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Teach gbde(8) to use a key file in addition to a passphrase. This

Browse Source 
makes it practical to use GBDE for "something you have plus something
you know" security together with a USB flash drive.

Reviewed by:	phk
MFC after:	7 days
This commit is contained in:
Colin Percival 2006-02-08 06:52:15 +00:00
parent c68a0f14fd
commit 6d118bffe7
2 changed files with 85 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
sbin/gbde/gbde.8
View File

@ -41,6 +41,7 @@
.Nm
.Cm attach
.Ar destination
.Op Fl k Ar keyfile
.Op Fl l Ar lockfile
.Op Fl p Ar pass-phrase
.Nm
@ -51,25 +52,30 @@
.Ar destination
.Op Fl i
.Op Fl f Ar filename
.Op Fl K Ar new-keyfile
.Op Fl L Ar new-lockfile
.Op Fl P Ar new-pass-phrase
.Nm
.Cm setkey
.Ar destination
.Op Fl n Ar key
.Op Fl k Ar keyfile
.Op Fl l Ar lockfile
.Op Fl p Ar pass-phrase
.Op Fl K Ar new-keyfile
.Op Fl L Ar new-lockfile
.Op Fl P Ar new-pass-phrase
.Nm
.Cm nuke
.Ar destination
.Op Fl n Ar key
.Op Fl k Ar keyfile
.Op Fl l Ar lockfile
.Op Fl p Ar pass-phrase
.Nm
.Cm destroy
.Ar destination
.Op Fl k Ar keyfile
.Op Fl l Ar lockfile
.Op Fl p Ar pass-phrase
.Sh DESCRIPTION
@ -180,6 +186,24 @@ Be aware that using this option may expose the pass-phrase to other
users who happen to run
.Xr ps 1
or similar while the command is running.
.Pp
The
.Fl k Ar keyfile
argument specifies a key file to be used in combination with the
pass-phrase (whether the pass-phrase is specified on the command line
or entered from the terminal) for opening the device.
The device will only be opened if the contents of the key file and the
pass-phrase are both correct.
.Pp
The
.Fl K Ar new-keyfile
argument can be used to specify a new key file to the
.Cm init
and
.Cm setkey
subcommands.
If not specified, no key file will be used (even if one was previously
used).
.Sh EXAMPLES
To initialize a device, using default parameters:
.Pp

