From e249f2f2c6b2fa277470a161f667fecd06649f4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sosth=C3=A8ne=20Gu=C3=A9don?= <sosthene@nitrokey.com>
Date: Wed, 29 Mar 2023 17:32:59 +0200
Subject: [PATCH] Add reading of large data objects

---
 Cargo.toml   |  2 +-
 src/lib.rs   | 13 +++++++----
 src/state.rs | 66 ++++++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 72 insertions(+), 9 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 4bb1c0f..3763d61 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -74,7 +74,7 @@ log-warn = []
 log-error = []
 
 [patch.crates-io]
-trussed = { git = "https://github.com/Nitrokey/trussed", tag = "v0.1.0-nitrokey.8"}
+trussed = { git = "https://github.com/sosthene-nitrokey/trussed", rev = "25ae084251b76bacfa8919eb8"}
 trussed-auth = { git = "https://github.com/trussed-dev/trussed-auth", tag = "v0.2.1"}
 littlefs2 = { git = "https://github.com/Nitrokey/littlefs2", tag = "v0.3.2-nitrokey-2" }
 
diff --git a/src/lib.rs b/src/lib.rs
index a31b42b..debf3a0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -910,10 +910,15 @@ impl<'a, T: trussed::Client + AuthClient + trussed::client::Ed255> LoadedAuthent
         let offset = reply.len();
         match container {
             Container::KeyHistoryObject => self.get_key_history_object(reply.lend())?,
-            _ => match ContainerStorage(container).load(self.trussed, self.options.storage)? {
-                Some(data) => reply.expand(&data)?,
-                None => return Err(Status::NotFound),
-            },
+            _ => {
+                if !ContainerStorage(container).load(
+                    self.trussed,
+                    self.options.storage,
+                    reply.lend(),
+                )? {
+                    return Err(Status::NotFound);
+                }
+            }
         }
         reply.prepend_len(offset)?;
 
diff --git a/src/state.rs b/src/state.rs
index 93c145e..b2cf0f3 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -8,6 +8,7 @@ use flexiber::EncodableHeapless;
 use heapless::Vec;
 use heapless_bytes::Bytes;
 use iso7816::Status;
+use trussed::types::OpenSeekFrom;
 use trussed::{
     api::reply::Metadata,
     config::MAX_MESSAGE_LENGTH,
@@ -17,6 +18,7 @@ use trussed::{
 use trussed_auth::AuthClient;
 
 use crate::piv_types::CardHolderUniqueIdentifier;
+use crate::reply::Reply;
 use crate::{constants::*, piv_types::AsymmetricAlgorithms};
 use crate::{
     container::{AsymmetricKeyReference, Container, ReadAccessRule, SecurityCondition},
@@ -617,6 +619,53 @@ fn load_if_exists(
     }
 }
 
+/// Returns false if the file does not exist
+fn load_if_exists_streaming<const R: usize>(
+    client: &mut impl trussed::Client,
+    location: Location,
+    path: &PathBuf,
+    mut buffer: Reply<'_, R>,
+) -> Result<bool, Status> {
+    let mut read_len = 0;
+    let file_len;
+    match try_syscall!(client.read_file_chunk(location, path.clone(), OpenSeekFrom::Start(0))) {
+        Ok(r) => {
+            read_len += r.data.len();
+            file_len = r.len;
+            buffer.expand(&r.data)?;
+        }
+        Err(_) => match try_syscall!(client.entry_metadata(location, path.clone())) {
+            Ok(Metadata { metadata: None }) => return Ok(false),
+            Ok(Metadata {
+                metadata: Some(_metadata),
+            }) => {
+                error!("File {path} exists but couldn't be read: {_metadata:?}");
+                return Err(Status::UnspecifiedPersistentExecutionError);
+            }
+            Err(_err) => {
+                error!("File {path} couldn't be read: {_err:?}");
+                return Err(Status::UnspecifiedPersistentExecutionError);
+            }
+        },
+    }
+
+    while read_len < file_len {
+        match try_syscall!(client.read_file_chunk(
+            location,
+            path.clone(),
+            OpenSeekFrom::Start(read_len as u32)
+        )) {
+            Ok(r) => {
+                read_len += r.data.len();
+                buffer.expand(&r.data)?;
+            }
+            Err(_err) => error!("Failed to read chunk: {:?}", _err),
+        }
+    }
+
+    Ok(true)
+}
+
 #[derive(Clone, Copy, Debug)]
 pub struct ContainerStorage(pub Container);
 
@@ -703,13 +752,22 @@ impl ContainerStorage {
         }
     }
 
-    pub fn load(
+    pub fn load<const R: usize>(
         self,
         client: &mut impl trussed::Client,
         storage: Location,
-    ) -> Result<Option<Bytes<MAX_MESSAGE_LENGTH>>, Status> {
-        load_if_exists(client, storage, &self.path())
-            .map(|data| data.or_else(|| self.default().map(Bytes::from)))
+        mut reply: Reply<'_, R>,
+    ) -> Result<bool, Status> {
+        if load_if_exists_streaming(client, storage, &self.path(), reply.lend())? {
+            return Ok(true);
+        }
+
+        if let Some(data) = self.default() {
+            reply.expand(&data)?;
+            Ok(true)
+        } else {
+            Ok(false)
+        }
     }
 
     pub fn save(