Source file checkct.ml
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open Types
open Ir
open Script
module S = Basic_types.String
module B = Bitvector.Collection
include Cli.Make (struct
let name = "Constant time checker"
let shortname = "checkct"
end)
type leak_info =
| HaltLeak (** Halts at first leak *)
| InstrLeak
(** Reports leaky instructions (each one is reported only once) *)
module LeakInfo = Builder.Variant_choice_assoc (struct
type t = leak_info
let name = "leak-info"
let doc =
"Select the information that is reported about leakage.\n"
^ "\t\t- halt: halts at first leak\n"
^ "\t\t- instr: reports leaky instructions (instructions are reported only \
once)\n"
let default = InstrLeak
let assoc_map = [ ("halt", HaltLeak); ("instr", InstrLeak) ]
end)
module Taint = Builder.No (struct
let name = "taint"
let doc = "Disable taint analysis (prove that instruction can not leak)"
end)
module ChosenValues = Builder.No (struct
let name = "cv"
let doc = "Disable chosen value sampling (prove that instruction may leak)"
end)
module Relse = Builder.No (struct
let name = "relse"
let doc = "Disable relational symbolic engine to answer security queries"
end)
module StatsFile = Builder.String_option (struct
let name = "stats-file"
let doc = "set file for dumping staistics"
end)
module Kind = struct
type t = Control_flow | Memory_access | Multiplication | Dividend | Divisor
let to_string = function
| Control_flow -> "control flow"
| Memory_access -> "memory access"
| Multiplication -> "multiplication"
| Dividend -> "dividend"
| Divisor -> "divisor"
let of_string = function
| "control-flow" -> Control_flow
| "memory-access" -> Memory_access
| "multiplication" -> Multiplication
| "dividend" -> Dividend
| "divisor" -> Divisor
| _ -> raise (Invalid_argument "of_string")
let pp ppf t = Format.pp_print_string ppf (to_string t)
end
module Features = Builder.Variant_list (struct
let name = "features"
let doc =
"Set of CT check points : control-flow, memory-access, multiplication, \
dividend and divisor. Multiplication and division checks are \
experimental."
let accept_empty = true
type t = Kind.t
let of_string = Kind.of_string
end)
module Report = struct
type t = {
memory : Bitvector.t B.Map.t S.Map.t;
public : Bitvector.t list S.Map.t;
secret1 : Bitvector.t list S.Map.t;
secret2 : Bitvector.t list S.Map.t;
}
let toml t =
let open Toml in
let toml_variable_vals m =
Min.of_key_values
(S.Map.fold
(fun name vals res ->
let toml_vals =
Types.NodeString (List.map Bitvector.to_string vals)
in
(Min.key name, Types.TArray toml_vals) :: res)
m [])
and toml_array_vals m =
Min.of_key_values
(B.Map.fold
(fun addr value res ->
( Min.key (Bitvector.to_string addr),
Types.TString (Bitvector.to_string value) )
:: res)
m [])
in
let toml_memory_vals m =
Min.of_key_values
(S.Map.fold
(fun name vals res ->
(Min.key name, Types.TTable (toml_array_vals vals)) :: res)
m [])
in
Min.of_key_values
[
(Min.key "memory", Types.TTable (toml_memory_vals t.memory));
(Min.key "public", Types.TTable (toml_variable_vals t.public));
(Min.key "secret1", Types.TTable (toml_variable_vals t.secret1));
(Min.key "secret2", Types.TTable (toml_variable_vals t.secret2));
]
let pp ppf t =
let pp_category ppf vars =
S.Map.iter
(fun name list ->
Format.fprintf ppf "@[<h> %s : @[<hov>%a@]@]@," name
(Format.pp_print_list ~pp_sep:Format.pp_print_space
Bitvector.pp_hex_or_bin)
list)
vars
and pp_array ppf array =
B.Map.iter
(fun addr value ->
Format.fprintf ppf "@[<h> %a : %a@]@," Bitvector.pp_hex_or_bin addr
Bitvector.pp_hex_or_bin value)
array
in
let pp_memory ppf memory =
S.Map.iter
(fun name values ->
Format.fprintf ppf "@[<v 1>%s :@,%a@]@," name pp_array values)
memory
in
