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// Original 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 <libsec.h>
#include <authsrv.h>
typedef struct {
uchar Salt[16];
uchar Key[32];
} Slot;
typedef struct {
uchar Master[32];
Slot Slots[8];
AESstate C1, C2;
} XtsState;
uchar zeros[16] = {0};
uchar buf[64*1024];
AESstate cbc;
XtsState s;
void
setupkey(char *pass, uchar salt[16], AESstate *aes)
{
uchar tkey[32];
pbkdf2_x((uchar*)pass, strlen(pass), salt, 16, 9999, tkey, 32, hmac_sha1, SHA1dlen);
setupAESstate(aes, tkey, 16, zeros);
memset(tkey, 0, sizeof(tkey));
}
void
freepass(char *pass)
{
if(pass != nil){
memset(pass, 0, strlen(pass));
free(pass);
}
}
void
cformat(char *files[])
{
char *pass, *tmp;
int fd, i, j;
pass = nil;
do {
freepass(pass);
pass = readcons("Password", nil, 1);
if(pass == nil || pass[0] == 0)
sysfatal("input aborted");
tmp = readcons("Confirm", nil, 1);
if(tmp == nil || tmp[0] == 0)
sysfatal("input aborted");
i = strcmp(pass, tmp);
freepass(tmp);
} while(i != 0);
for(;*files != nil; files++) {
genrandom((uchar*)&s, sizeof(s));
setupkey(pass, s.Slots[0].Salt, &cbc);
memcpy(s.Slots[0].Key, s.Master, 32);
aesCBCencrypt(s.Slots[0].Key, 32, &cbc);
genrandom(buf, 16*4096);
for(i=0; i<16; i++)
for(j=0; j<8; j++) {
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(*files, OWRITE)) < 0)
sysfatal("open disk: %r");
/* make the pad for checking crypto */
for(i=0; i<8; i++)
buf[(64*1024)-8+i] = ~buf[(64*1024)-16+i];
setupAESstate(&cbc, s.Master, 16, zeros);
aes_encrypt(cbc.ekey, cbc.rounds, &buf[(64*1024)-16], &buf[(64*1024)-16]);
if(write(fd, buf, 64*1024) != 64*1024)
sysfatal("writing disk: %r");
}
}
void
copen(char *files[], int ctl)
{
char *pass, *name;
uchar cbuf[16];
int fd, i, j;
pass = nil;
for(;*files != nil; files++) {
memset(&s, 0, sizeof(s));
if((fd = open(*files, OREAD)) < 0)
sysfatal("open disk: %r");
if(read(fd, buf, 1024*64) != 1024*64)
sysfatal("read disk: %r");
retrypass:
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];
}
if(pass == nil){
pass = readcons("Password", nil, 1);
if(pass == nil || pass[0] == 0)
sysfatal("input aborted");
}
setupkey(pass, s.Slots[0].Salt, &cbc);
memcpy(s.Master, s.Slots[0].Key, 32);
aesCBCdecrypt(s.Master, 32, &cbc);
setupAESstate(&cbc, s.Master, 16, zeros);
memcpy(cbuf, &buf[(64*1024)-16], 16);
aes_decrypt(cbc.dkey, cbc.rounds, cbuf, cbuf);
/* make the pad for checking crypto */
for(i=0; i<8; i++)
if((cbuf[i] ^ cbuf[i+8]) != 255) {
freepass(pass);
pass = nil;
fprint(2, "wrong key\n");
goto retrypass;
}
fd2path(fd, (char*)buf, sizeof(buf));
close(fd);
if((name = strrchr(*files, '/')) != nil)
name++;
else
name = *files;
if(fprint(ctl, "crypt %q %q %.32H\n", name, (char*)buf, s.Master) < 0)
sysfatal("write: %r");
}
}
void
usage(void)
{
print("usage:\n"
"%s -f files\t\t# Format file or device\n"
"%s -o files\t\t# Print commandline for open\n"
"%s -i files\t\t# Install (open) files\n",
argv0, argv0, argv0);
exits("usage");
}
void
main(int argc, char *argv[])
{
enum {
NoMode,
Format,
Open,
Install,
};
int mode, ctl;
quotefmtinstall();
fmtinstall('H', encodefmt);
ctl = 1;
mode = NoMode;
ARGBEGIN {
default:
usage();
case 'f':
mode = Format;
break;
case 'o':
mode = Open;
break;
case 'i':
mode = Install;
break;
} ARGEND;
if(argc < 0)
usage();
switch(mode){
default:
usage();
case Format:
cformat(argv);
break;
case Install:
if((ctl = open("/dev/fs/ctl", OWRITE)) < 0)
sysfatal("open ctl: %r");
/* no break */
case Open:
copen(argv, ctl);
break;
}
exits(nil);
}
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