[server] [client] [lib.scha] big update to review

This commit is contained in:
xdrm-brackets 2018-04-23 00:02:55 +02:00
parent 3c9964b0cb
commit 08581354a4
6 changed files with 249 additions and 32 deletions

View File

@ -66,22 +66,20 @@ func New(ctx *context.T, saveDir string) (*T, error) {
func (c *T) Send(w io.Writer) error {
/* (1) Generate the request */
var x1, x2 []byte
x1 := make([]byte, scha.HSIZE)
x2 := make([]byte, scha.HSIZE)
err := c.generateRequest(x1, x2)
if err != nil {
return err
}
if err != nil { return err }
/* (2) Write request into writer */
_, err = w.Write(x1)
if err != nil {
return err
}
_, err = w.Write(x2)
if err != nil {
return err
}
written, err := w.Write(x1)
if err != nil { return err }
if written != len(x1) { return errors.New("Cannot write x1") }
written, err = w.Write(x2)
if err != nil { return err }
if written != len(x1) { return errors.New("Cannot write x2") }
return nil
}
@ -100,8 +98,9 @@ func (c *T) Receive(r io.Reader) error {
errCode := make([]byte, 1)
read, err := r.Read(errCode)
if err != nil { return err }
if uint16(read) != 1 { return errors.New("Cannot read enough bytes") }
if uint16(read) != 1 { return errors.New("Cannot read error code") }
fmt.Printf("ERROR CODE : %d\n", errCode[0]);
/* (2) Manage success
---------------------------------------------------------*/
if errCode[0] == 0 {
@ -125,13 +124,13 @@ func (c *T) Receive(r io.Reader) error {
y1 := make([]byte, scha.HSIZE)
read, err = r.Read(y1)
if err != nil { return err }
if uint16(read) != scha.HSIZE { return errors.New("Cannot read enough bytes") }
if uint16(read) != scha.HSIZE { return errors.New("Cannot read y1") }
/* (2) Read y2 */
y2 := make([]byte, scha.HSIZE)
read, err = r.Read(y2)
if err != nil { return err }
if uint16(read) != scha.HSIZE { return errors.New("Cannot read enough bytes") }
if uint16(read) != scha.HSIZE { return errors.New("Cannot read enough y2") }
/* (3) Manage rescue mode */
err = c.rescue(y1, y2)
@ -140,3 +139,18 @@ func (c *T) Receive(r io.Reader) error {
return err
}
/* (5) TMP
*
---------------------------------------------------------*/
func (c *T) TMP() []byte {
hash, err := c.key.CurrentHash()
if err != nil { panic(err) }
c.key.Decrement()
return hash;
}

View File

@ -226,7 +226,7 @@ func (c *T) generateRequest(x1 []byte, x2 []byte) error {
---------------------------------------------------------*/
/* (1) Get current time id */
timeId, timeMod := timeid.Generate(c.ctx.Window())
fmt.Printf("Client.time[%d, %d]\n", timeId, timeMod);
/* (2) Convert time id to byte array */
timeIdBytes := make([]byte, 4)
binary.BigEndian.PutUint32(timeIdBytes, timeId)
@ -237,22 +237,20 @@ func (c *T) generateRequest(x1 []byte, x2 []byte) error {
/* (5) Calculate x1 and x2
---------------------------------------------------------*/
/* (1) Calculate x1 = h ^ h(timeId) */
x1 = xor.ByteArray(h0, hashedTimeId)
copy(x1, xor.ByteArray(h0, hashedTimeId))
if DEBUG {
fmt.Printf("\n=== x1 ===\n")
fmt.Printf(" hash is h0 = %x\n", h0)
fmt.Printf(" time id is n = %x[%d]\n", timeIdBytes, timeId)
fmt.Printf(" h(t) = %x\n", hashedTimeId)
fmt.Printf(" ---\n")
fmt.Printf(" x1 is h0+h(t) = %x\n", x1)
fmt.Printf(" ---\n")
fmt.Printf(" x1 is h0+h(t) = %X\n", x1)
fmt.Printf(" check x1+h(t) eq h0 = %x\n", xor.ByteArray(x1, hashedTimeId))
fmt.Printf(" check x1+h0 eq h(t) = %x\n", xor.ByteArray(x1, h0))
}
/* (2) Calculate x2 = h ^ h(timeId) ^ timeMod */
x2 = xor.ByteArray(h1, hashedTimeId)
copy(x2, xor.ByteArray(h1, hashedTimeId))
// only add time mod if code = 0
if c.key.MigrationCode() == 0 {
@ -264,10 +262,10 @@ func (c *T) generateRequest(x1 []byte, x2 []byte) error {
fmt.Printf(" next is h1 = %x\n", h1)
fmt.Printf(" time mod is m = %x[%d]\n", timeMod, timeMod)
fmt.Printf(" h(t) = %x\n", hashedTimeId)
fmt.Printf(" ---\n")
fmt.Printf(" x2 is h1+h(t)+m = %x\n", x2)
fmt.Printf(" ---\n")
fmt.Printf(" check x2+x1 %% 2 eq m = %d (%t)\n", uint8(xor.ByteArray(x1, x2)[0]%2), xor.ByteArray(x1, x2)[0]%2 == byte(timeMod))
if c.key.MigrationCode() == 0 { fmt.Printf(" x2 is h1+h(t)+m = %X\n", x2)
} else { fmt.Printf(" x2 is h1+h(t) = %X\n", x2) }
if c.key.MigrationCode() == 0 { fmt.Printf(" check x2+x1 %% 2 eq m = %d (%t)\n", uint8(xor.ByteArray(x1, x2)[0]%2), xor.ByteArray(x1, x2)[0]%2 == byte(timeMod))
} else { fmt.Printf(" check x2+x1 %% 2 eq m = %d (%t)\n", uint8(xor.ByteArray(x1, x2)[0]%2), xor.ByteArray(x1, x2)[0]%2 == byte(timeMod)) }
fmt.Printf(" check x2+x1 %% 3 eq o = %d (%t)\n", uint8(xor.ByteArray(x1, x2)[1]%3), uint8(xor.ByteArray(x1, x2)[1]%3) == c.key.MigrationCode())
}
@ -289,7 +287,7 @@ func (c *T) rescue(y1 []byte, y2 []byte) error {
/* (2) Try to guess time id from timeM */
timeId := timeid.Guess(c.ctx.Window(), timeMod)
var timeIdBytes []byte
timeIdBytes := make([]byte, 4)
binary.BigEndian.PutUint32(timeIdBytes, timeId)
/* (3) Hash timeId */

