From 90bf9b690258d496b03c4e86580afa1dd6ea7784 Mon Sep 17 00:00:00 2001
From: Aaron Turon <aturon@fastly.com>
Date: Wed, 1 Dec 2021 10:15:29 -0800
Subject: [PATCH] Tighten privacy on read-only session fields

---
 lib/src/session.rs    | 25 ++++++++++++++++++++-----
 lib/src/wiggle_abi.rs |  6 +++---
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/lib/src/session.rs b/lib/src/session.rs
index 397b6a9a..8a90b89a 100644
--- a/lib/src/session.rs
+++ b/lib/src/session.rs
@@ -64,15 +64,15 @@ pub struct Session {
     /// The backends configured for this execution.
     ///
     /// Populated prior to guest execution, and never modified.
-    pub(crate) backends: Arc<Backends>,
+    backends: Arc<Backends>,
     /// The TLS configuration for this execution.
     ///
     /// Populated prior to guest execution, and never modified.
-    pub(crate) tls_config: Arc<rustls::ClientConfig>,
+    tls_config: Arc<rustls::ClientConfig>,
     /// The dictionaries configured for this execution.
     ///
     /// Populated prior to guest execution, and never modified.
-    pub(crate) dictionaries: Arc<Dictionaries>,
+    dictionaries: Arc<Dictionaries>,
     /// The dictionaries configured for this execution.
     ///
     /// Populated prior to guest execution, and never modified.
@@ -80,7 +80,7 @@ pub struct Session {
     /// The path to the configuration file used for this invocation of Viceroy.
     ///
     /// Created prior to guest execution, and never modified.
-    pub(crate) config_path: Arc<Option<PathBuf>>,
+    config_path: Arc<Option<PathBuf>>,
     /// The ID for the client request being processed.
     req_id: u64,
 }
@@ -520,9 +520,14 @@ impl Session {
         self.backends.get(name).map(std::ops::Deref::deref)
     }
 
+    /// Access the backend map.
+    pub fn backends(&self) -> &Arc<Backends> {
+        &self.backends
+    }
+
     // ----- TLS config -----
 
-    /// Reference the TLS configuration.
+    /// Access the TLS configuration.
     pub fn tls_config(&self) -> &Arc<rustls::ClientConfig> {
         &self.tls_config
     }
@@ -543,6 +548,11 @@ impl Session {
             .ok_or(HandleError::InvalidDictionaryHandle(handle))
     }
 
+    /// Access the dictionary map.
+    pub fn dictionaries(&self) -> &Arc<Dictionaries> {
+        &self.dictionaries
+    }
+
     // ----- Pending Requests API -----
 
     /// Insert a [`PendingRequest`] into the session.
@@ -641,6 +651,11 @@ impl Session {
     pub fn req_id(&self) -> u64 {
         self.req_id
     }
+
+    /// Access the path to the configuration file for this invocation.
+    pub fn config_path(&self) -> &Arc<Option<PathBuf>> {
+        &self.config_path
+    }
 }
 
 #[derive(Clone, Copy, Eq, Hash, PartialEq)]
diff --git a/lib/src/wiggle_abi.rs b/lib/src/wiggle_abi.rs
index 6d000460..4cda6cff 100644
--- a/lib/src/wiggle_abi.rs
+++ b/lib/src/wiggle_abi.rs
@@ -107,9 +107,9 @@ impl UserErrorConversion for Session {
     fn fastly_status_from_error(&mut self, e: Error) -> Result<FastlyStatus, wiggle::Trap> {
         match e {
             Error::UnknownBackend(ref backend) => {
-                let config_path = &self.config_path;
-                let backends_buffer = itertools::join(self.backends.keys(), ",");
-                let backends_len = self.backends.len();
+                let config_path = &self.config_path();
+                let backends_buffer = itertools::join(self.backends().keys(), ",");
+                let backends_len = self.backends().len();
 
                 match (backends_len, (**config_path).as_ref()) {
                     (_, None) => event!(