86
sbin/gbde/gbde.c
View File

@ -134,14 +134,16 @@ usage(void)
{
(void)fprintf(stderr,
"usage: gbde attach destination [-l lockfile] [-p pass-phrase]\n"
"usage: gbde attach destination [-k keyfile] [-l lockfile] [-p pass-phrase]\n"
" gbde detach destination\n"
" gbde init destination [-i] [-f filename] [-L new-lockfile]\n"
" [-P new-pass-phrase]\n"
" gbde setkey destination [-n key] [-l lockfile] [-p pass-phrase]\n"
" gbde init destination [-i] [-f filename] [-K new-keyfile]\n"
" [-L new-lockfile] [-P new-pass-phrase]\n"
" gbde nuke destination [-n key] [-l lockfile] [-p pass-phrase]\n"
" gbde destroy destination [-l lockfile] [-p pass-phrase]\n");
" gbde setkey destination [-n key]\n"
" [-k keyfile] [-l lockfile] [-p pass-phrase]\n"
" [-K new-keyfile] [-L new-lockfile] [-P new-pass-phrase]\n"
" gbde nuke destination [-n key]\n"
" [-k keyfile] [-l lockfile] [-p pass-phrase]\n"
" gbde destroy destination [-k keyfile] [-l lockfile] [-p pass-phrase]\n");
exit(1);
}
@ -195,42 +197,67 @@ reset_passphrase(struct g_bde_softc *sc)
}
static void
setup_passphrase(struct g_bde_softc *sc, int sure, const char *input)
setup_passphrase(struct g_bde_softc *sc, int sure, const char *input,
const char *keyfile)
{
char buf1[BUFSIZ], buf2[BUFSIZ], *p;
char buf1[BUFSIZ + SHA512_DIGEST_LENGTH];
char buf2[BUFSIZ + SHA512_DIGEST_LENGTH];
char *p;
int kfd, klen, bpos = 0;
if (keyfile != NULL) {
/* Read up to BUFSIZ bytes from keyfile */
kfd = open(keyfile, O_RDONLY, 0);
if (kfd < 0)
err(1, "%s", keyfile);
klen = read(kfd, buf1, BUFSIZ);
if (klen == -1)
err(1, "%s", keyfile);
close(kfd);
/* Prepend the passphrase with the hash of the key read */
g_bde_hash_pass(sc, buf1, klen);
memcpy(buf1, sc->sha2, SHA512_DIGEST_LENGTH);
memcpy(buf2, sc->sha2, SHA512_DIGEST_LENGTH);
bpos = SHA512_DIGEST_LENGTH;
}
if (input != NULL) {
g_bde_hash_pass(sc, input, strlen(input));
if (strlen(input) >= BUFSIZ)
errx(1, "Passphrase too long");
strcpy(buf1 + bpos, input);
g_bde_hash_pass(sc, buf1, strlen(buf1 + bpos) + bpos);
memcpy(sha2, sc->sha2, SHA512_DIGEST_LENGTH);
return;
}
for (;;) {
p = readpassphrase(
sure ? "Enter new passphrase:" : "Enter passphrase: ",
buf1, sizeof buf1,
buf1 + bpos, sizeof buf1 - bpos,
RPP_ECHO_OFF | RPP_REQUIRE_TTY);
if (p == NULL)
err(1, "readpassphrase");
if (sure) {
p = readpassphrase("Reenter new passphrase: ",
buf2, sizeof buf2,
buf2 + bpos, sizeof buf2 - bpos,
RPP_ECHO_OFF | RPP_REQUIRE_TTY);
if (p == NULL)
err(1, "readpassphrase");
if (strcmp(buf1, buf2)) {
if (strcmp(buf1 + bpos, buf2 + bpos)) {
printf("They didn't match.\n");
continue;
}
}
if (strlen(buf1) < 3) {
if (strlen(buf1 + bpos) < 3) {
printf("Too short passphrase.\n");
continue;
}
break;
}
g_bde_hash_pass(sc, buf1, strlen(buf1));
g_bde_hash_pass(sc, buf1, strlen(buf1 + bpos) + bpos);
memcpy(sha2, sc->sha2, SHA512_DIGEST_LENGTH);
}
@ -708,6 +735,7 @@ int
main(int argc, char **argv)
{
const char *opts;
const char *k_opt, *K_opt;
const char *l_opt, *L_opt;
const char *p_opt, *P_opt;
const char *f_opt;
@ -730,26 +758,26 @@ main(int argc, char **argv)
doopen = 0;
if (!strcmp(argv[1], "attach")) {
action = ACT_ATTACH;
opts = "l:p:";
opts = "k:l:p:";
} else if (!strcmp(argv[1], "detach")) {
action = ACT_DETACH;
opts = "";
} else if (!strcmp(argv[1], "init")) {
action = ACT_INIT;
doopen = 1;
opts = "f:iL:P:";
opts = "f:iK:L:P:";
} else if (!strcmp(argv[1], "setkey")) {
action = ACT_SETKEY;
doopen = 1;
opts = "l:L:n:p:P:";
opts = "k:K:l:L:n:p:P:";
} else if (!strcmp(argv[1], "destroy")) {
action = ACT_DESTROY;
doopen = 1;
opts = "l:p:";
opts = "k:l:p:";
} else if (!strcmp(argv[1], "nuke")) {
action = ACT_NUKE;
doopen = 1;
opts = "l:n:p:";
opts = "k:l:n:p:";
} else {
usage();
}
@ -762,6 +790,8 @@ main(int argc, char **argv)
p_opt = NULL;
P_opt = NULL;
k_opt = NULL;
K_opt = NULL;
l_opt = NULL;
L_opt = NULL;
f_opt = NULL;
@ -775,6 +805,12 @@ main(int argc, char **argv)
break;
case 'i':
i_opt = !i_opt;
case 'k':
k_opt = optarg;
break;
case 'K':
K_opt = optarg;
break;
case 'l':
l_opt = optarg;
break;
@ -819,7 +855,7 @@ main(int argc, char **argv)
gl = &sc.key;
switch(action) {
case ACT_ATTACH:
setup_passphrase(&sc, 0, p_opt);
setup_passphrase(&sc, 0, p_opt, k_opt);
cmd_attach(&sc, dest, l_opt);
break;
case ACT_DETACH:
@ -827,26 +863,26 @@ main(int argc, char **argv)
break;
case ACT_INIT:
cmd_init(gl, dfd, f_opt, i_opt, L_opt);
setup_passphrase(&sc, 1, P_opt);
setup_passphrase(&sc, 1, P_opt, K_opt);
cmd_write(gl, &sc, dfd, 0, L_opt);
break;
case ACT_SETKEY:
setup_passphrase(&sc, 0, p_opt);
setup_passphrase(&sc, 0, p_opt, k_opt);
cmd_open(&sc, dfd, l_opt, &nkey);
if (n_opt == 0)
n_opt = nkey + 1;
setup_passphrase(&sc, 1, P_opt);
setup_passphrase(&sc, 1, P_opt, K_opt);
cmd_write(gl, &sc, dfd, n_opt - 1, L_opt);
break;
case ACT_DESTROY:
setup_passphrase(&sc, 0, p_opt);
setup_passphrase(&sc, 0, p_opt, k_opt);
cmd_open(&sc, dfd, l_opt, &nkey);
cmd_destroy(gl, nkey);
reset_passphrase(&sc);
cmd_write(gl, &sc, dfd, nkey, l_opt);
break;
case ACT_NUKE:
setup_passphrase(&sc, 0, p_opt);
setup_passphrase(&sc, 0, p_opt, k_opt);
cmd_open(&sc, dfd, l_opt, &nkey);
if (n_opt == 0)
n_opt = nkey + 1;