Format.fprintf ppf
"@[<v 0>%a@[<v 1>public :@,\
%a@]@,\
@[<v 1>secret1 :@,\
%a@]@,\
@[<v 1>secret2 :@,\
%a@]@]"
pp_memory t.memory pp_category t.public pp_category t.secret1 pp_category
t.secret2
end
module Status = struct
type t = Secure | Insecure of Report.t | Unknown
let to_string = function
| Secure -> "secure"
| Insecure _ -> "insecure"
| Unknown -> "unknown"
let pp ppf t = Format.pp_print_string ppf (to_string t)
end
type Ast.Obj.t += Bool of bool
type Ast.Instr.t += Secret of Ast.Loc.t Ast.loc
type Ast.Instr.t += Se_check
type Ast.t += Globals of bool * string list
module type OPTIONS = sig
val leak_info : leak_info
val taint : bool
val cv : bool
val relse : bool
val stats_file : string option
val check_branch : bool
val check_memory : bool
val check_mult : bool
val check_dividend : bool
val check_divisor : bool
end
let make_options : unit -> (module OPTIONS) =
fun () : (module OPTIONS) ->
(module struct
let leak_info = LeakInfo.get ()
let taint = Taint.get ()
let cv = ChosenValues.get ()
let relse = Relse.get ()
let stats_file = StatsFile.get_opt ()
let features =
if Features.is_set () then Features.get ()
else [ Control_flow; Memory_access ]
let check_branch = List.memq Kind.Control_flow features
let check_memory = List.memq Kind.Memory_access features
let check_mult = List.memq Kind.Multiplication features
let check_dividend = List.memq Kind.Dividend features
let check_divisor = List.memq Kind.Divisor features
end)
let ( === ) = Sexpr.Expr.is_equal
let ( /== ) e e' = not (e === e')
module Ct_state = struct
open Sexpr
type load = ([ `Mem ], string, Memory.t) Term.t
type t = {
mutable constraints : Expr.t list;
mutable conjunction : Expr.t;
secrets : Expr.t BvTbl.t;
mirror_e : Expr.t BvTbl.t;
mirror_m : Memory.t AxTbl.t;
mutable loads : load list;
roots : Memory.t AxTbl.t;
mutable models : (int * Model.t) list;
}
let empty () =
let addr_space = Kernel_options.Machine.word_size () in
{
constraints = [];
conjunction = Expr.one;
secrets = BvTbl.create 8;
mirror_e = BvTbl.create 64;
mirror_m = AxTbl.create 16;
loads = [];
roots = AxTbl.create 16;
models = List.init 4 (fun i -> (i, Model.empty addr_space));
}
let fork t =
{
t with
mirror_e = BvTbl.copy t.mirror_e;
mirror_m = AxTbl.copy t.mirror_m;
secrets = BvTbl.copy t.secrets;
roots = AxTbl.copy t.roots;
}
let mirror (e : Expr.t) t =
match e with
| Var { name; size; label; _ } ->
let e' = Expr.var ("mirror_" ^ name) size label in
BvTbl.add t.mirror_e e e';
BvTbl.add t.secrets e' e
| _ -> raise_notrace (Invalid_argument "mirror")
let rec is_tainted (e : Expr.t) t =
try e /== BvTbl.find t.mirror_e e
with Not_found ->
(match e with
| Cst _ -> false
| Var _ -> false
| Load { label; _ } ->
t.loads <- Term.to_mem_exn e :: t.loads;
is_tainted_memory label t
| Unary { x; _ } -> is_tainted x t
| Binary { x; y; _ } -> is_tainted x t || is_tainted y t
| Ite { c; t = x; e = y; _ } ->
is_tainted c t || is_tainted x t || is_tainted y t)
||
(BvTbl.add t.mirror_e e e;
false)
and is_tainted_memory (m : Memory.t) t =
try not (Memory.equal m (AxTbl.find t.mirror_m m))
with Not_found -> (
match m with Root | Symbol _ -> false | Layer _ -> true)
let rec make_mirror_e (e : Expr.t) t =
try BvTbl.find t.mirror_e e
with Not_found ->
let e' =
match e with
| Cst _ -> e
| Var _ -> e
| Load { label; len; dir; addr; _ } ->
t.loads <- Term.to_mem_exn e :: t.loads;
let label' = make_mirror_m label t in
let addr' = make_mirror_e addr t in
if (not (Memory.equal label label')) || (addr /== addr') then
Expr.load len dir addr' label'
else e
| Unary { x; f; _ } ->
let x' = make_mirror_e x t in
if x /== x' then Expr._unary f x' else e
| Binary { x; y; f; _ } ->
let x' = make_mirror_e x t and y' = make_mirror_e y t in
