From bfd5e12bea38a645453da8daecfeac5c0ae3d910 Mon Sep 17 00:00:00 2001
From: Bill Thiede <git@xinu.tv>
Date: Mon, 22 Jul 2024 16:39:59 -0700
Subject: [PATCH] Make URL joining more robust

---
 server/src/lib.rs        | 46 +++++++++++++++++++++++-----------------
 server/src/newsreader.rs | 25 +++++++++++-----------
 server/src/nm.rs         |  2 +-
 3 files changed, 40 insertions(+), 33 deletions(-)

diff --git a/server/src/lib.rs b/server/src/lib.rs
index 6d65015..7b2018e 100644
--- a/server/src/lib.rs
+++ b/server/src/lib.rs
@@ -5,7 +5,7 @@ pub mod nm;
 
 use css_inline::{CSSInliner, InlineError, InlineOptions};
 use linkify::{LinkFinder, LinkKind};
-use log::error;
+use log::{error, info};
 use lol_html::{element, errors::RewritingError, rewrite_str, RewriteStrSettings};
 use maplit::{hashmap, hashset};
 use thiserror::Error;
@@ -50,31 +50,15 @@ pub fn linkify_html(text: &str) -> String {
 pub fn sanitize_html(
     html: &str,
     cid_prefix: &str,
-    base_url: &Url,
+    base_url: &Option<Url>,
 ) -> Result<String, SanitizeError> {
-    let element_content_handlers = vec![
+    let mut element_content_handlers = vec![
         // Open links in new tab
         element!("a[href]", |el| {
             el.set_attribute("target", "_blank").unwrap();
 
             Ok(())
         }),
-        // Make links with relative URLs absolute
-        element!("a[href]", |el| {
-            if let Some(Ok(href)) = el.get_attribute("href").map(|href| base_url.join(&href)) {
-                el.set_attribute("href", &href.as_str()).unwrap();
-            }
-
-            Ok(())
-        }),
-        // Make images with relative srcs absolute
-        element!("img[src]", |el| {
-            if let Some(Ok(src)) = el.get_attribute("src").map(|src| base_url.join(&src)) {
-                el.set_attribute("src", &src.as_str()).unwrap();
-            }
-
-            Ok(())
-        }),
         // Replace mixed part CID images with URL
         element!("img[src]", |el| {
             let src = el
@@ -98,6 +82,30 @@ pub fn sanitize_html(
             Ok(())
         }),
     ];
+    if let Some(base_url) = base_url {
+        element_content_handlers.extend(vec![
+            // Make links with relative URLs absolute
+            element!("a[href]", |el| {
+                if let Some(Ok(href)) = el.get_attribute("href").map(|href| {
+                    info!("href {href:?}");
+                    base_url.join(&href)
+                }) {
+                    el.set_attribute("href", &href.as_str()).unwrap();
+                }
+
+                Ok(())
+            }),
+            // Make images with relative srcs absolute
+            element!("img[src]", |el| {
+                if let Some(Ok(src)) = el.get_attribute("src").map(|src| base_url.join(&src)) {
+                    info!("src {src:?}");
+                    el.set_attribute("src", &src.as_str()).unwrap();
+                }
+
+                Ok(())
+            }),
+        ]);
+    }
 
     let inline_opts = InlineOptions {
         inline_style_tags: true,
diff --git a/server/src/newsreader.rs b/server/src/newsreader.rs
index ea227f2..dafd350 100644
--- a/server/src/newsreader.rs
+++ b/server/src/newsreader.rs
@@ -5,7 +5,6 @@ use std::{
 };
 
 use async_graphql::connection::{self, Connection, Edge};
-use log::info;
 use sqlx::postgres::PgPool;
 use url::Url;
 
@@ -185,18 +184,18 @@ pub async fn thread(pool: &PgPool, thread_id: String) -> Result<Thread, ServerEr
             })
             .unwrap_or(default_homepage.to_string()),
     )?;
-    let link = Url::parse(
-        &r.link
-            .as_ref()
-            .map(|h| {
-                if h.is_empty() {
-                    default_homepage.to_string()
-                } else {
-                    h.to_string()
-                }
-            })
-            .unwrap_or(default_homepage.to_string()),
-    )?;
+    let link = &r
+        .link
+        .as_ref()
+        .map(|h| {
+            if h.is_empty() {
+                default_homepage.to_string()
+            } else {
+                h.to_string()
+            }
+        })
+        .map(|h| Url::parse(&h).ok())
+        .flatten();
     let addr = r.link.as_ref().map(|link| {
         if link.contains('@') {
             link.clone()
diff --git a/server/src/nm.rs b/server/src/nm.rs
index 9e9a6d0..7c8a03f 100644
--- a/server/src/nm.rs
+++ b/server/src/nm.rs
@@ -179,7 +179,7 @@ pub async fn thread(
             .get_first_value("date")
             .and_then(|d| mailparse::dateparse(&d).ok());
         let cid_prefix = shared::urls::cid_prefix(None, &id);
-        let base_url = Url::parse("https://there-should-be-no-relative-urls-in-email").unwrap();
+        let base_url = None;
         let body = match extract_body(&m, &id)? {
             Body::PlainText(PlainText { text, content_tree }) => {
                 let text = if text.len() > MAX_RAW_MESSAGE_SIZE {