Improve server side html sanitization.

server/Cargo.toml

@@ -2,7 +2,7 @@
 name = "server"
 version = "0.1.0"
 edition = "2021"
-default-bin = "server"
+default-run = "server"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -24,6 +24,9 @@ memmap = "0.7.0"
 mailparse = "0.14.0"
 ammonia = "3.3.0"
 lol_html = "1.2.0"
+css-inline = "0.13.0"
+anyhow = "1.0.79"
+maplit = "1.0.2"
 
 [dependencies.rocket_contrib]
 version = "0.4.11"

server/src/bin/cleanhtml.rs

@@ -0,0 +1,16 @@
+use std::fs;
+
+use server::sanitize_html;
+
+fn main() -> anyhow::Result<()> {
+    let mut args = std::env::args().skip(1);
+    let src = args.next().expect("source not specified");
+    let dst = args.next().expect("destination not specified");
+    println!("Sanitizing {src} into {dst}");
+    let bytes = fs::read(src)?;
+    let html = String::from_utf8_lossy(&bytes);
+    let html = sanitize_html(&html)?;
+    fs::write(dst, html)?;
+
+    Ok(())
+}

server/src/graphql.rs

@@ -11,12 +11,13 @@ use async_graphql::{
     SimpleObject, Union,
 };
 use log::{error, info, warn};
-use lol_html::{element, errors::RewritingError, rewrite_str, RewriteStrSettings};
 use mailparse::{parse_mail, MailHeader, MailHeaderMap, ParsedMail};
 use memmap::MmapOptions;
 use notmuch::Notmuch;
 use rocket::time::Instant;
 
+use crate::sanitize_html;
+
 pub struct QueryRoot;
 
 /// # Number of seconds since the Epoch
@@ -190,25 +191,6 @@ struct Tag {
     bg_color: String,
     unread: usize,
 }
-fn sanitize_html(html: &str) -> Result<String, RewritingError> {
-    let element_content_handlers = vec![
-        // Open links in new tab
-        element!("a[href]", |el| {
-            el.set_attribute("target", "_blank").unwrap();
-
-            Ok(())
-        }),
-    ];
-
-    Ok(rewrite_str(
-        // TODO(wathiede): replace ammonia with more lol-html rules.
-        &ammonia::clean(&html),
-        RewriteStrSettings {
-            element_content_handlers,
-            ..RewriteStrSettings::default()
-        },
-    )?)
-}
 