if (x /== x') || (y /== y') then Expr._binary f x' y' else e
| Expr.Ite { c; t = x; e = y; _ } ->
let c' = make_mirror_e c t
and x' = make_mirror_e x t
and y' = make_mirror_e y t in
if (c /== c') || (x /== x') || (y /== y') then Expr._ite c' x' y'
else e
in
BvTbl.add t.mirror_e e e';
e'
and make_mirror_m (m : Memory.t) t =
try AxTbl.find t.mirror_m m
with Not_found ->
let m' =
match m with
| Root | Symbol _ ->
AxTbl.add t.roots m m;
m
| Layer { over; addr; store; _ } ->
let size = Expr.sizeof addr
and addr' = make_mirror_e addr t
and over' = make_mirror_m over t in
AxTbl.add t.roots m (AxTbl.find t.roots over);
let store', dirty =
Store.fold
(fun offset chunk (store', dirty) ->
let offset' = Bitvector.create offset size in
if Chunk.is_hunk chunk then
(Store.store offset' chunk store', dirty)
else
let value = Chunk.to_term chunk in
let value' = make_mirror_e value t in
( Store.store offset' (Chunk.of_term value') store',
dirty || (value /== value') ))
(Store.empty, false) store
in
if (addr /== addr') || dirty || not (Memory.equal over over') then
Memory.layer addr' store' over'
else m
in
AxTbl.add t.mirror_m m m';
m'
let make_context constraints t =
let rec visit constraints t conjunction =
if constraints == t.constraints then conjunction
else
match constraints with
| [] -> assert false
| e :: constraints ->
let e' = make_mirror_e e t in
visit constraints t
(if e /== e' then Expr.logand e' conjunction else conjunction)
in
t.conjunction <- visit constraints t t.conjunction;
t.constraints <- constraints
let rec find_root array t =
try AxTbl.find t.roots array
with Not_found ->
let root =
match array with
| Root | Symbol _ -> array
| Layer { over; _ } -> find_root over t
in
AxTbl.add t.roots array root;
root
end
module Make
(Options : OPTIONS)
(Stats : EXPLORATION_STATISTICS)
(Path : Path.S)
(State : STATE with type Value.t = Sexpr.Expr.t) :
Exec.EXTENSION with type path = Path.t and type state = State.t = struct
type path = Path.t
and state = State.t
let key = Path.register_key (Ct_state.empty ())
type builtin +=
| Mirror of Dba.Var.t
| Ct_check of Dba.Expr.t * Kind.t
| Se_check
let () =
Path.register_at_fork (fun path path' ->
Path.set key (Ct_state.fork (Path.get key path)) path')
module Eval = Eval.Make (Path) (State)
let ct_cf_secure = ref 0
and ct_cf_insecure = ref 0
and ct_cf_unknown = ref 0
and ct_mem_secure = ref 0
and ct_mem_insecure = ref 0
and ct_mem_unknown = ref 0
and ct_mult_secure = ref 0
and ct_mult_insecure = ref 0
and ct_mult_unknown = ref 0
and ct_div_secure = ref 0
and ct_div_insecure = ref 0
and ct_div_unknown = ref 0
let ct_status (kind : Kind.t) (status : Status.t) =
match (kind, status) with
| Control_flow, Secure -> ct_cf_secure
| Control_flow, Insecure _ -> ct_cf_insecure
| Control_flow, Unknown -> ct_cf_unknown
| Memory_access, Secure -> ct_mem_secure
| Memory_access, Insecure _ -> ct_mem_insecure
| Memory_access, Unknown -> ct_mem_unknown
| Multiplication, Secure -> ct_mult_secure
| Multiplication, Insecure _ -> ct_mult_insecure
| Multiplication, Unknown -> ct_mult_unknown
| (Dividend | Divisor), Secure -> ct_div_secure
| (Dividend | Divisor), Insecure _ -> ct_div_insecure
| (Dividend | Divisor), Unknown -> ct_div_unknown
let ct_addr_status : Status.t Virtual_address.Htbl.t =
Virtual_address.Htbl.create 128
let add_addr_status addr status =
Virtual_address.Htbl.replace ct_addr_status addr status
let is_addr_insecure addr =
match Virtual_address.Htbl.find ct_addr_status addr with
| Insecure _ -> true
| (exception Not_found) | Secure | Unknown -> false
let addr_status_report () =
let insecure, unknown =
Virtual_address.Htbl.fold
(fun addr (status : Status.t) (insecure, unknown) ->
