MTE unikernel with Mkernel+Mnet+Vifu

This commit is contained in:
swrup 2026-03-11 14:17:52 +01:00 committed by Swrup
parent 76662bf23c
commit a23e59dfca
31 changed files with 535 additions and 376 deletions

View file

@ -1,8 +1,12 @@
(* TODO
! use lock
!? Scanf not thread-safe
schedule tasks
sign: check timestamps before signing
sign: check timestamps before signing *)
(* IMPROVE
Bin encode/decode
- catch failure
- should use little-endian
list_issue_date: save timestamp of key generation
key validity period:
more checks + do not exceed lookahead
@ -15,6 +19,8 @@ module Log = (val Logs.src_log src : Logs.LOG)
open Syntax
open Crypto
open Time
module Sfn = Mfat.Sfn
module Spath = Mfat.Spath
module Cfg = Config.Exchange_secmod_eddsa
type key = {
@ -25,74 +31,65 @@ type key = {
}
type t = {
sm_key_priv: EddsaPrivateKey.t;
fs: Fat.t;
sm_priv: EddsaPrivateKey.t;
sm_pub: EddsaPublicKey.t;
ht: (EddsaPublicKey.t, key) Hashtbl.t;
}
let parse_filename =
let scan_filename s =
Scanf.sscanf_opt s "%Lu-%Lu" (fun t1 t2 ->
(TimeAbsolute.of_s t1, TimeAbsolute.of_s t2))
in
fun fpath -> scan_filename (Fpath.filename fpath)
(* todo: this should be encoded in little-endian *)
let key_bin =
let open Bin in
record (fun t1 t2 priv ->
let pub = EddsaPrivateKey.pub_of_priv priv in
{ t1; t2; priv; pub })
|+ field TimeAbsolute.bin (fun t -> t.t1)
|+ field TimeAbsolute.bin (fun t -> t.t2)
|+ field EddsaPrivateKey.bin (fun t -> t.priv)
|> sealr
let pp_filename =
let to_int64 abs =
abs |> Timestamp.of_absolute |> Timestamp.to_s |> function
| None ->
(* (= `never`) this should not happen given resonable config value *)
Fmt.failwith "encountered timestamp with value `never`"
| Some i -> i
in
fun ppf (t1, t2) -> Fmt.pf ppf "%Lu-%Lu" (to_int64 t1) (to_int64 t2)
(* for sm_key only *)
let read_eddsa fs spath =
Log.debug (fun m -> m "reading key file `%a`" Spath.pp spath);
let* data = Fat.read fs spath |> unwrap_msg in
let* priv = EddsaPrivateKey.of_octets data in
let pub = EddsaPrivateKey.pub_of_priv priv in
Ok (priv, pub)
let key_fpath k =
let fname = Fmt.str "%a" pp_filename (k.t1, k.t2) in
Fpath.(v Cfg.key_dir / fname)
(* -- IO -- *)
let read_key fpath =
Log.debug (fun m -> m "reading key file `%a`" Fpath.pp fpath);
let* data = Bos.OS.File.read fpath |> unwrap_msg in
EddsaPrivateKey.of_octets data
let write_eddsa fpath priv =
Log.debug (fun m -> m "writing key file `%a`" Fpath.pp fpath);
let write_eddsa fs spath priv =
Log.debug (fun m -> m "writing key file `%a`" Spath.pp spath);
let data = EddsaPrivateKey.to_octets priv in
Bos.OS.File.write fpath data |> unwrap_msg
Fat.write fs spath data |> unwrap_msg
let write_key k = write_eddsa (key_fpath k) k.priv
let key_spath k =
let sfn_res = String.sub (EddsaPublicKey.to_b32 k.pub) 0 8 |> Sfn.of_string in
match sfn_res with
| Error _ -> failwith "not possible"
| Ok sfn -> Spath.(Cfg.key_dir / sfn)
let delete_file fpath =
(* check fpath just to be safe *)
let () =
let root = Fpath.v Cfg.key_dir in
if not @@ Fpath.is_rooted ~root fpath then
Fmt.failwith
"delete_file failure: file `%a` is not contained in secmod directory"
Fpath.pp fpath
in
Log.debug (fun m -> m "delete key file `%a`" Fpath.pp fpath);
let+ () = Bos.OS.File.delete ~must_exist:true fpath |> unwrap_msg in
let read_key fs spath =
Log.debug (fun m -> m "reading key file `%a`" Spath.pp spath);
let* data = Fat.read fs spath |> unwrap_msg in
(* todo: catch failure *)
let k = Bin.decode key_bin data (ref 0) in
Ok k
let write_key fs k =
let spath = key_spath k in
Log.debug (fun m -> m "writing key file `%a`" Spath.pp spath);
let data = Bin.to_string key_bin k in
Fat.write fs spath data |> unwrap_msg
let delete_file fs spath =
Log.debug (fun m -> m "delete key file `%a`" Spath.pp spath);
let+ () = Fat.remove fs spath |> unwrap_msg in
()
let get_key_dir_contents dir =
