduce unnecessary use of ApplicationRelatedData.

openpgp-card/src/algorithm.rs

@@ -1,10 +1,10 @@
-// SPDX-FileCopyrightText: 2021 Heiko Schaefer <heiko@schaefer.name>
+// SPDX-FileCopyrightText: 2021-2023 Heiko Schaefer <heiko@schaefer.name>
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
-//! Data structures that define OpenPGP algorithms.
+//! Data structures that specify algorithms to use on an OpenPGP card.
 //!
-//! [`AlgorithmAttributes`] and its components model "Algorithm Attributes" as described in
-//! the OpenPGP card specification.
+//! [`AlgorithmAttributes`] (and its components) model "Algorithm Attributes"
+//! as described in the OpenPGP card specification.
 //!
 //! [`AlgoSimple`] offers a shorthand for specifying an algorithm,
 //! specifically for key generation on the card.
@@ -31,7 +31,7 @@ pub enum AlgoSimple {
 }
 
 impl TryFrom<&str> for AlgoSimple {
-    type Error = crate::Error;
+    type Error = Error;
 
     fn try_from(algo: &str) -> Result<Self, Self::Error> {
         use AlgoSimple::*;
@@ -80,25 +80,37 @@ impl AlgoSimple {
     /// This mapping differs between cards, based on `ard` and `algo_info`
     /// (e.g. the exact Algo variant can have a different size for e, in RSA;
     /// also, the import_format can differ).
-    pub(crate) fn determine_algo(
+    pub(crate) fn determine_algo_attributes(
         &self,
         key_type: KeyType,
         ard: &ApplicationRelatedData,
         algo_info: Option<AlgoInfo>,
-    ) -> Result<AlgorithmAttributes, crate::Error> {
+    ) -> Result<AlgorithmAttributes, Error> {
         let algo = match self {
-            Self::RSA1k => {
-                AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(1024, key_type, ard, algo_info)?)
-            }
-            Self::RSA2k => {
-                AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(2048, key_type, ard, algo_info)?)
-            }
-            Self::RSA3k => {
-                AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(3072, key_type, ard, algo_info)?)
-            }
-            Self::RSA4k => {
-                AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(4096, key_type, ard, algo_info)?)
-            }
+            Self::RSA1k => AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(
+                1024,
+                key_type,
+                ard.algorithm_attributes(key_type)?,
+                algo_info,
+            )?),
+            Self::RSA2k => AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(
+                2048,
+                key_type,
+                ard.algorithm_attributes(key_type)?,
+                algo_info,
+            )?),
+            Self::RSA3k => AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(
+                3072,
+                key_type,
+                ard.algorithm_attributes(key_type)?,
+                algo_info,
+            )?),
+            Self::RSA4k => AlgorithmAttributes::Rsa(keys::determine_rsa_attrs(
+                4096,
+                key_type,
+                ard.algorithm_attributes(key_type)?,
+                algo_info,
+            )?),
             Self::NIST256 => AlgorithmAttributes::Ecc(keys::determine_ecc_attrs(
                 Curve::NistP256r1.oid(),
                 Self::ecc_type(key_type),
@@ -334,7 +346,7 @@ impl Curve {
 }
 
 impl TryFrom<&[u8]> for Curve {
-    type Error = crate::Error;
+    type Error = Error;
 
     fn try_from(oid: &[u8]) -> Result<Self, Self::Error> {
         use Curve::*;

openpgp-card/src/keys.rs

@@ -9,7 +9,7 @@ use std::time::{SystemTime, UNIX_EPOCH};
 use crate::algorithm::{AlgoInfo, AlgorithmAttributes, Curve, EccAttrs, RsaAttrs};
 use crate::apdu::command::Command;
 use crate::apdu::commands;
-use crate::card_do::{ApplicationRelatedData, Fingerprint, KeyGenerationTime};
+use crate::card_do::{Fingerprint, KeyGenerationTime};
 use crate::crypto_data::{
     CardUploadableKey, EccKey, EccPub, EccType, PrivateKeyMaterial, PublicKeyMaterial, RSAKey,
     RSAPub,
@@ -189,7 +189,8 @@ pub(crate) fn key_import(
             // (round up to 4-bytes, in case the key has 8+ leading zero bits)
             let rsa_bits = (((rsa_key.n().len() * 8 + 31) / 32) * 32) as u16;
 