match status with
| Insecure _ -> (addr :: insecure, unknown)
| Unknown -> (insecure, addr :: unknown)
| Secure -> assert false)
ct_addr_status ([], [])
in
( List.sort Virtual_address.compare insecure,
List.sort Virtual_address.compare unknown )
let toml_ct_report () =
let open Toml in
let l_insecure, l_unknown = addr_status_report () in
let ls_insecure, ls_unknown =
( List.map Virtual_address.to_string l_insecure,
List.map Virtual_address.to_string l_unknown )
in
let instructions_status =
Min.of_key_values
[
(Min.key "insecure", Types.TArray (Types.NodeString ls_insecure));
(Min.key "unknown", Types.TArray (Types.NodeString ls_unknown));
]
in
let insecurity_models =
Min.of_key_values
(Virtual_address.Htbl.fold
(fun vaddr (status : Status.t) l ->
match status with
| Insecure model ->
let toml_model = Report.toml model in
( Min.key (Virtual_address.to_string vaddr),
Types.TTable toml_model )
:: l
| Unknown -> l
| _ -> assert false)
ct_addr_status [])
in
Min.of_key_values
[
(Min.key "Instructions status", Types.TTable instructions_status);
(Min.key "Insecurity models", Types.TTable insecurity_models);
]
let is_unknown_report () =
Stats.get_pending_paths () > 0
|| !ct_cf_unknown + !ct_mem_unknown > 0
|| Stats.get_status Non_executable_code > 0
|| Stats.get_status Max_depth > 0
|| Stats.get_status Enumeration_limit > 0
|| Stats.get_status Unresolved_formula > 0
|| Stats.get_status Die > 0
let initialization_callback = None
let mirror var _ path _ state : (State.t, status) Result.t =
try
Ct_state.mirror (State.lookup var state) (Path.get key path);
Ok state
with Invalid_argument _ -> Error Die
let declaration_callback =
let lookup_symbol (env : env) name attr =
match env.lookup_symbol name attr with
| Var { info = Symbol (_, (lazy bv)); _ } -> bv
| _ -> assert false
in
Some
(fun decl env path state ->
match decl with
| Globals (secret, names) ->
Some
(List.fold_left
(fun state name ->
let addr = lookup_symbol env name Value
and bytesize =
Size.Byte.create
(Bitvector.to_uint (lookup_symbol env name Size))
in
let bitsize = Size.Byte.to_bitsize bytesize in
let var = Dba.Var.create name ~bitsize ~tag:Empty in
env.define var Lexing.dummy_pos;
let state = Eval.fresh var state path in
let value = State.lookup var state in
let state =
State.write
~addr:(State.Value.constant addr)
value LittleEndian state
in
if secret then
Result.get_ok
(mirror var Virtual_address.zero path 0 state)
else state)
state names)
| _ -> None)
let instruction_callback =
let secret = Printf.sprintf "%%secret%%%d" in
Some
(fun inst env ->
match inst with
| Secret lval -> (
match Script.eval_loc lval env with
| Var var -> [ Symbolize var; Builtin (Mirror var) ]
| Restrict (var, { hi; lo }) ->
let size' = hi - lo + 1 in
let name' = secret size' in
let var' = Dba.Var.temporary name' (Size.Bit.create size') in
let rval =
Dba_utils.Expr.complement (Dba.Expr.v var') ~lo ~hi var
in
[ Symbolize var'; Builtin (Mirror var'); Assign { var; rval } ]
| Store (bytes, dir, addr, base) ->
let size' = 8 * bytes in
let name' = secret size' in
let var' = Dba.Var.temporary name' (Size.Bit.create size') in
let rval = Dba.Expr.v var' in
[
Symbolize var';
Builtin (Mirror var');
Store { base; dir; addr; rval };
])
| Se_check -> [ Builtin Se_check ]
| _ -> [])
let process_handler : type a. (module Ir.GRAPH with type t = a) -> a -> unit =
fun graph ->
let module G = (val graph) in
let rec visit_expr graph vertex (e : Dba.Expr.t) =
match e with
| Cst _ | Var _ | Load _ -> ()
| Unary (_, x) -> visit_expr graph vertex x
| Binary (Mult, x, y) ->
if Options.check_mult then (
ignore
(G.insert_before graph vertex
(Builtin (Ct_check (x, Multiplication))));
ignore
(G.insert_before graph vertex
