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cryptsetup: add keyfile-size= support 

This is useful e.g. if the keyfile is a raw device, where only parts of it
should be read. It is typically used whenever the keyfile-offset= option is
specified.

Tested-by: Erik Westrup <erik.westrup@gmail.com>
This commit is contained in:
Tom Gundersen 2012-08-03 12:47:24 +02:00 committed by Lennart Poettering
parent f9a3b83bf4
commit 4271d8235f
2 changed files with 27 additions and 7 deletions
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12
man/crypttab.xml
View File

@ -130,6 +130,18 @@
</varlistentry>
<varlistentry>
<term><varname>keyfile-size=</varname></term>
<listitem><para>Specifies the maximum number
of bytes to read from the keyfile; see
<citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
for possible values and the default
value of this option. This option is ignored
in plain encryption mode, as the keyfile-size is then given by the key size.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>keyfile-offset=</varname></term>

22
src/cryptsetup/cryptsetup.c
View File

@ -37,6 +37,7 @@
static const char *opt_type = NULL; /* LUKS1 or PLAIN */
static char *opt_cipher = NULL;
static unsigned opt_key_size = 0;
static unsigned opt_keyfile_size = 0;
static unsigned opt_keyfile_offset = 0;
static char *opt_hash = NULL;
static unsigned opt_tries = 0;
@ -80,6 +81,13 @@ static int parse_one_option(const char *option) {
return 0;
}
} else if (startswith(option, "keyfile-size=")) {
if (safe_atou(option+13, &opt_keyfile_size) < 0) {
log_error("keyfile-size= parse failure, ignoring.");
return 0;
}
} else if (startswith(option, "keyfile-offset=")) {
if (safe_atou(option+15, &opt_keyfile_offset) < 0) {
@ -238,7 +246,6 @@ int main(int argc, char *argv[]) {
char **passwords = NULL, *truncated_cipher = NULL;
const char *cipher = NULL, *cipher_mode = NULL, *hash = NULL, *name = NULL;
char *description = NULL, *name_buffer = NULL, *mount_point = NULL;
unsigned keyfile_size = 0;
if (argc <= 1) {
help();
@ -437,6 +444,11 @@ int main(int argc, char *argv[]) {
zero(params);
params.hash = hash;
/* for CRYPT_PLAIN limit reads
* from keyfile to key length, and
* ignore keyfile-size */
opt_keyfile_size = opt_key_size / 8;
/* In contrast to what the name
* crypt_setup() might suggest this
* doesn't actually format anything,
@ -448,14 +460,10 @@ int main(int argc, char *argv[]) {
cipher_mode,
NULL,
NULL,
opt_key_size / 8,
opt_keyfile_size,
&params);
pass_volume_key = streq(hash, "plain");
/* for CRYPT_PLAIN limit reads
* from keyfile to key length */
keyfile_size = opt_key_size / 8;
}
if (k < 0) {
@ -470,7 +478,7 @@ int main(int argc, char *argv[]) {
argv[3]);
if (key_file)
k = crypt_activate_by_keyfile_offset(cd, argv[2], CRYPT_ANY_SLOT, key_file, keyfile_size,
k = crypt_activate_by_keyfile_offset(cd, argv[2], CRYPT_ANY_SLOT, key_file, opt_keyfile_size,
opt_keyfile_offset, flags);
else {
char **p;