let* dir = Fpath.of_string dir |> unwrap_msg in
let* b = Bos.OS.Dir.create ~mode:0o700 dir |> unwrap_msg in
if b then Log.info (fun m -> m "created directory `%a`" Fpath.pp dir);
let+ l = Bos.OS.Dir.contents ~dotfiles:false ~rel:false dir |> unwrap_msg in
List.map Fpath.normalize l
(* -- *)
let gen_key t1 t2 =
let priv, pub = EddsaPrivateKey.generate () in
Log.debug (fun m ->
m "generated key (%a):@,`%s`" pp_filename (t1, t2)
(EddsaPublicKey.to_b32 pub));
{ priv; pub; t1; t2 }
let k = { priv; pub; t1; t2 } in
Log.debug (fun m -> m "generated key `%s`" (EddsaPublicKey.to_b32 pub));
k
let sort_keys l = List.sort (fun a b -> TimeAbsolute.compare a.t2 b.t2) l
@ -124,58 +121,50 @@ let gen_additional_keys_until_lookahead ~now l =
let new_keys = List.map (fun (t1, t2) -> gen_key t1 t2) periodes in
new_keys
let sm_key_fpath =
Result.get_ok
@@
let+ fpath = Fpath.of_string Cfg.sm_priv_key |> unwrap_msg in
Fpath.normalize fpath
(* we load sm_key separately
we don't accept non-key files in key_dir *)
let load_key fpath =
match parse_filename fpath with
| None -> Fmt.error "invalid file `%a`" Fpath.pp fpath
| Some (t1, t2) ->
let+ priv = read_key fpath in
let pub = EddsaPrivateKey.pub_of_priv priv in
{ priv; pub; t1; t2 }
let load () =
let* l = get_key_dir_contents Cfg.key_dir in
let l = List.filter (fun fpath -> not @@ Fpath.equal fpath sm_key_fpath) l in
let* keys = list_map load_key l in
let load fs =
let* () =
if Fat.exists fs Cfg.key_dir then Ok ()
else Fat.mkdir fs Cfg.key_dir |> unwrap_msg
in
let* l = Fat.ls fs Cfg.key_dir |> unwrap_msg in
let l = List.map (fun entry -> entry.Fat.name) l in
let l = List.map (Spath.add Cfg.key_dir) l in
let l =
List.filter (fun spath -> not @@ Spath.equal spath Cfg.sm_priv_key) l
in
let* keys = list_map (read_key fs) l in
match keys with
| [] -> Ok None
| _l ->
let* sm_key_priv = read_key sm_key_fpath in
let sm_pub = EddsaPrivateKey.pub_of_priv sm_key_priv in
let* sm_priv, sm_pub = read_eddsa fs Cfg.sm_priv_key in
let ht = Hashtbl.create 0xff in
let () = List.iter (fun k -> Hashtbl.replace ht k.pub k) keys in
Ok (Some { sm_key_priv; sm_pub; ht })
Ok (Some { fs; sm_priv; sm_pub; ht })
let init () =
let* opt = load () in
let init fs =
let* opt = load fs in
let* t =
match opt with
| Some t -> Ok t
| None ->
let sm_key_priv, sm_pub = EddsaPrivateKey.generate () in
let sm_priv, sm_pub = EddsaPrivateKey.generate () in
Log.debug (fun m ->
m "generated secmod key: `%s`" (EddsaPublicKey.to_b32 sm_pub));
let* () = write_eddsa sm_key_fpath sm_key_priv in
let ht = Hashtbl.create 0xff in
Ok { sm_key_priv; sm_pub; ht }
let t = { fs; sm_priv; sm_pub; ht } in
let* () = write_eddsa fs Cfg.sm_priv_key t.sm_priv in
Ok t
in
let now = TimeAbsolute.of_ptime (Ptime_clock.now ()) in
let now = TimeAbsolute.of_ptime (Mirage_ptime.now ()) in
let keys = List.of_seq @@ Hashtbl.to_seq_values t.ht in
let new_keys = gen_additional_keys_until_lookahead ~now keys in
List.iter (fun k -> Hashtbl.replace t.ht k.pub k) new_keys;
let+ () = list_iter write_key new_keys in
let+ () = list_iter (write_key fs) new_keys in
t
module Make () = struct
module Make (Fs : Fat.FS) = struct
let t =
match init () with
match init Fs.t with
| Error e -> Fmt.failwith "secmod_eddsa initialization failure: %s." e
| Ok t -> t
@ -185,13 +174,13 @@ module Make () = struct
let add t1 t2 =
let k = gen_key t1 t2 in
Hashtbl.replace t.ht k.pub k;
let+ () = write_key k in
let+ () = write_key t.fs k in
()
let delete pub =
let* k = find pub in
Hashtbl.remove t.ht k.pub;
delete_file (key_fpath k)
delete_file t.fs (key_spath k)
let _delete_outdated ~now =
Hashtbl.to_seq_values t.ht
@ -203,7 +192,7 @@ module Make () = struct
(* ---- *)
let sm_pub = t.sm_pub
let sign_secmod s = EddsaSignature.sign ~key:t.sm_key_priv s
let sign_secmod s = EddsaSignature.sign ~key:t.sm_priv s
let sign pub s =
let+ k = find pub in