View File

@ -57,7 +57,7 @@ func Create(ctx *context.T) (*T, error) {
func (s T) CurrentHash() ([]byte, error) {
/* (1) Get digest */
digest, err := scha.Hash(s.sec, uint(s.depth))
digest, err := scha.Hash(s.sec, s.depth)
/* (2) Dispatch error */
if err != nil {

View File

@ -50,7 +50,7 @@ func hash(input []byte) []byte{
* @return err<error> If consistence error
*
---------------------------------------------------------*/
func Hash(input []byte, depth uint, options... []byte) ([]byte, error) {
func Hash(input []byte, depth uint16, options... []byte) ([]byte, error) {
/* (1) Manage errors errors

View File

@ -1,6 +1,7 @@
package server
import (
"git.xdrm.io/schastsp/lib/scha"
"io"
"os"
"path/filepath"
@ -57,6 +58,7 @@ func New(ctx *context.T, savePath string) (*T, error) {
inst.conf = absolutePath;
/* (5) Try to fetch hash from conf */
inst.hash = make([]byte, scha.HSIZE)
err = inst.fetch();
if err != nil { return nil, err }
@ -74,4 +76,63 @@ func New(ctx *context.T, savePath string) (*T, error) {
* @return err<error> Error or NIL if not
*
---------------------------------------------------------*/
func (s *T) HandleRequest(req io.Reader, res io.Writer) error { return nil }
func (s *T) HandleRequest(req io.Reader, res io.Writer) error {
/* (1) Manage request
---------------------------------------------------------*/
/* (1) Read x1 */
x1 := make([]byte, scha.HSIZE);
read, err := req.Read(x1);
if err != nil { return err }
if uint16(read) != scha.HSIZE { return errors.New("Cannot read enough bytes") }
/* (2) Read x2 */
x2 := make([]byte, scha.HSIZE);
read, err = req.Read(x2);
if err != nil { return err }
if uint16(read) != scha.HSIZE { return errors.New("Cannot read enough bytes") }
/* (3) Manage request */
errCode, err := s.manageRequest(x1, x2)
if err != nil { return err }
/* (4) Valid authentication */
if errCode == 0 {
response := []byte{0x00}
written, err := res.Write(response)
if written != 1 || err != nil { return err }
return nil;
}
/* (2) If not authenticated -> build resynchronisation response
---------------------------------------------------------*/
/* (1) Init y1 + y2 */
y1 := make([]byte, scha.HSIZE)
y2 := make([]byte, scha.HSIZE)
/* (2) Generate response */
err = s.generateResynchronisationResponse(y1, y2)
if err != nil { return err }
/* (3) Write error code */
responseCode := []byte{errCode}
written, err := res.Write(responseCode);
if err != nil { return err }
if written != len(responseCode) { return errors.New("Cannot write response code") }
/* (4) Write y1 into response */
written, err = res.Write(y1)
if err != nil { return err }
if written != len(y1) { return errors.New("Cannot write y1") }
/* (5) Write y2 into response */
written, err = res.Write(y2)
if err != nil { return err }
if written != len(y1) { return errors.New("Cannot write y2") }
return nil
}

