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authorTom Gundersen <teg@jklm.no>2012-06-29 14:36:37 +0200
committerLennart Poettering <lennart@poettering.net>2012-07-09 22:07:52 +0200
commit880a599e262b9193219e612d827b35bb0c292dae (patch)
treecc98a4cdfec0b535afd79786b45cb64d7a7f91c2
parent2be7287b0eb88ec7ebc3117e59554c2f6e7ac9e4 (diff)
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cryptsetup: add keyfile-offset= support
This is useful if your keyfile is a block device, and you want to use a specific part of it, such as an area between the MBR and the first partition. This feature is documented in the Arch wiki[0], and has been supported by the Arch initscripts, so would be nice to get this into systemd. This requires libcryptsetup >= 1.4.2 (released 12.4.2012). Acked-by: Paul Menzel <paulepanter@users.sourceforge.net> [0]: <https://wiki.archlinux.org/index.php/System_Encryption_with_LUKS# Storing_the_key_between_MBR_and_1st_partition>
-rw-r--r--configure.ac2
-rw-r--r--man/crypttab.xml12
-rw-r--r--src/cryptsetup/cryptsetup.c11
3 files changed, 23 insertions, 2 deletions
diff --git a/configure.ac b/configure.ac
index bb60ecc166..c5fbec5738 100644
--- a/configure.ac
+++ b/configure.ac
@@ -333,7 +333,7 @@ AC_SUBST(AUDIT_LIBS)
have_libcryptsetup=no
AC_ARG_ENABLE(libcryptsetup, AS_HELP_STRING([--disable-libcryptsetup], [disable libcryptsetup tools]))
if test "x$enable_libcryptsetup" != "xno"; then
- PKG_CHECK_MODULES(LIBCRYPTSETUP, [ libcryptsetup ],
+ PKG_CHECK_MODULES(LIBCRYPTSETUP, [ libcryptsetup >= 1.4.2 ],
[AC_DEFINE(HAVE_LIBCRYPTSETUP, 1, [Define if libcryptsetup is available]) have_libcryptsetup=yes], have_libcryptsetup=no)
if test "x$have_libcryptsetup" = xno -a "x$enable_libcryptsetup" = xyes; then
AC_MSG_ERROR([*** libcryptsetup support requested but libraries not found])
diff --git a/man/crypttab.xml b/man/crypttab.xml
index f3bde71b4f..2fa8e8940f 100644
--- a/man/crypttab.xml
+++ b/man/crypttab.xml
@@ -131,6 +131,18 @@
<varlistentry>
+ <term><varname>keyfile-offset=</varname></term>
+
+ <listitem><para>Specifies the number
+ of bytes to skip at the start of
+ the keyfile; see
+ <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for possible values and the default
+ value of this option.</para></listitem>
+ </varlistentry>
+
+
+ <varlistentry>
<term><varname>hash=</varname></term>
<listitem><para>Specifies the hash to
diff --git a/src/cryptsetup/cryptsetup.c b/src/cryptsetup/cryptsetup.c
index b26fcca836..f570724b9d 100644
--- a/src/cryptsetup/cryptsetup.c
+++ b/src/cryptsetup/cryptsetup.c
@@ -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_offset = 0;
static char *opt_hash = NULL;
static unsigned opt_tries = 0;
static bool opt_readonly = false;
@@ -79,6 +80,13 @@ static int parse_one_option(const char *option) {
return 0;
}
+ } else if (startswith(option, "keyfile-offset=")) {
+
+ if (safe_atou(option+15, &opt_keyfile_offset) < 0) {
+ log_error("keyfile-offset= parse failure, ignoring.");
+ return 0;
+ }
+
} else if (startswith(option, "hash=")) {
char *t;
@@ -462,7 +470,8 @@ int main(int argc, char *argv[]) {
argv[3]);
if (key_file)
- k = crypt_activate_by_keyfile(cd, argv[2], CRYPT_ANY_SLOT, key_file, keyfile_size, flags);
+ k = crypt_activate_by_keyfile_offset(cd, argv[2], CRYPT_ANY_SLOT, key_file, keyfile_size,
+ opt_keyfile_offset, flags);
else {
char **p;