Free the TLS connection state on close

CHANGELOG.md

@@ -6,6 +6,9 @@ All notable changes to this project will be documented in this file.
 
 - Added the `use_bundled_tls` build option. Applications can keep TLS enabled
   while replacing Dusty's pinned tls.zig dependency with a compatible module.
+- Server and client connections now call `tls.Connection.deinit` on close
+  when the TLS module declares one, so an injected module backed by a C
+  library (one `SSL` object per connection) does not leak per connection.
 - `Listener.kernel_backlog` now defaults to the system's limit, `net.core.somaxconn`
   on Linux, instead of 1024. A full accept queue makes Linux drop new connections,
   which then wait a second or more to retry.

src/client.zig

@@ -665,6 +665,14 @@ pub const Connection = struct {
     }
 
     pub fn deinit(self: *Connection) void {
+        if (build_options.use_tls) {
+            // See server.zig `Connection.deinit`: only a TLS module that owns
+            // per-connection state declares `deinit`.
+            if (@hasDecl(tls.Connection, "deinit")) {
+                if (self.tls_conn) |*c| c.deinit();
+            }
+            self.tls_conn = null;
+        }
         self.stream.close(self.io);
         if (self.protocol == .https) {
             self.allocator.free(self.tls_tcp_read_buffer);

src/server.zig

@@ -294,6 +294,15 @@ pub const Connection = struct {
     }
 
     pub fn deinit(self: *Connection) void {
+        if (build_options.use_tls) {
+            // tls.zig's Connection owns no memory and has no deinit; a TLS
+            // module backed by a C library (one SSL object per connection)
+            // frees it here.
+            if (@hasDecl(tls.Connection, "deinit")) {
+                if (self.tls_conn) |*c| c.deinit();
+            }
+            self.tls_conn = null;
+        }
         self.allocator.free(self.buffers);
     }