(Builtin (Ct_check (y, Multiplication)))));
visit_expr graph vertex x;
visit_expr graph vertex y
| Binary ((DivU | DivS | ModU | ModS), dividend, divisor) ->
if Options.check_dividend then
ignore
(G.insert_before graph vertex
(Builtin (Ct_check (dividend, Dividend))));
if Options.check_divisor then
ignore
(G.insert_before graph vertex
(Builtin (Ct_check (divisor, Divisor))));
visit_expr graph vertex dividend;
visit_expr graph vertex divisor
| Binary (_, x, y) ->
visit_expr graph vertex x;
visit_expr graph vertex y
| Ite (c, x, y) ->
visit_expr graph vertex c;
visit_expr graph vertex x;
visit_expr graph vertex y
in
fun graph ->
G.iter_new_vertex
(fun vertex ->
match G.node graph vertex with
| Fallthrough { kind = Load { addr; _ }; _ } ->
if Options.check_memory then
ignore
(G.insert_before graph vertex
(Builtin (Ct_check (addr, Memory_access))))
| Fallthrough { kind = Store { addr; rval; _ }; _ } ->
if Options.check_memory then
ignore
(G.insert_before graph vertex
(Builtin (Ct_check (addr, Memory_access))));
visit_expr graph vertex rval
| Fallthrough { kind = Assign { rval; _ }; _ } ->
visit_expr graph vertex rval
| Branch { test = expr; _ } | Terminator (Jump { target = expr; _ })
->
if Options.check_branch then
ignore
(G.insert_before graph vertex
(Builtin (Ct_check (expr, Control_flow))))
| _ -> ())
graph
let process_callback = Some process_handler
let taint_analysis e ct_state _ _ : Status.t =
if Ct_state.is_tainted e ct_state then Unknown else Secure
let cv_symbol (ct_state : Ct_state.t) (state : State.t) i e =
let open Sexpr in
if BvTbl.mem ct_state.secrets e then
match i with
| 0 -> Bv.zeros (Expr.sizeof e)
| 1 -> Bv.ones (Expr.sizeof e)
| 2 -> Bv.fill (Expr.sizeof e)
| _ -> Bv.rand (Expr.sizeof e)
else State.get_a_value e state
and cv_memory state array addr =
let open Sexpr in
Bv.to_char
(State.get_a_value
(Expr.load 1 LittleEndian (Expr.constant addr) array)
state)
let (ct_state : Ct_state.t) symbols state
((_, _, main, arrays, addr_size) as model) : Report.t =
let open Sexpr in
let memory =
StTbl.fold
(fun array bytes memory ->
S.Map.add array
(BiTbl.fold
(fun addr byte values ->
B.Map.add (Bv.create addr addr_size) (Bv.of_char byte) values)
bytes B.Map.empty)
memory)
arrays S.Map.empty
in
let memory =
if BiTbl.length main > 0 then
S.Map.add "@"
(BiTbl.fold
(fun addr byte values ->
B.Map.add (Bv.create addr addr_size) (Bv.of_char byte) values)
main B.Map.empty)
memory
else memory
in
let public, secret1, secret2 =
S.Map.fold
(fun name values (public, secret1, secret2) ->
let vpublic, vsecret1, vsecret2 =
List.fold_left
(fun (public, secret1, secret2) value ->
let value' =
try BvTbl.find ct_state.mirror_e value
with Not_found -> value
in
if value /== value' then
( public,
State.get_a_value value state :: secret1,
Model.eval model value' :: secret2 )
else (State.get_a_value value state :: public, secret1, secret2))
([], [], []) values
in
( (if vpublic <> [] then S.Map.add name vpublic public else public),
(if vsecret1 <> [] then S.Map.add name vsecret1 secret1 else secret1),
if vsecret2 <> [] then S.Map.add name vsecret2 secret2 else secret2
))
symbols
(S.Map.empty, S.Map.empty, S.Map.empty)
in
{ memory; public; secret1; secret2 }
let cv_analysis e (ct_state : Ct_state.t) symbols state : Status.t =
let open Sexpr in
match ct_state.models with
| [] -> Unknown
| models -> (
Ct_state.make_context (State.assertions state) ct_state;
let e' = Ct_state.make_mirror_e e ct_state in
if e === e' then Secure
else
let memory = cv_memory state in
ct_state.models <-
List.fold_left
(fun models (i, ((_, _, _, _, addr_space) as model)) ->
let symbols = cv_symbol ct_state state i in
let model =
if
List.exists
(fun e ->
