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cryptsetup-generator: allow specifying options in /proc/cmdline 

The main usecase for this is to make it possible to use cryptsetup in
the initrd without it having to include a host-specific /etc/crypttab.

Tested-by: Thomas Bächler <thomas@archlinux.org>
This commit is contained in:
Tom Gundersen 2013-08-18 14:59:00 +08:00
parent 8c11d3c1b5
commit 7ab064a6d6
2 changed files with 98 additions and 4 deletions
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23
man/systemd-cryptsetup-generator.xml
View File

@ -137,6 +137,29 @@
will be activated in the initrd or the real root.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.options=</varname></term>
<term><varname>rd.luks.options=</varname></term>
<listitem><para>Takes a LUKS super
block UUID followed by an '=' and a string
of options separated by commas as argument.
This will override the options for the given
UUID.</para>
<para>If only a list of options, without an
UUID, is specified, they apply to any UUIDs not
specified elsewhere, and without an entry in
/etc/crypttab.</para><para>
<varname>rd.luks.options=</varname>
is honored only by initial RAM disk
(initrd) while
<varname>luks.options=</varname> is
honored by both the main system and
the initrd.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.key=</varname></term>
<term><varname>rd.luks.key=</varname></term>

79
src/cryptsetup/cryptsetup-generator.c
View File

@ -240,7 +240,7 @@ static int create_disk(
return 0;
}
static int parse_proc_cmdline(char ***arg_proc_cmdline_disks, char **arg_proc_cmdline_keyfile) {
static int parse_proc_cmdline(char ***arg_proc_cmdline_disks, char ***arg_proc_cmdline_options, char **arg_proc_cmdline_keyfile) {
_cleanup_free_ char *line = NULL;
char *w = NULL, *state = NULL;
int r;
@ -307,7 +307,20 @@ static int parse_proc_cmdline(char ***arg_proc_cmdline_disks, char **arg_proc_cm
return log_oom();
}
} else if (startswith(word, "luks.options=")) {
if (strv_extend(arg_proc_cmdline_options, word + 13) < 0)
return log_oom();
} else if (startswith(word, "rd.luks.options=")) {
if (in_initrd()) {
if (strv_extend(arg_proc_cmdline_options, word + 16) < 0)
return log_oom();
}
} else if (startswith(word, "luks.key=")) {
if (*arg_proc_cmdline_keyfile)
free(*arg_proc_cmdline_keyfile);
*arg_proc_cmdline_keyfile = strdup(word + 9);
if (!*arg_proc_cmdline_keyfile)
return log_oom();
@ -337,6 +350,7 @@ static int parse_proc_cmdline(char ***arg_proc_cmdline_disks, char **arg_proc_cm
int main(int argc, char *argv[]) {
_cleanup_strv_free_ char **arg_proc_cmdline_disks_done = NULL;
_cleanup_strv_free_ char **arg_proc_cmdline_disks = NULL;
_cleanup_strv_free_ char **arg_proc_cmdline_options = NULL;
_cleanup_free_ char *arg_proc_cmdline_keyfile = NULL;
_cleanup_fclose_ FILE *f = NULL;
unsigned n = 0;
@ -357,7 +371,7 @@ int main(int argc, char *argv[]) {
umask(0022);
if (parse_proc_cmdline(&arg_proc_cmdline_disks, &arg_proc_cmdline_keyfile) < 0)
if (parse_proc_cmdline(&arg_proc_cmdline_disks, &arg_proc_cmdline_options, &arg_proc_cmdline_keyfile) < 0)
return EXIT_FAILURE;
if (!arg_enabled)
@ -412,6 +426,26 @@ int main(int argc, char *argv[]) {
continue;
}
if (arg_proc_cmdline_options) {
/*
If options are specified on the kernel commandline, let them override
the ones from crypttab.
*/
STRV_FOREACH(i, arg_proc_cmdline_options) {
_cleanup_free_ char *proc_uuid = NULL, *proc_options = NULL;
const char *p = *i;
k = sscanf(p, "%m[0-9a-fA-F-]=%ms", &proc_uuid, &proc_options);
if (k == 2 && streq(proc_uuid, device + 5)) {
if (options)
free(options);
options = strdup(p);
if (!proc_options)
return log_oom();
}
}
}
if (arg_proc_cmdline_disks) {
/*
If luks UUIDs are specified on the kernel command line, use them as a filter
@ -452,7 +486,7 @@ next:
on the kernel command line and not yet written.
*/
_cleanup_free_ char *name = NULL, *device = NULL;
_cleanup_free_ char *name = NULL, *device = NULL, *options = NULL;
const char *p = *i;
if (startswith(p, "luks-"))
@ -467,7 +501,44 @@ next:
if (!name || !device)
return log_oom();
if (create_disk(name, device, arg_proc_cmdline_keyfile, "timeout=0") < 0)
if (arg_proc_cmdline_options) {
/*
If options are specified on the kernel commandline, use them.
*/
char **j;
STRV_FOREACH(j, arg_proc_cmdline_options) {
_cleanup_free_ char *proc_uuid = NULL, *proc_options = NULL;
const char *s = *j;
int k;
k = sscanf(s, "%m[0-9a-fA-F-]=%ms", &proc_uuid, &proc_options);
if (k == 2) {
if (streq(proc_uuid, device + 5)) {
if (options)
free(options);
options = strdup(proc_options);
if (!options)
return log_oom();
}
} else if (!options) {
/*
Fall back to options without a specified UUID
*/
options = strdup(s);
if (!options)
return log_oom();
}
}
}
if (!options) {
options = strdup("timeout=0");
if (!options)
return log_oom();
}
if (create_disk(name, device, arg_proc_cmdline_keyfile, options) < 0)
r = EXIT_FAILURE;
}