common.ml

open Printf

type reg = EAX | EBX | ECX | EDX | ESI | EDI | EBP | ESP
type op = ADD | SUB | MUL | DIV | XOR | OR | AND
type gadget =  
            | LoadConst of reg * int (* reg, stack offset *)
            | CopyReg of reg * reg (* dst reg = src reg *)
            | BinOp of reg * reg * op * reg (* dst reg = src1 OP src2 *)
            | ReadMem of reg * reg * int32 (* dst = [addr_reg + offset] *)
            | WriteMem of reg * int32 * reg (* [addr_reg + offset] = src *)
            | ReadMemOp of reg * op * reg * int32 (* dst OP= [addr_reg + offset] *)
            | WriteMemOp of reg * int32 * op * reg (* [addr_reg + offset] OP= src_reg *)
            | Lahf 
            | OpEsp of op * reg * int (* esp = esp op reg, where op=+/-, sf =
                stack_fix *)

(* (offset_start, offset_end) *)
type fmeta = FileMeta of int * int
(* gadget, file meta, modified registers, stack_fix *)
type gmeta = GMeta of gadget * fmeta * reg list * int 
(* filename, (data section start, data section end), gadget list 
    type used for marshaling candidates for verification *)
type gcontainer = GContainer of string * (int * int) * gmeta list

let rEGS = [EAX; EBX; ECX; EDX; ESI; EDI; EBP; ESP;] 
let rEGS_NO_ESP = [EAX; EBX; ECX; EDX; ESI; EDI; EBP;] 

let dump_reg r = 
    match r with
    | EAX -> "eax"
    | EBX -> "ebx"
    | ECX -> "ecx"
    | EDX -> "edx"
    | ESI -> "esi"
    | EDI -> "edi"
    | EBP -> "ebp"
    | ESP -> "esp"

let dump_op op =
    match op with
    | ADD -> "+"
    | SUB -> "-"
    | MUL -> "*"
    | DIV -> "/"
    | XOR -> "^"
    | AND -> "&"
    | OR  -> "|"

let dump_filemeta fm = 
    let FileMeta(off_s, off_e) = fm in
    let s = sprintf "(s: 0x%x, e: 0x%x)" off_s off_e in
    s


let dump_gadget g = 
    match g with
    | LoadConst(r, off) -> sprintf "LoadConst(%s, 0x%x)" (dump_reg r) off
    | CopyReg(r1, r2) -> sprintf "CopyReg(%s, %s)" (dump_reg r1) (dump_reg r2)
    | BinOp(r_dst,r1,op,r2) -> sprintf "BinOp(%s, %s, %s, %s)" (dump_reg r_dst) (dump_reg r1) (dump_op op) (dump_reg r2)
    | ReadMem(r_dst, r_addr, off) -> sprintf "ReadMem(%s = [%s+0x%lx])" (dump_reg r_dst) (dump_reg r_addr) off
    | WriteMem(r_addr, off, r_src) -> sprintf "WriteMem([%s+0x%lx] = %s)" (dump_reg r_addr) off (dump_reg r_src)
    | ReadMemOp(r_dst, op, r_addr, off) -> sprintf "ReadMemOp(%s %s= [%s+0x%lx])" (dump_reg r_dst) (dump_op op) (dump_reg r_addr) off 
    | WriteMemOp(r_addr, off, op, r_src) -> sprintf "WriteMemOp([%s+0x%lx] %s= %s)" (dump_reg r_addr) off (dump_op op) (dump_reg r_src)
    | OpEsp(op, r, sf) -> sprintf "OpEsp(%s, %s, %d)" (dump_op op) (dump_reg r) sf
    | Lahf -> "Lahf"


let uniq eq l = 
    let rec aux l last uni dupes =
        match l with
        | hd::tl ->
            if eq hd last = 0 then
                aux tl last uni (hd::dupes)
            else
                aux tl hd (hd::uni) dupes
        | [] -> uni, dupes
    in
    match l with
    | [] -> l,l
    | hd::[] -> l, []
    | hd::tl -> aux tl hd [hd] []


let unique eq l = 
    let u, _ = uniq eq l in
    u

let nonunique eq l = 
    let _, nu = uniq eq l in
    nu

let generic_unique l = 
    let l = List.sort compare l in
    unique compare l

let create_hashtable size init =
    let tbl = Hashtbl.create size in
    List.iter (fun (key, data) -> Hashtbl.add tbl key data) init;
    tbl

let file_exc filename e = 
    Format.printf "Cannot open file \"%s\": %s\n" filename (Printexc.to_string e);
    assert false

let open_file fn fopen = 
    try
        let co = fopen fn in
        co
    with Sys_error _ as e ->
        file_exc fn e

let open_file_in fn = open_file fn open_in_bin
let open_file_out fn = open_file fn open_out_bin

let write_str_to_file filename str = 
    let co = open_file_out filename in
    (* let co = Format.formatter_of_out_channel co in*)
    output_string co str;
    close_out co

let read_file fn =
    let ic = open_file_in fn in
    let n = in_channel_length ic in
    let s = String.create n in
    really_input ic s 0 n;
    close_in ic;
    (s)

let marshal_to_file fn thing = 
    let co = open_file_out fn in
    Marshal.to_channel co thing [] 

let unmarshal_from_file fn = 
    let ic = open_file_in fn in
    let obj = Marshal.from_channel ic in
    obj

(* this assumes that RET is the last instruction *)
let drop_last stmts =     
    let stmts = List.rev (List.tl (List.rev stmts)) in
    stmts

let find_all p l = 
    let f acc x = if p x then (x::acc) else acc in
    List.fold_left f [] l 

let generic_dumper f_dump l =
    let f _ x = Printf.printf "%s;" (f_dump x) in
    let _ = List.fold_left f () l in
    ()        

let dump_int_list l = 
    let f acc x =  
        let s = string_of_int x in
        acc^";"^s
    in
    List.fold_left f "" l

let get_gadgets gmetas = 
    let strip acc gm = 
        let GMeta(g,_,_,_) = gm in
        g::acc
    in
    let gadgets = List.fold_left strip [] gmetas in
    gadgets