Bv.is_zero (Model.eval ~symbols ~memory model e))
ct_state.constraints
then Model.empty addr_space
else model
in
if
Bv.is_one
(Model.eval ~symbols ~memory model ct_state.conjunction)
then (i, model) :: models
else models)
[] models;
let value = State.get_a_value e state in
match
List.find
(fun (i, model) ->
Bv.diff value
(Model.eval
~symbols:(cv_symbol ct_state state i)
~memory model e'))
ct_state.models
with
| exception Not_found -> Unknown
| _, model ->
Insecure (extract_cv_report ct_state symbols state model))
let (ct_state : Ct_state.t) symbols state : Report.t =
let open Sexpr in
let memory =
List.fold_left
(fun memory (Load { label; len; dir; addr; _ } : Ct_state.load) ->
let array = Ct_state.find_root label ct_state in
let name =
match array with
| Root -> "@"
| Symbol name -> name
| Layer _ -> assert false
in
let base = State.get_a_value addr state in
let bytes =
State.get_a_value
(Expr.load len dir (Expr.constant base) array)
state
in
let values =
try S.Map.find name memory with Not_found -> B.Map.empty
in
S.Map.add name (B.Map.add base bytes values) memory)
S.Map.empty ct_state.loads
in
let secret, public =
S.Map.partition
(fun _ values ->
let value = List.hd values in
try value /== BvTbl.find ct_state.mirror_e value
with Not_found -> false)
symbols
in
let public =
S.Map.map
(fun values ->
List.rev_map (fun value -> State.get_a_value value state) values)
public
and secret1 =
S.Map.map
(fun values ->
List.rev_map (fun value -> State.get_a_value value state) values)
secret
and secret2 =
S.Map.map
(fun values ->
List.rev_map
(fun value ->
State.get_a_value (BvTbl.find ct_state.mirror_e value) state)
values)
secret
in
{ memory; public; secret1; secret2 }
let relse_analysis e ct_state symbols state : Status.t =
let e' = Ct_state.make_mirror_e e ct_state in
if e === e' then Secure
else (
Ct_state.make_context (State.assertions state) ct_state;
match
State.assume Sexpr.Expr.(logand (diff e e') ct_state.conjunction) state
with
| exception Unknown -> Unknown
| None -> Secure
| Some state -> Insecure (extract_relse_report ct_state symbols state))
let analyses =
let analyses =
if Options.relse then [ ("RelSE", relse_analysis) ] else []
in
let analyses =
if Options.cv then ("chosen value", cv_analysis) :: analyses else analyses
in
let analyses =
if Options.taint then ("taint", taint_analysis) :: analyses else analyses
in
analyses
let analyze expr path state =
let rec apply_analyses e ct_state symbols state analyses : Status.t =
match analyses with
| [] -> Unknown
| (_, analysis) :: analyses ->
let status : Status.t = analysis e ct_state symbols state in
if status <> Unknown then status
else apply_analyses e ct_state symbols state analyses
in
apply_analyses expr (Path.get key path)
(Path.get State.symbols path)
state analyses
let ct_check expr (kind : Kind.t) addr path _ state :
(State.t, status) Result.t =
if Options.leak_info = InstrLeak && is_addr_insecure addr then Ok state
else
let expr, state = Eval.safe_eval expr state path in
let status : Status.t = analyze expr path state in
incr (ct_status kind status);
match status with
| Secure -> Ok state
| Insecure _ ->
add_addr_status addr status;
Logger.result "Instruction %a has %s leak (%.3fs)" Virtual_address.pp
addr (Kind.to_string kind) (Stats.get_time ());
if Options.leak_info = HaltLeak then Error Halt else Ok state
| Unknown ->
add_addr_status addr status;
Ok state
let se_check _ path _ state : (State.t, status) Result.t =
let addr =
State.Value.var (Path.get State.id path) "secret_seeker"
(Kernel_options.Machine.word_size ())
in
let read, state = State.read ~addr 1 LittleEndian state in
let symbols = Path.get State.symbols path in
