mte/unikernel/duniverse/ocaml-tls/mirage/tls_mirage.ml
2025-11-11 02:07:51 +01:00

299 lines
10 KiB
OCaml

open Lwt.Infix
module Make (F : Mirage_flow.S) = struct
type error = [ `Tls_alert of Tls.Packet.alert_type
| `Tls_failure of Tls.Engine.failure
| `Read of F.error
| `Write of F.write_error ]
type write_error = [ Mirage_flow.write_error | error ]
let pp_error ppf = function
| `Tls_failure f -> Tls.Engine.pp_failure ppf f
| `Tls_alert a -> Fmt.string ppf @@ Tls.Packet.alert_type_to_string a
| `Read e -> F.pp_error ppf e
| `Write e -> F.pp_write_error ppf e
let pp_write_error ppf = function
| #Mirage_flow.write_error as e -> Mirage_flow.pp_write_error ppf e
| #error as e -> pp_error ppf e
type flow = {
role : [ `Server | `Client ] ;
flow : F.flow ;
mutable state : [ `Active of Tls.Engine.state
| `Read_closed of Tls.Engine.state
| `Write_closed of Tls.Engine.state
| `Closed
| `Error of error ] ;
mutable linger : string list ;
}
let half_close state mode =
match state, mode with
| `Active tls, `read -> `Read_closed tls
| `Active tls, `write -> `Write_closed tls
| `Active _, `read_write -> `Closed
| `Read_closed tls, `read -> `Read_closed tls
| `Read_closed _, (`write | `read_write) -> `Closed
| `Write_closed tls, `write -> `Write_closed tls
| `Write_closed _, (`read | `read_write) -> `Closed
| (`Closed | `Error _) as e, (`read | `write | `read_write) -> e
let inject_state tls = function
| `Active _ -> `Active tls
| `Read_closed _ -> `Read_closed tls
| `Write_closed _ -> `Write_closed tls
| (`Closed | `Error _) as e -> e
let tls_alert a = `Error (`Tls_alert a)
let tls_fail f = `Error (`Tls_failure f)
let write_flow flow buf =
F.write flow.flow (Cstruct.of_string buf) >>= function
| Ok _ as o -> Lwt.return o
| Error `Closed ->
flow.state <- half_close flow.state `write;
Lwt.return (Error (`Write `Closed))
| Error e ->
flow.state <- `Error (`Write e);
Lwt.return (Error (`Write e))
let read_react flow =
let handle tls buf =
match Tls.Engine.handle_tls tls buf with
| Ok (state, eof, `Response resp, `Data data) ->
let state = inject_state state flow.state in
let state = Option.(value ~default:state (map (fun `Eof -> half_close state `read) eof)) in
flow.state <- state;
( match resp with
| None -> Lwt.return @@ Ok ()
| Some buf -> write_flow flow buf) >>= fun _ ->
Lwt.return @@ `Ok (Option.map Cstruct.of_string data)
| Error (fail, `Response resp) ->
let reason = match fail with
| `Alert a -> tls_alert a
| f -> tls_fail f
in
flow.state <- reason ;
F.write flow.flow (Cstruct.of_string resp) >>= fun _ ->
Lwt.return reason
in
match flow.state with
| `Error _ as e -> Lwt.return e
| `Read_closed _ | `Closed -> Lwt.return `Eof
| `Active _ | `Write_closed _ ->
F.read flow.flow >>= function
| Error e ->
flow.state <- `Error (`Read e);
Lwt.return (`Error (`Read e))
| Ok `Eof ->
flow.state <- half_close flow.state `read;
Lwt.return `Eof
| Ok `Data buf -> match flow.state with
| `Active tls | `Write_closed tls -> handle tls (Cstruct.to_string buf)
| `Read_closed _ | `Closed -> Lwt.return `Eof
| `Error _ as e -> Lwt.return e
let rec read flow =
match flow.linger with
| [] ->
( read_react flow >>= function
| `Ok None -> read flow
| `Ok (Some buf) -> Lwt.return @@ Ok (`Data buf)
| `Eof -> Lwt.return @@ Ok `Eof
| `Error e -> Lwt.return @@ Error e )
| bufs ->
flow.linger <- [] ;
let str = String.concat "" (List.rev bufs) in
Lwt.return @@ Ok (`Data (Cstruct.of_string str))
let writev flow bufs =
match flow.state with
| `Closed | `Write_closed _ -> Lwt.return @@ Error `Closed
| `Error e -> Lwt.return @@ Error (e :> write_error)
| `Active tls | `Read_closed tls ->
let bufs = List.map Cstruct.to_string bufs in
match Tls.Engine.send_application_data tls bufs with
| Some (tls, answer) ->
flow.state <- `Active tls ;
write_flow flow answer
| None ->
(* "Impossible" due to handshake draining. *)
assert false
let write flow buf = writev flow [buf]
(*
* XXX bad XXX
* This is a point that should particularly be protected from concurrent r/w.
* Doing this before a `t` is returned is safe; redoing it during rekeying is
* not, as the API client already sees the `t` and can mistakenly interleave
* writes while this is in progress.
