From 3a25914ec59953db583dee86a5d87bd75eeedc1d Mon Sep 17 00:00:00 2001
From: Nathan Fisher <nfisher.sr@gmail.com>
Date: Fri, 23 Jun 2023 00:13:56 -0400
Subject: [PATCH] Added `create_folder` method to `MailStore` trait; Add code
 to set restrictive permissions on mail account folders;

---
 Cargo.toml                  |  6 ++++++
 src/mailstore/filesystem.rs | 36 +++++++++++++++++++++++++++++++++++-
 src/mailstore/mod.rs        | 15 +++++++++++++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index ccb1196..b41579c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 digest = "0.10"
+libc = "0.2.146"
 rustls-pemfile = "1.0"
 sha2 = "0.10"
 time = "0.3"
@@ -12,6 +13,11 @@ x509-parser = "0.15"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[dependencies.pw]
+git = "https://codeberg.org/jeang3nie/pw_rs.git"
+default-features = false
+features = [ "libc" ]
+
 [dependencies.rustls]
 version = "0.21"
 features = [ "dangerous_configuration" ]
diff --git a/src/mailstore/filesystem.rs b/src/mailstore/filesystem.rs
index f671572..470d124 100644
--- a/src/mailstore/filesystem.rs
+++ b/src/mailstore/filesystem.rs
@@ -1,4 +1,8 @@
-use std::io::BufReader;
+use std::{
+    ffi::CString,
+    io::BufReader,
+    os::{fd::AsRawFd, unix::prelude::OpenOptionsExt},
+};
 
 use crate::prelude::Certificate;
 
@@ -149,6 +153,21 @@ impl MailStore for Filesystem {
         Some(folder)
     }
 
+    fn create_folder(&self, user: &str, folder: &str) -> Result<(), io::Error> {
+        if self.has_mailuser(user) {
+            let user: Mailbox = user.parse().map_err(|e: ParseMailboxError| {
+                io::Error::new(io::ErrorKind::Other, e.to_string())
+            })?;
+            let user: Mailuser = user.into();
+            let mut path = self.path.clone();
+            path.push(&user.host.to_string());
+            path.push(&user.username);
+            path.push(folder);
+            fs::create_dir_all(&path)?;
+        }
+        Ok(())
+    }
+
     fn get_message(&self, user: &str, folder: &str, id: &str) -> Option<Message> {
         self.get_folder(user, folder)
             .and_then(|f| f.messages.get(id).cloned())
@@ -230,7 +249,22 @@ impl MailStore for Filesystem {
                 .create(true)
                 .write(true)
                 .truncate(true)
+                .mode(0o2770)
                 .open(path)?;
+            if let Some(pw) = pw::Passwd::getpw()
+                .map_err(|e: pw::Error| io::Error::new(io::ErrorKind::Other, e.to_string()))?
+            {
+                let groups = pw
+                    .groups()
+                    .map_err(|e: pw::Error| io::Error::new(io::ErrorKind::Other, e.to_string()))?;
+                if let Some(gr) = groups.iter().find(|g| g.name == mb.username) {
+                    unsafe {
+                        if libc::fchown(fd.as_raw_fd(), pw.uid, gr.gid) != 0 {
+                            return Err(io::Error::last_os_error());
+                        }
+                    }
+                }
+            }
             let mut writer = BufWriter::new(fd);
             writer.write_all(blurb.as_bytes())?;
         }
diff --git a/src/mailstore/mod.rs b/src/mailstore/mod.rs
index e146168..7b2b4b4 100644
--- a/src/mailstore/mod.rs
+++ b/src/mailstore/mod.rs
@@ -19,6 +19,8 @@ pub trait MailStore {
     fn has_mailuser(&self, mailuser: &str) -> bool;
     /// Retreives all of the messages for this user
     fn get_folder(&self, user: &str, folder: &str) -> Option<Folder>;
+    /// Creates a folder for the specified user, if it doesn't already exist
+    fn create_folder(&self, user: &str, folder: &str) -> Result<(), Self::Error>;
     /// Checks whether this server has a message with the given title for this user and if so
     /// returns the message
     fn get_message(&self, user: &str, folder: &str, id: &str) -> Option<Message>;
@@ -97,6 +99,19 @@ impl MailStore for Domain {
             .and_then(|u| u.folders.get(folder).cloned())
     }
 
+    fn create_folder(&self, user: &str, folder: &str) -> Result<(), io::Error> {
+        self.users.get(user).cloned().and_then(|mut u| {
+            u.folders.insert(
+                folder.to_string(),
+                Folder {
+                    name: folder.to_string(),
+                    messages: HashMap::new(),
+                },
+            )
+        });
+        Ok(())
+    }
+
     fn get_message(&self, user: &str, folder: &str, title: &str) -> Option<Message> {
         self.users
             .get(user)