feat(client): add option to allow misplaced spaces in HTTP/1 responses (#2506)

src/client/client.rs

@@ -961,6 +961,31 @@ impl Builder {
         self
     }
 
+    /// Set whether HTTP/1 connections will accept spaces between header names
+    /// and the colon that follow them in responses.
+    ///
+    /// You probably don't need this, here is what [RFC 7230 Section 3.2.4.] has
+    /// to say about it:
+    ///
+    /// > No whitespace is allowed between the header field-name and colon. In
+    /// > the past, differences in the handling of such whitespace have led to
+    /// > security vulnerabilities in request routing and response handling. A
+    /// > server MUST reject any received request message that contains
+    /// > whitespace between a header field-name and colon with a response code
+    /// > of 400 (Bad Request). A proxy MUST remove any such whitespace from a
+    /// > response message before forwarding the message downstream.
+    ///
+    /// Note that this setting does not affect HTTP/2.
+    ///
+    /// Default is false.
+    ///
+    /// [RFC 7230 Section 3.2.4.]: https://tools.ietf.org/html/rfc7230#section-3.2.4
+    pub fn http1_allow_spaces_after_header_name_in_responses(&mut self, val: bool) -> &mut Self {
+        self.conn_builder
+            .h1_allow_spaces_after_header_name_in_responses(val);
+        self
+    }
+
     /// Set whether HTTP/1 connections will write header names as title case at
     /// the socket level.
     ///

src/client/conn.rs

@@ -56,6 +56,7 @@ use std::time::Duration;
 
 use bytes::Bytes;
 use futures_util::future::{self, Either, FutureExt as _};
+use httparse::ParserConfig;
 use pin_project::pin_project;
 use tokio::io::{AsyncRead, AsyncWrite};
 use tower_service::Service;
@@ -123,6 +124,7 @@ where
 pub struct Builder {
     pub(super) exec: Exec,
     h09_responses: bool,
+    h1_parser_config: ParserConfig,
     h1_title_case_headers: bool,
     h1_read_buf_exact_size: Option<usize>,
     h1_max_buf_size: Option<usize>,
@@ -496,6 +498,7 @@ impl Builder {
             exec: Exec::Default,
             h09_responses: false,
             h1_read_buf_exact_size: None,
+            h1_parser_config: Default::default(),
             h1_title_case_headers: false,
             h1_max_buf_size: None,
             #[cfg(feature = "http2")]
@@ -521,6 +524,14 @@ impl Builder {
         self
     }
 
+    pub(crate) fn h1_allow_spaces_after_header_name_in_responses(
+        &mut self,
+        enabled: bool,
+    ) -> &mut Builder {
+        self.h1_parser_config.allow_spaces_after_header_name_in_responses(enabled);
+        self
+    }
+
     pub(super) fn h1_title_case_headers(&mut self, enabled: bool) -> &mut Builder {
         self.h1_title_case_headers = enabled;
         self
@@ -704,6 +715,7 @@ impl Builder {
                 #[cfg(feature = "http1")]
                 Proto::Http1 => {
                     let mut conn = proto::Conn::new(io);
+                    conn.set_h1_parser_config(opts.h1_parser_config);
                     if opts.h1_title_case_headers {
                         conn.set_title_case_headers();
                     }