Path.set State.symbols (S.Map.add "secret_seeker" [ addr ] symbols) path;
(match analyze read path state with
| Unknown -> Logger.warning "unknown status"
| Secure -> ()
| Insecure report -> Logger.error "%a" Report.pp report);
Path.set State.symbols symbols path;
Ok state
let builtin_callback =
Some
(function
| Mirror var -> Some (mirror var)
| Ct_check (expr, kind) -> Some (ct_check expr kind)
| Se_check -> Some se_check
| _ -> None)
let builtin_printer =
Some
(fun ppf -> function
| Mirror { name; _ } ->
Format.fprintf ppf "secret mirror(%s)" name;
true
| Ct_check (expr, kind) ->
Format.fprintf ppf "ct %a check(%a)" Kind.pp kind
Dba_printer.Ascii.pp_bl_term expr;
true
| Se_check ->
Format.pp_print_string ppf "secret-erasure check";
true
| _ -> false)
let at_exit_callback =
Some
(fun () ->
let l_insecure, _ = addr_status_report () in
let status =
if l_insecure <> [] then
Virtual_address.Htbl.find ct_addr_status (List.hd l_insecure)
else if is_unknown_report () then Unknown
else Secure
in
Option.iter
(fun filename ->
let toml_data =
Toml.Min.of_key_values
[
( Toml.Min.key "CT report",
Toml.Types.TTable (toml_ct_report ()) );
( Toml.Min.key "Exploration",
Toml.Types.TTable (Stats.to_toml ()) );
]
in
let oc = open_out_bin filename in
let ppf = Format.formatter_of_out_channel oc in
Toml.Printer.table ppf toml_data;
close_out oc)
Options.stats_file;
Logger.result "Program status is : %a (%0.3f)" Status.pp status
(Stats.get_time ());
if Options.leak_info = InstrLeak then (
let paths = Stats.get_completed_paths ()
and static_instrs = Stats.get_unique_insts () in
Logger.info "%d visited path%s covering %d instruction%s" paths
(if paths > 1 then "s" else "")
static_instrs
(if static_instrs > 1 then "s" else "");
if Options.check_branch then
Logger.info "%d / %d control flow checks pass" !ct_cf_secure
(!ct_cf_secure + !ct_cf_insecure + !ct_cf_unknown);
if Options.check_memory then
Logger.info "%d / %d memory access checks pass" !ct_mem_secure
(!ct_mem_secure + !ct_mem_insecure + !ct_mem_unknown);
if Options.check_mult then
Logger.info "%d / %d multiplication checks pass" !ct_mult_secure
(!ct_mult_secure + !ct_mult_insecure + !ct_mult_unknown);
if Options.check_dividend || Options.check_divisor then
Logger.info "%d / %d division checks pass" !ct_div_secure
(!ct_div_secure + !ct_div_insecure + !ct_div_unknown));
if is_unknown_report () then
Logger.warning "@[<v>Exploration is incomplete:%a@]"
(fun ppf () ->
let pendings = Stats.get_pending_paths () in
if pendings > 0 then
Format.fprintf ppf
"@ - timeout has left (at least) %d pending paths \
(-sse-timeout)"
pendings;
let non_exec = Stats.get_status Non_executable_code in
if non_exec > 0 then
Format.fprintf ppf
"@ - %d paths fell into non executable code segments" non_exec;
let max_depth = Stats.get_status Max_depth in
if max_depth > 0 then
Format.fprintf ppf
"@ - %d paths have reached the maximal depth and have been \
cut (-sse-depth)"
max_depth;
let incomplete_enum = Stats.get_status Enumeration_limit in
if incomplete_enum > 0 then
Format.fprintf ppf
"@ - some jump targets may have been omitted (-sse-jump-enum)";
let unknown =
Stats.get_status Unresolved_formula
+ !ct_cf_unknown + !ct_mem_unknown
in
if unknown > 0 then
Format.fprintf ppf
"@ - %d SMT solver queries remain unsolved \
(-fml-solver-timeout)"
unknown)
())
end
let () =
Exec.register_plugin
(module struct
let name = "checkct"
let grammar_extension =
[
Dyp.Bind_to_cons
[
("secret_or_public", "Obj");
("comma_separated_ident_rev_list", "Obj");
];
Dyp.Add_rules
[
( ( "secret_or_public",
[ Dyp.Regexp (RE_String "secret") ],
"default_priority",
[] ),
fun _ _ -> (Libparser.Syntax.Obj (Bool true), []) );
( ( "secret_or_public",
[ Dyp.Regexp (RE_String "public") ],
