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// Author Taru Karttunen <taruti@taruti.net>
// This file can be used as both Public Domain or Creative Commons CC0.
#include <u.h>
#include <libc.h>
#include "crypt.h"
void format(char *file);
void copen(char *file);
char*readcons(char *prompt, char *def, int raw, char *buf, int nbuf);
int pkcs5_pbkdf2(const unsigned char *pass, int pass_len, const unsigned char *salt, int salt_len, unsigned char *key, int key_len, int rounds);
void
usage(void)
{
print("usage: \ncryptsetup -f deviceorfile \t\t\t\t\t# Format file or device\ncryptsetup -o deviceorfile >> /dev/fs/ctl \t# Open file or device\n");
exits("usage");
}
enum
{
NoMode,
Format,
Open,
};
void
main(int argc, char *argv[])
{
int mode;
char *file;
mode = 0;
ARGBEGIN {
default:
usage();
case 'f':
mode = Format;
break;
case 'o':
mode = Open;
break;
} ARGEND;
if((mode == NoMode) || (argc != 1))
usage();
file = argv[0];
switch(mode) {
case Format:
format(file);
break;
case Open:
copen(file);
break;
}
}
void
format(char *file)
{
char trand[48], pass1[64], pass2[64];
unsigned char tkey[16], tivec[16], buf[64*1024];
XtsState s;
AESstate cbc;
int i,j, fd;
do {
readcons("password", nil, 1, pass1, 64);
readcons("confirm", nil, 1, pass2, 64);
} while(strcmp(pass1, pass2) != 0);
do {
readcons("Are you sure you want to delete all data? (YES to procees)", nil, 0, (char*)buf, 4);
} while(strcmp((char*)buf, "YES") != 0);
srand(truerand());
for(i = 0; i < 16*4096; i++)
buf[i] = rand();
for(i = 0; i < 48; i+=4)
*((unsigned*)&trand[i]) = truerand();
memcpy(s.Master, trand, 32);
memcpy(s.Slots[0].Salt, trand+32, 16);
pkcs5_pbkdf2((unsigned char*)pass1, strlen(pass1), s.Slots[0].Salt, 16, (unsigned char*)tkey, 16, 9999);
memset(tivec, 0, 16);
setupAESstate(&cbc, tkey, 16, tivec);
memcpy(s.Slots[0].Key, s.Master, 32);
aesCBCencrypt(s.Slots[0].Key, 32, &cbc);
for(i=0; i<16; i++)
for(j=0; j<8; j++) {
buf[(4096*i)] = 1;
buf[(4096*i)+(4*j)+1] = s.Slots[j].Salt[i];
buf[(4096*i)+(4*j)+2] = s.Slots[j].Key[i];
buf[(4096*i)+(4*j)+3] = s.Slots[j].Key[i+16];
}
if((fd = open(file, OWRITE)) < 0)
exits("Cannot open disk");
/* make the pad for checking crypto */
for(i=0; i<8; i++) {
buf[(64*1024)-8+i] = ~buf[(64*1024)-16+i];
}
memset(tivec, 0, 16);
setupAESstate(&cbc, s.Master, 16, tivec);
aes_encrypt(cbc.ekey, cbc.rounds, &buf[(64*1024)-16], &buf[(64*1024)-16]);
write(fd, buf, 16*4096);
print("Disk written\n");
}
void copen(char *file) {
unsigned char pass[32], buf[1024*64], tkey[16], tivec[16];
XtsState s;
int i,j,fd;
AESstate cbc;
char *base, fdpath[1024];
if((fd = open(file, OREAD)) < 0)
exits("Cannot open disk");
if(read(fd, buf, 1024*64) != 1024*64)
exits("Cannot read disk");
for(i=0; i<16; i++)
for(j=0; j<8; j++) {
s.Slots[j].Salt[i] = buf[(4096*i)+(4*j)+1];
s.Slots[j].Key[i] = buf[(4096*i)+(4*j)+2];
s.Slots[j].Key[i+16] = buf[(4096*i)+(4*j)+3];
}
openpass:
readcons("Password", nil, 1, (char*)pass, 32);
memcpy(s.Master, s.Slots[0].Key, 32);
pkcs5_pbkdf2(pass, strlen((char*)pass), s.Slots[0].Salt, 16, tkey, 16, 9999);
memset(tivec, 0, 16);
setupAESstate(&cbc, tkey, 16, tivec);
aesCBCdecrypt(s.Master, 32, &cbc);
memset(tivec, 0, 16);
setupAESstate(&cbc, s.Master, 16, tivec);
aes_decrypt(cbc.dkey, cbc.rounds, &buf[(64*1024)-16], &buf[(64*1024)-16]);
/* make the pad for checking crypto */
for(i=0; i<8; i++)
if((buf[(64*1024)-8+i] ^ buf[(64*1024)-16+i]) != 255) {
goto openpass;
}
base = utfrrune(file, '/');
fd2path(fd, fdpath, 1024);
j = sprint((char*)buf, "crypt %s %s ", base ? base+1 : file, fdpath);
for(i=0; i<32; i++) {
sprint((char*)&buf[j], "%02X", s.Master[i]);
j += 2;
}
sprint((char*)&buf[j], "\n");
print("%s\n", (char*)buf);
}
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