88 lines
3 KiB
Rust
88 lines
3 KiB
Rust
use infer::MatcherType;
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/// Returns a Content-Disposition of `attachment` or `inline`, depending on the
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/// *parsed* contents of the file uploaded via format magic keys using `infer`
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/// crate (basically libmagic without needing libmagic).
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///
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/// This forbids trusting what the client or remote server says the file is from
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/// their `Content-Type` and we try to detect it ourselves. Also returns
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/// `attachment` if the Content-Type does not match what we detected.
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///
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/// TODO: add a "strict" function for comparing the Content-Type with what we
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/// detected: `file_type.mime_type() != content_type`
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pub(crate) fn content_disposition_type(buf: &[u8], _content_type: &Option<String>) -> &'static str {
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let Some(file_type) = infer::get(buf) else {
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return "attachment";
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};
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match file_type.matcher_type() {
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MatcherType::IMAGE | MatcherType::AUDIO | MatcherType::TEXT | MatcherType::VIDEO => "inline",
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_ => "attachment",
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}
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}
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/// sanitises the file name for the Content-Disposition using
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/// `sanitize_filename` crate
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#[tracing::instrument]
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pub(crate) fn sanitise_filename(filename: String) -> String {
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let options = sanitize_filename::Options {
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truncate: false,
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..Default::default()
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};
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sanitize_filename::sanitize_with_options(filename, options)
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}
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/// creates the final Content-Disposition based on whether the filename exists
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/// or not.
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///
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/// if filename exists: `Content-Disposition: attachment/inline;
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/// filename=filename.ext` else: `Content-Disposition: attachment/inline`
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#[tracing::instrument(skip(file))]
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pub(crate) fn make_content_disposition(
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file: &[u8], content_type: &Option<String>, content_disposition: Option<String>,
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) -> String {
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let filename = content_disposition.map_or_else(String::new, |content_disposition| {
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let (_, filename) = content_disposition
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.split_once("filename=")
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.unwrap_or(("", ""));
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if filename.is_empty() {
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String::new()
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} else {
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sanitise_filename(filename.to_owned())
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}
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});
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if !filename.is_empty() {
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// Content-Disposition: attachment/inline; filename=filename.ext
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format!("{}; filename={}", content_disposition_type(file, content_type), filename)
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} else {
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// Content-Disposition: attachment/inline
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String::from(content_disposition_type(file, content_type))
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}
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}
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#[cfg(test)]
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mod tests {
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#[test]
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fn string_sanitisation() {
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const SAMPLE: &str =
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"🏳️⚧️this\\r\\n įs \r\\n ä \\r\nstrïng 🥴that\n\r ../../../../../../../may be\r\n malicious🏳️⚧️";
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const SANITISED: &str = "🏳️⚧️thisrn įs n ä rstrïng 🥴that ..............may be malicious🏳️⚧️";
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let options = sanitize_filename::Options {
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windows: true,
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truncate: true,
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replacement: "",
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};
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// cargo test -- --nocapture
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println!("{}", SAMPLE);
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println!("{}", sanitize_filename::sanitize_with_options(SAMPLE, options.clone()));
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println!("{:?}", SAMPLE);
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println!("{:?}", sanitize_filename::sanitize_with_options(SAMPLE, options.clone()));
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assert_eq!(SANITISED, sanitize_filename::sanitize_with_options(SAMPLE, options.clone()));
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}
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}
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