 #[Object]
 impl QueryRoot {

server/src/lib.rs

@@ -1,3 +1,215 @@
 pub mod error;
 pub mod graphql;
 pub mod nm;
+
+use css_inline::{CSSInliner, InlineError, InlineOptions};
+use log::error;
+use lol_html::{element, errors::RewritingError, rewrite_str, RewriteStrSettings};
+use maplit::{hashmap, hashset};
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum SanitizeError {
+    #[error("lol-html rewrite error")]
+    RewritingError(#[from] RewritingError),
+    #[error("css inline error")]
+    InlineError(#[from] InlineError),
+}
+
+pub fn sanitize_html(html: &str) -> Result<String, SanitizeError> {
+    let element_content_handlers = vec![
+        // Open links in new tab
+        element!("a[href]", |el| {
+            el.set_attribute("target", "_blank").unwrap();
+
+            Ok(())
+        }),
+        // Only secure image URLs
+        element!("img[src]", |el| {
+            let src = el
+                .get_attribute("src")
+                .expect("src was required")
+                .replace("http:", "https:");
+
+            el.set_attribute("src", &src)?;
+
+            Ok(())
+        }),
+    ];
+
+    let inline_opts = InlineOptions {
+        inline_style_tags: true,
+        keep_style_tags: false,
+        keep_link_tags: false,
+        base_url: None,
+        load_remote_stylesheets: false,
+        extra_css: None,
+        preallocate_node_capacity: 32,
+        ..InlineOptions::default()
+    };
+
+    let inlined_html = match CSSInliner::new(inline_opts).inline(&html) {
+        Ok(inlined_html) => inlined_html,
+        Err(err) => {
+            error!("failed to inline CSS: {err}");
+            html.to_string()
+        }
+    };
+    // Default's don't allow style, but we want to preserve that.
+    let attributes =
+        hashset!["align", "bgcolor", "color", "height", "lang", "title", "width", "style",];
+
+    let tags = hashset![
+        "a",
+        "abbr",
+        "acronym",
+        "area",
+        "article",
+        "aside",
+        "b",
+        "bdi",
+        "bdo",
+        "blockquote",
+        "br",
+        "caption",
+        "center",
+        "cite",
+        "code",
+        "col",
+        "colgroup",
+        "data",
+        "dd",
+        "del",
+        "details",
+        "dfn",
+        "div",
+        "dl",
+        "dt",
+        "em",
+        "figcaption",
+        "figure",
+        "footer",
+        "h1",
+        "h2",
+        "h3",
+        "h4",
+        "h5",
+        "h6",
+        "header",
+        "hgroup",
+        "hr",
+        "i",
+        "img",
+        "ins",
+        "kbd",
+        "kbd",
+        "li",
+        "map",
+        "mark",
+        "nav",
+        "ol",
+        "p",
+        "pre",
+        "q",
+        "rp",
+        "rt",
+        "rtc",
+        "ruby",
+        "s",
+        "samp",
+        "small",
+        "span",
+        "strike",
+        "strong",
+        "sub",
+        "summary",
+        "sup",
+        "table",
+        "tbody",
+        "td",
+        "th",
+        "thead",
+        "time",
+        "title", // wathiede
+        "tr",
+        "tt",
+        "u",
+        "ul",
+        "var",
+        "wbr",
+    ];
+    let tag_attributes = hashmap![
+        "a" => hashset![
+            "href", "hreflang"
+        ],
+        "bdo" => hashset![
+            "dir"
+        ],
+        "blockquote" => hashset![
+            "cite"
+        ],
+        "col" => hashset![
+            "align", "char", "charoff", "span"
+        ],
+        "colgroup" => hashset![
+            "align", "char", "charoff", "span"
+        ],
+        "del" => hashset![
+            "cite", "datetime"
+        ],
+        "hr" => hashset![
+            "align", "size", "width"
+        ],
+        "img" => hashset![
+            "align", "alt", "height", "src", "width"
+        ],
+        "ins" => hashset![
+            "cite", "datetime"
+        ],
+        "ol" => hashset![
+            "start"
+        ],
+        "q" => hashset![
+            "cite"
+        ],
+        "table" => hashset![
+            "align", "border", "cellpadding", "cellspacing", "char", "charoff", "summary",
+        ],
+        "tbody" => hashset![
+            "align", "char", "charoff"
+        ],
+        "td" => hashset![
+            "align", "char", "charoff", "colspan", "headers", "rowspan"
+        ],
+        "tfoot" => hashset![
+            "align", "char", "charoff"
+        ],
+        "th" => hashset![
+            "align", "char", "charoff", "colspan", "headers", "rowspan", "scope"
+        ],
+        "thead" => hashset![
+            "align", "char", "charoff"
+        ],
+        "tr" => hashset![
+            "align", "char", "charoff"
+        ],
+    ];
+
+    let clean_html = ammonia::Builder::default()
+        .tags(tags)
+        .tag_attributes(tag_attributes)
+        .generic_attributes(attributes)
+        .clean(&inlined_html)
+        .to_string();
+    //let clean_html = inlined_html;
+
+    Ok(rewrite_str(
+        // TODO(wathiede): replace ammonia with more lol-html rules.
+        // &ammonia::clean(&html),
+        &clean_html,
+        RewriteStrSettings {
+            element_content_handlers,
+            ..RewriteStrSettings::default()
+        },
+    )?)
+}