lighthouse/common/warp_utils/src/cors.rs
Paul Hauner a3704b971e Support pre-flight CORS check (#1772)
## Issue Addressed

- Resolves #1766 

## Proposed Changes

- Use the `warp::filters::cors` filter instead of our work-around.

## Additional Info

It's not trivial to enable/disable `cors` using `warp`, since using `routes.with(cors)` changes the type of `routes`.  This makes it difficult to apply/not apply cors at runtime. My solution has been to *always* use the `warp::filters::cors` wrapper but when cors should be disabled, just pass the HTTP server listen address as the only permissible origin.
2020-10-22 04:47:27 +00:00

77 lines
2.4 KiB
Rust

use std::net::Ipv4Addr;
use warp::filters::cors::Builder;
/// Configure a `cors::Builder`.
///
/// If `allow_origin.is_none()` the `default_origin` is used.
pub fn set_builder_origins(
builder: Builder,
allow_origin: Option<&str>,
default_origin: (Ipv4Addr, u16),
) -> Result<Builder, String> {
if let Some(allow_origin) = allow_origin {
let origins = allow_origin
.split(',')
.map(|s| verify_cors_origin_str(s).map(|_| s))
.collect::<Result<Vec<_>, _>>()?;
Ok(builder.allow_origins(origins))
} else {
let origin = format!("http://{}:{}", default_origin.0, default_origin.1);
verify_cors_origin_str(&origin)?;
Ok(builder.allow_origin(origin.as_str()))
}
}
/// Verify that `s` can be used as a CORS origin.
///
/// ## Notes
///
/// We need this function since `warp` will panic if provided an invalid origin. The verification
/// code is taken from here:
///
/// https://github.com/seanmonstar/warp/blob/3d1760c6ca35ce2d03dee0562259d0320e9face3/src/filters/cors.rs#L616
///
/// Ideally we should make a PR to `warp` to expose this behaviour, however we defer this for a
/// later time. The impact of a false-positive on this function is fairly limited, since only
/// trusted users should be setting CORS origins.
fn verify_cors_origin_str(s: &str) -> Result<(), String> {
// Always the wildcard origin.
if s == "*" {
return Ok(());
}
let mut parts = s.splitn(2, "://");
let scheme = parts
.next()
.ok_or_else(|| format!("{} is missing a scheme", s))?;
let rest = parts
.next()
.ok_or_else(|| format!("{} is missing the part following the scheme", s))?;
headers::Origin::try_from_parts(scheme, rest, None)
.map_err(|e| format!("Unable to parse {}: {}", s, e))
.map(|_| ())
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn valid_origins() {
verify_cors_origin_str("*").unwrap();
verify_cors_origin_str("http://127.0.0.1").unwrap();
verify_cors_origin_str("http://localhost").unwrap();
verify_cors_origin_str("http://127.0.0.1:8000").unwrap();
verify_cors_origin_str("http://localhost:8000").unwrap();
}
#[test]
fn invalid_origins() {
verify_cors_origin_str(".*").unwrap_err();
verify_cors_origin_str("127.0.0.1").unwrap_err();
verify_cors_origin_str("localhost").unwrap_err();
}
}