rust: Mirror TROVE-2018-005 fix in Rust protover implementation.

 * REFACTORS `UnvalidatedProtoEntry::from_str` to place the bulk of the
   splitting/parsing logic in to a new
   `UnvalidatedProtoEntry::parse_protocol_and_version_str()` method (so that
   both `from_str()` and `from_str_any_len()` can call it.)
 * ADD a new `UnvalidatedProtoEntry::from_str_any_len()` method in order to
   maintain compatibility with consensus methods older than 29.
 * ADD a limit on the number of characters in a protocol name.
 * FIXES part of #25517: https://bugs.torproject.org/25517

1 files changed, 10 insertions, 4 deletions

diff --git a/src/rust/protover/ffi.rs b/src/rust/protover/ffi.rs
index 2dfeda87b2..1e0d9d6bff 100644
--- a/src/rust/protover/ffi.rs
+++ b/src/rust/protover/ffi.rs
@@ -56,7 +56,8 @@ pub extern "C" fn protover_all_supported(
         Err(_) => return 1,
     };
 
-    let relay_proto_entry: UnvalidatedProtoEntry = match relay_version.parse() {
+    let relay_proto_entry: UnvalidatedProtoEntry =
+        match UnvalidatedProtoEntry::from_str_any_len(relay_version) {
         Ok(n)  => n,
         Err(_) => return 1,
     };
@@ -167,6 +168,7 @@ pub extern "C" fn protover_get_supported_protocols() -> *const c_char {
 pub extern "C" fn protover_compute_vote(
     list: *const Stringlist,
     threshold: c_int,
+    allow_long_proto_names: bool,
 ) -> *mut c_char {
 
     if list.is_null() {
@@ -181,9 +183,13 @@ pub extern "C" fn protover_compute_vote(
     let mut proto_entries: Vec<UnvalidatedProtoEntry> = Vec::new();
 
     for datum in data {
-        let entry: UnvalidatedProtoEntry = match datum.parse() {
-            Ok(x)  => x,
-            Err(_) => continue,
+        let entry: UnvalidatedProtoEntry = match allow_long_proto_names {
+            true => match UnvalidatedProtoEntry::from_str_any_len(datum.as_str()) {
+                Ok(n)  => n,
+                Err(_) => continue},
+            false => match datum.parse() {
+                Ok(n)  => n,
+                Err(_) => continue},
         };
         proto_entries.push(entry);
     }