* *)
let rec drain_handshake flow =
match flow.state with
| `Active tls when not (Tls.Engine.handshake_in_progress tls) ->
Lwt.return @@ Ok flow
| _ ->
(* read_react re-throws *)
read_react flow >>= function
| `Ok mbuf ->
flow.linger <- Option.(to_list (map Cstruct.to_string mbuf)) @ flow.linger ;
drain_handshake flow
| `Error e -> Lwt.return @@ Error (e :> write_error)
| `Eof -> Lwt.return @@ Error `Closed
type wr_or_msg = [ write_error | `Msg of string ]
let underlying flow = flow.flow
let reneg ?authenticator ?acceptable_cas ?cert ?(drop = true) flow =
match flow.state with
| `Closed | `Write_closed _ | `Read_closed _ -> Lwt.return @@ Error `Closed
| `Error e -> Lwt.return @@ Error (e :> wr_or_msg)
| `Active tls ->
match Tls.Engine.reneg ?authenticator ?acceptable_cas ?cert tls with
| None -> Lwt.return (Error (`Msg "Renegotiation already in progress"))
| Some (tls', buf) ->
if drop then flow.linger <- [] ;
flow.state <- `Active tls' ;
write_flow flow buf >>= fun _ ->
drain_handshake flow >|= function
| Ok _ -> Ok ()
| Error e -> Error (e :> wr_or_msg)
let key_update ?request flow =
match flow.state with
| `Closed | `Write_closed _ -> Lwt.return @@ Error `Closed
| `Error e -> Lwt.return @@ Error (e :> wr_or_msg)
| `Active tls | `Read_closed tls ->
match Tls.Engine.key_update ?request tls with
| Error _ -> Lwt.return (Error (`Msg "Key update failed"))
| Ok (tls', buf) ->
flow.state <- `Active tls' ;
write_flow flow buf >|= function
| Ok _ as o -> o
| Error e -> Error (e :> wr_or_msg)
let close flow =
(match flow.state with
| `Active tls | `Read_closed tls ->
let tls, buf = Tls.Engine.send_close_notify tls in
flow.state <- inject_state tls flow.state;
flow.state <- `Closed;
write_flow flow buf >|= fun _ ->
()
| `Write_closed _ ->
flow.state <- `Closed;
Lwt.return_unit
| _ -> Lwt.return_unit) >>= fun () ->
F.close flow.flow
let shutdown flow mode =
match flow.state with
| `Active tls | `Read_closed tls | `Write_closed tls ->
let tls, buf =
match flow.state, mode with
| (`Active tls | `Read_closed tls), (`write | `read_write) ->
let tls, buf = Tls.Engine.send_close_notify tls in
tls, Some buf
| _, _ -> tls, None
in
flow.state <- inject_state tls (half_close flow.state mode);
(* as outlined above, this may fail since the TCP flow may already be (half-)closed *)
Option.fold
~none:Lwt.return_unit
~some:(fun b -> write_flow flow b >|= fun _ -> ())
buf >>= fun () ->
(match flow.state with
| `Closed -> F.close flow.flow
| _ -> Lwt.return_unit)
| `Error _ | `Closed ->
F.close flow.flow
let client_of_flow conf ?host flow =
let conf' = match host with
| None -> conf
| Some host -> Tls.Config.peer conf host
in
let (tls, init) = Tls.Engine.client conf' in
let tls_flow = {
role = `Client ;
flow = flow ;
state = `Active tls ;
linger = [] ;
} in
write_flow tls_flow init >>= fun _ ->
drain_handshake tls_flow
let server_of_flow conf flow =
let tls_flow = {
role = `Server ;
flow = flow ;
state = `Active (Tls.Engine.server conf) ;
linger = [] ;
} in
drain_handshake tls_flow
let epoch flow =
match flow.state with
| `Closed | `Error _ -> Error ()
| `Active tls | `Read_closed tls | `Write_closed tls -> Tls.Engine.epoch tls
(* let create_connection t tls_params host (addr, port) =
|+ XXX addr -> (host : string) +|
TCP.create_connection t (addr, port) >>= function
| `Error _ as e -> return e
| `Ok flow -> client_of_tcp_flow tls_params host flow *)
(* let listen_ssl t cert ~port callback =
let cb flow =
server_of_tcp_flow cert flow >>= callback in
TCP.input t ~listeners:(fun p -> if p = port then Some cb else None) *)
end
module X509 (KV : Mirage_kv.RO) = struct
let ca_roots_file = Mirage_kv.Key.v "ca-roots.crt"
let default_cert = "server"
let err_fail pp = function
| Ok x -> Lwt.return x
| Error e -> Fmt.kstr Lwt.fail_with "%a" pp e
let pp_msg ppf = function `Msg m -> Fmt.string ppf m
let decode_or_fail f cs = err_fail pp_msg (f cs)
let read kv name =
KV.get kv name >>= err_fail KV.pp_error >|= Cstruct.of_string
let read_crl kv = function
| None -> Lwt.return None
| Some filename ->
read kv (Mirage_kv.Key.v filename) >>= fun data ->
err_fail pp_msg (X509.CRL.decode_der (Cstruct.to_string data)) >|= fun crl ->
Some [ crl ]
let authenticator ?allowed_hashes ?crl kv =
let time () = Some (Mirage_ptime.now ()) in
let now = Mirage_ptime.now () in
read kv ca_roots_file >|= Cstruct.to_string >>=
decode_or_fail X509.Certificate.decode_pem_multiple >>= fun cas ->
let ta = X509.Validation.valid_cas ~time:now cas in
read_crl kv crl >|= fun crls ->
X509.Authenticator.chain_of_trust ?crls ?allowed_hashes ~time ta
let certificate kv =
let read name =
read kv (Mirage_kv.Key.v (name ^ ".pem")) >|= Cstruct.to_string >>=
decode_or_fail X509.Certificate.decode_pem_multiple >>= fun certs ->
read kv (Mirage_kv.Key.v (name ^ ".key")) >|= Cstruct.to_string >>=
decode_or_fail X509.Private_key.decode_pem >|= fun pk ->
(certs, pk)
in function | `Default -> read default_cert
| `Name name -> read name
end