"default_priority",
[] ),
fun _ _ -> (Libparser.Syntax.Obj (Bool false), []) );
( ( "comma_separated_ident_rev_list",
[ Dyp.Non_ter ("ident", No_priority) ],
"default_priority",
[] ),
fun _ -> function
| [ Libparser.Syntax.String ident ] ->
(Libparser.Syntax.Obj (String_list [ ident ]), [])
| _ -> assert false );
( ( "comma_separated_ident_rev_list",
[
Dyp.Non_ter ("comma_separated_ident_rev_list", No_priority);
Dyp.Regexp (RE_Char ',');
Dyp.Non_ter ("ident", No_priority);
],
"default_priority",
[] ),
fun _ -> function
| [
Libparser.Syntax.Obj (String_list l);
_;
Libparser.Syntax.String ident;
] ->
(Libparser.Syntax.Obj (String_list (ident :: l)), [])
| _ -> assert false );
( ( "decl",
[
Dyp.Non_ter ("secret_or_public", No_priority);
Dyp.Regexp (RE_String "global");
Dyp.Non_ter ("comma_separated_ident_rev_list", No_priority);
],
"default_priority",
[] ),
fun _ -> function
| [
Libparser.Syntax.Obj (Bool secret);
_;
Libparser.Syntax.Obj (String_list names);
] ->
(Libparser.Syntax.(Decl (Globals (secret, names))), [])
| _ -> raise Dyp.Giveup );
( ( "decl",
[
Dyp.Regexp (RE_String "check");
Dyp.Regexp (RE_String "secret");
Dyp.Regexp (RE_String "erasure");
Dyp.Regexp (RE_String "over");
Dyp.Non_ter ("symbol", No_priority);
],
"default_priority",
[] ),
fun _ -> function
| [ _; _; _; _; Libparser.Syntax.Symbol symbol ] ->
( Libparser.Syntax.Decl
(Script.Return_hook
(symbol, [ Se_check; Script.Instr.halt ])),
[] )
| _ -> assert false );
( ( "fallthrough",
[
Dyp.Non_ter ("loc", No_priority);
Dyp.Regexp (RE_String ":=");
Dyp.Regexp (RE_String "secret");
],
"default_priority",
[] ),
fun _ -> function
| [ Libparser.Syntax.Loc lval; _; _ ] ->
(Libparser.Syntax.Instr (Secret lval), [])
| _ -> raise Dyp.Giveup );
( ( "fallthrough",
[
Dyp.Regexp (RE_String "check");
Dyp.Regexp (RE_String "secret");
Dyp.Regexp (RE_String "erasure");
],
"default_priority",
[] ),
fun _ -> function
| [ _; _; _ ] -> (Libparser.Syntax.Instr Se_check, [])
| _ -> raise Dyp.Giveup );
( ( "instr",
[
Dyp.Non_ter ("loc", No_priority);
Dyp.Regexp (RE_String ":=");
Dyp.Regexp (RE_String "secret");
Dyp.Non_ter ("accept_newline", No_priority);
Dyp.Ter "AS";
Dyp.Non_ter ("ident", No_priority);
],
"default_priority",
[] ),
fun _ -> function
| [
Libparser.Syntax.Loc lval;
_;
_;
_;
_;
Libparser.Syntax.String name;
] ->
let var =
( Ast.Loc.var name ~size:(Ast.Size.sizeof lval),
Lexing.dummy_pos )
in
( Libparser.Syntax.Stmt
[
Secret var;
Ast.Instr.assign lval
(Ast.Expr.loc var, Lexing.dummy_pos);
],
[] )
| _ -> assert false );
];
]
let instruction_printer =
Some
(fun ppf -> function
| Secret (loc, _) ->
Format.fprintf ppf "%a := secret" Ast.Loc.pp loc;
true
| Se_check ->
Format.fprintf ppf "check secret erasure";
true
| _ -> false)
let declaration_printer =
Some
(fun ppf -> function
| Globals (secret, names) ->
Format.fprintf ppf "%s global %a"
(if secret then "secret" else "public")
(Format.pp_print_list
~pp_sep:(fun ppf () -> Format.pp_print_string ppf ", ")
Format.pp_print_string)
names;
true
| _ -> false)
let extension :
type a b.
(module EXPLORATION_STATISTICS) ->
(module Path.S with type t = a) ->
(module STATE with type t = b) ->
(module Exec.EXTENSION with type path = a and type state = b) option =
fun stats path state ->
match is_enabled () with
| false -> None
| true -> (
let module State = (val state) in
match State.Value.kind with
| Senv.Term ->
if Options.Logger.is_debug_enabled () then
Logger.set_log_level "debug";
Logger.set_debug_level (Options.Logger.get_debug_level ());
Some
(module Make ((val make_options ())) ((val stats))
((val path))
(State))
| _ ->
Logger.fatal
"unable to use 'checkct' within the current symbolic engine")
end : Exec.PLUGIN)