Don't return ASCII control characters in HTTP error messages

diff --git a/lightning-block-sync/src/http.rs b/lightning-block-sync/src/http.rs
index 154afa4889c7b7b9e263eac22cf6f5e5aff0bfd2..2e70e18659936e2746638ba684b36ce20c3095ca 100644 (file)
--- a/lightning-block-sync/src/http.rs
+++ b/lightning-block-sync/src/http.rs
@@ -348,9 +348,11 @@ impl HttpClient {
 
                if !status.is_ok() {
                        // TODO: Handle 3xx redirection responses.
-                       let error_details = match contents.is_ascii() {
-                               true => String::from_utf8_lossy(&contents).to_string(),
-                               false => "binary".to_string()
+                       let error_details = match String::from_utf8(contents) {
+                               // Check that the string is all-ASCII with no control characters before returning
+                               // it.
+                               Ok(s) if s.as_bytes().iter().all(|c| c.is_ascii() && !c.is_ascii_control()) => s,
+                               _ => "binary".to_string()
                        };
                        let error_msg = format!("Errored with status: {} and contents: {}",
                                                status.code, error_details);