From 0b05b7247dc42dc52703d0294c03b9c96e51ba6b Mon Sep 17 00:00:00 2001
From: Ron Waldon-Howe <jokeyrhyme@jokeyrhy.me>
Date: Sat, 16 Nov 2024 11:39:47 +1100
Subject: [PATCH] =?UTF-8?q?=F0=9F=A6=BA=20`send=5Fdestination`=20XOR=20`se?=
 =?UTF-8?q?nd=5Fdestination=5Fprefix`?=
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https://github.com/dbus2/busd/pull/159#discussion_r1842115184
---
 src/config.rs | 75 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 61 insertions(+), 14 deletions(-)

diff --git a/src/config.rs b/src/config.rs
index 32c87f6..0b1f1e0 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -76,6 +76,15 @@ pub struct Config {
     pub user: Option<String>,
 }
 
+#[derive(Clone, Debug, Deserialize, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub enum Destination {
+    #[serde(rename = "*")]
+    Any,
+    Name(String),
+    Prefix(String),
+}
+
 impl TryFrom<Document> for Config {
     type Error = Error;
 
@@ -297,6 +306,10 @@ impl TryFrom<RuleAttributes> for OptionalOperation {
             .map(i8::from)
             .sum();
 
+        if value.send_destination.is_some() && value.send_destination_prefix.is_some() {
+            return Err(Error::msg(format!("send_destination_prefix cannot be combined with the send_destination in the same rule: {value:?}")));
+        }
+
         if operations_count > 1 {
             return Err(Error::msg(format!("do not mix rule attributes for connect, own, receive, and/or send operations in the same rule: {value:?}")));
         }
@@ -534,8 +547,7 @@ pub type Rule = (Access, Operation);
 #[derive(Clone, Debug, Deserialize, PartialEq)]
 pub struct SendOperation {
     pub broadcast: Option<bool>,
-    pub destination: String,
-    pub destination_prefix: String,
+    pub destination: Option<Destination>,
     pub error: String,
     pub interface: String,
     pub max_fds: u32,
@@ -547,8 +559,7 @@ impl Default for SendOperation {
     fn default() -> Self {
         Self {
             broadcast: None,
-            destination: String::from("*"),
-            destination_prefix: String::default(),
+            destination: None,
             error: String::from("*"),
             interface: String::from("*"),
             max_fds: u32::MAX,
@@ -560,10 +571,27 @@ impl Default for SendOperation {
 }
 impl From<RuleAttributes> for SendOperation {
     fn from(value: RuleAttributes) -> Self {
+        let destination = match value {
+            RuleAttributes {
+                send_destination: Some(some),
+                send_destination_prefix: None,
+                ..
+            } if some == "*" => Some(Destination::Any),
+            RuleAttributes {
+                send_destination: Some(some),
+                send_destination_prefix: None,
+                ..
+            } => Some(Destination::Name(some)),
+            RuleAttributes {
+                send_destination: None,
+                send_destination_prefix: Some(some),
+                ..
+            } => Some(Destination::Prefix(some)),
+            _ => None,
+        };
         Self {
             broadcast: value.send_broadcast,
-            destination: value.send_destination.unwrap_or(String::from("*")),
-            destination_prefix: value.send_destination_prefix.unwrap_or_default(),
+            destination,
             error: value.send_error.unwrap_or(String::from("*")),
             interface: value.send_interface.unwrap_or(String::from("*")),
             max_fds: value.max_fds.unwrap_or(u32::MAX),
@@ -769,7 +797,6 @@ mod tests {
                 <allow
                     send_broadcast="true"
                     send_destination="org.freedesktop.DBus"
-                    send_destination_prefix="org.freedesktop"
                     send_error="something bad"
                     send_interface="org.freedesktop.systemd1.Activator"
                     send_path="/org/freedesktop"
@@ -788,7 +815,7 @@ mod tests {
                     />
             </policy>
             <policy group="network">
-                <allow send_destination="org.freedesktop.Avahi" send_member="DoSomething" />
+                <allow send_destination_prefix="org.freedesktop" send_member="DoSomething" />
                 <allow receive_sender="org.freedesktop.Avahi" receive_member="DoSomething"/>
             </policy>
             <policy context="mandatory">
@@ -810,8 +837,9 @@ mod tests {
                                 Access::Allow,
                                 Operation::Send(SendOperation {
                                     broadcast: Some(true),
-                                    destination: String::from("org.freedesktop.DBus"),
-                                    destination_prefix: String::from("org.freedesktop"),
+                                    destination: Some(Destination::Name(String::from(
+                                        "org.freedesktop.DBus"
+                                    ))),
                                     error: String::from("something bad"),
                                     interface: String::from("org.freedesktop.systemd1.Activator"),
                                     max_fds: 128,
@@ -840,7 +868,9 @@ mod tests {
                             (
                                 Access::Allow,
                                 Operation::Send(SendOperation {
-                                    destination: String::from("org.freedesktop.Avahi"),
+                                    destination: Some(Destination::Prefix(String::from(
+                                        "org.freedesktop"
+                                    ))),
                                     ..Default::default()
                                 })
                             ),
@@ -858,7 +888,7 @@ mod tests {
                     Policy::MandatoryContext(vec![(
                         Access::Deny,
                         Operation::Send(SendOperation {
-                            destination: String::from("net.connman.iwd"),
+                            destination: Some(Destination::Name(String::from("net.connman.iwd"))),
                             ..Default::default()
                         })
                     ),]),
@@ -902,7 +932,7 @@ mod tests {
                             Access::Allow,
                             // `eavesdrop="true"` is dropped, keep other attributes
                             Operation::Send(SendOperation {
-                                destination: String::from("*"),
+                                destination: Some(Destination::Any),
                                 ..Default::default()
                             })
                         ),
@@ -915,7 +945,9 @@ mod tests {
                         (
                             Access::Allow,
                             Operation::Send(SendOperation {
-                                destination: String::from("org.gnome.DisplayManager"),
+                                destination: Some(Destination::Name(String::from(
+                                    "org.gnome.DisplayManager"
+                                ))),
                                 interface: String::from("org.gnome.DisplayManager.Manager"),
                                 // `member=... is dropped`
                                 ..Default::default()
@@ -929,6 +961,21 @@ mod tests {
         );
     }
 
+    #[should_panic]
+    #[test]
+    fn bus_config_parse_with_policies_with_send_destination_and_send_destination_prefix_error() {
+        let input = r#"<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
+        "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+        <busconfig>
+            <policy user="root">
+                <allow send_destination="org.freedesktop.DBus" send_destination_prefix="org.freedesktop" />
+            </policy>
+        </busconfig>
+        "#;
+
+        Config::parse(input).expect("should parse XML input");
+    }
+
     #[should_panic]
     #[test]
     fn bus_config_parse_with_policies_with_send_and_receive_attributes_error() {