View File

@ -1,6 +1,9 @@
package server
import (
"fmt"
"git.xdrm.io/schastsp/lib/timeid"
"git.xdrm.io/schastsp/lib/xor"
"git.xdrm.io/schastsp/lib/scha"
"encoding/binary"
"os"
@ -49,7 +52,7 @@ func (s *T) fetch() error {
/* (3) Try to fetch hash from file */
fetchedHash := make([]byte, scha.HSIZE)
err = binary.Read(file, binary.BigEndian, s.hash)
err = binary.Read(file, binary.BigEndian, fetchedHash)
if err != nil { return err }
/* (4) Fail if wrong size */
@ -58,7 +61,148 @@ func (s *T) fetch() error {
}
/* (5) Copy fetched hash into real one */
s.hash = fetchedHash
copy(s.hash, fetchedHash)
return nil
}
/* (3) Request management
*
* @x1<[]byte> First request component
* @x2<[]byte> Second request component
*
* @return code<byte> Error code
* 0 -> authenticated
* 1 -> request error -> may resynchronise
* 2 -> Unknown error (check in returned 'err')
* @return err<error> Error or NIL if not
*
---------------------------------------------------------*/
func (s *T) manageRequest(x1 []byte, x2 []byte) (byte, error) {
if DEBUG { fmt.Printf(" stored hash is H = %x\n", s.hash) }
/* (1) Extract meta data
---------------------------------------------------------*/
/* (1) Get xor between x1 and x2 */
x := xor.ByteArray(x1, x2)
/* (2) Extract migration code */
mcode := uint8(x[1]) % 3;
/* (3) Fail if no migration but different hashes */
if mcode == 0 && string(x1[2:]) != string(x2[2:]) {
return 1, nil
}
/* (2) TimeID management
---------------------------------------------------------*/
/* (1) Extract time mod */
timeMod := uint32(x[0]) % 2
/* (2) Try to guess time id */
timeId := timeid.Guess(s.ctx.Window(), timeMod)
timeIdBytes := make([]byte, 4)
fmt.Printf("Server.time[%d, %d]\n", timeId, timeMod);
binary.BigEndian.PutUint32(timeIdBytes, timeId)
/* (3) Hash guessed time id */
hashedTimeId, err := scha.Hash(timeIdBytes, 1);
if err != nil { return 2, err }
/* (3) Extract hashes
---------------------------------------------------------*/
/* (1) Extract hash from x0 */
h0 := xor.ByteArray(x1, hashedTimeId)
if DEBUG { fmt.Printf(" supposing hash is h0 = %x\n", h0) }
/* (2) Extract next hash from x1 */
h1 := xor.ByteArray(x2, hashedTimeId)
if DEBUG { fmt.Printf(" supposing next is h1 = %x\n", h1) }
/* (3) Only remove timeMod if migration code = 0 */
if mcode == 0 {
h1[0] = xor.Byte(h1[0], byte(timeMod))
}
/* (4) Hash h0 to compare with stored hash 's.hash'
---------------------------------------------------------*/
/* (1) Hash 1 time to check if matches */
hashedH0, err := scha.Hash(h0, 1)
if err != nil { return 2, err }
if DEBUG { fmt.Printf(" hashed is h(h0) = %x\n", hashedH0) }
/* (2) If migration code = 2 (Rescue mode) -> hash MIN times */
if mcode == 2 {
hashedH0, err = scha.Hash(h0, s.ctx.MinDepth())
if err != nil { return 2, err }
}
/* (3) Fail if does not match */
if string(hashedH0) != string(s.hash) {
return 1, nil
}
/* (5) Store next hash
---------------------------------------------------------*/
copy(s.hash, h1)
s.store();
return 0, nil
}
/* (4) Generate resynchronisation response
*
* @y1<[]byte> First response component to write into
* @y2<[]byte> Second response component to write into
*
* @return err<error> Error or nil if not
*
---------------------------------------------------------*/
func (s *T) generateResynchronisationResponse(y1 []byte, y2 []byte) error {
/* (1) Get current time id */
timeId, timeMod := timeid.Generate(s.ctx.Window())
/* (3) Hash the time id */
timeIdBytes := make([]byte, 4)
binary.BigEndian.PutUint32(timeIdBytes, timeId)
hashedTimeId, err := scha.Hash(timeIdBytes, 1);
if err != nil { return err }
/* (4) Process y1 = H ^ h(timeId) */
copy(y1, xor.ByteArray(s.hash, hashedTimeId))
/* (5) Process y2 = H ^ h(timeId) ^ timeMod = y1 ^ timeMod */
copy(y2, xor.ByteArray(s.hash, hashedTimeId))
y2[0] = xor.Byte(y2[0], byte(timeMod))
if DEBUG {
fmt.Printf("=== y1 ===\n")
fmt.Printf(" hash is H = %x\n", s.hash)
fmt.Printf(" time id is t = %x[%d]\n", timeId, timeId)
fmt.Printf(" h(t) = %x\n", hashedTimeId)
fmt.Printf(" y1 is H+h(t) = %x\n", y1)
fmt.Printf(" check y1+h(t) eq H = %x\n", xor.ByteArray(y1, hashedTimeId))
fmt.Printf(" check y1+H eq h(t) = %x\n", xor.ByteArray(y1, s.hash))
fmt.Printf("=== y2 ===\n")
fmt.Printf(" time mod is m = %x[%d]\n", timeMod, timeMod)
fmt.Printf(" y2 is y1+m = %x\n", y2)
}
return nil