-            let rsa_attrs = determine_rsa_attrs(rsa_bits, key_type, &ard, algo_info)?;
+            let algo_attr = ard.algorithm_attributes(key_type)?;
+            let rsa_attrs = determine_rsa_attrs(rsa_bits, key_type, algo_attr, algo_info)?;
 
             let key_cmd = rsa_key_import_cmd(key_type, rsa_key, &rsa_attrs)?;
 
@@ -233,9 +234,9 @@ pub(crate) fn key_import(
 pub(crate) fn determine_rsa_attrs(
     rsa_bits: u16,
     key_type: KeyType,
-    ard: &ApplicationRelatedData,
+    algo_attr: AlgorithmAttributes,
     algo_info: Option<AlgoInfo>,
-) -> Result<RsaAttrs, crate::Error> {
+) -> Result<RsaAttrs, Error> {
     // Figure out suitable RSA algorithm parameters:
 
     // Does the card offer a list of algorithms?
@@ -246,10 +247,8 @@ pub(crate) fn determine_rsa_attrs(
     } else {
         // No -> Get the current algorithm attributes for key_type.
 
-        let algo = ard.algorithm_attributes(key_type)?;
-
         // Is the algorithm on the card currently set to RSA?
-        if let AlgorithmAttributes::Rsa(rsa) = algo {
+        if let AlgorithmAttributes::Rsa(rsa) = algo_attr {
             // If so, use the algorithm parameters from the card and
             // adjust the bit length based on the user-provided key.
             RsaAttrs::new(rsa_bits, rsa.len_e(), rsa.import_format())

openpgp-card/src/openpgp.rs

@@ -1077,7 +1077,7 @@ impl<'a> OpenPgpTransaction<'a> {
     // -----------------
 
     /// Import an existing private key to the card.
-    /// (This implicitly sets the algorithm info, fingerprint and timestamp)
+    /// (This implicitly sets the algorithm attributes, fingerprint and timestamp)
     pub fn key_import(
         &mut self,
         key: Box<dyn CardUploadableKey>,
@@ -1093,10 +1093,10 @@ impl<'a> OpenPgpTransaction<'a> {
     /// Generate a key on the card.
     /// (7.2.14 GENERATE ASYMMETRIC KEY PAIR)
     ///
-    /// If the `algo` parameter is Some, then this algorithm will be set on
+    /// If the `algorithm_attributes` parameter is Some, then this algorithm will be set on
     /// the card for "key_type".
     ///
-    /// Note: `algo` needs to precisely specify the RSA bitsize of e (if
+    /// Note: `algorithm_attributes` needs to precisely specify the RSA bitsize of e (if
     /// applicable), and import format, with values that the current card
     /// supports.
     pub fn generate_key(
@@ -1107,9 +1107,9 @@ impl<'a> OpenPgpTransaction<'a> {
             KeyType,
         ) -> Result<Fingerprint, Error>,
         key_type: KeyType,
-        algo: Option<&AlgorithmAttributes>,
+        algorithm_attributes: Option<&AlgorithmAttributes>,
     ) -> Result<(PublicKeyMaterial, KeyGenerationTime), Error> {
-        keys::gen_key_with_metadata(self, fp_from_pub, key_type, algo)
+        keys::gen_key_with_metadata(self, fp_from_pub, key_type, algorithm_attributes)
     }
 
     /// Generate a key on the card.
@@ -1138,7 +1138,7 @@ impl<'a> OpenPgpTransaction<'a> {
             None
         };
 
-        let algo = simple.determine_algo(key_type, &ard, algo_info)?;
+        let algo = simple.determine_algo_attributes(key_type, &ard, algo_info)?;
 
         Self::generate_key(self, fp_from_pub, key_type, Some(&algo))
     }