[arch-projects] [mkinitcpio] systemd in initramfs

Tom Gundersen teg at jklm.no
Sun Aug 18 04:47:55 EDT 2013


On Sun, Aug 18, 2013 at 8:48 AM, Tom Gundersen <teg at jklm.no> wrote:
> Hi Thomas,
>
> Thanks for your work on all this, I was hoping someone would pick this up.
>
> On Sun, Aug 18, 2013 at 12:45 AM, Thomas Bächler <thomas at archlinux.org> wrote:
>> Am 17.08.2013 17:08, schrieb Thomas Bächler:
>>> 3) encrypt: I created the sd-encrypt hook, you can find it here:
>>> https://paste.xinu.at/8xUYPI/. This changes the command line syntax, the
>>> new syntax can be found in the manpage for systemd-cryptsetup-generator.
>>> However, the syntax is less powerful than before - for that reason, I
>>> added /etc/crypttab.initrd as /etc/crypttab to the initrd, which should
>>> support almost everything. There were some problems with adding the same
>>> crypttab for initrd and the main system, but that may be my stupiditiy -
>>> I hope the separate crypttab is something we can get rid of.
>>
>> Okay, this one has the wrong help, but otherwise it's what I'm going to
>> use now: https://paste.xinu.at/0PXjlV/
>>
>> It now adds /etc/crypttab to initramfs. You can make sure that only the
>> necessary devices are activated in initramfs by using the rd.luks.uuid=
>> options on the command line. You can also use rd.luks.uuid= without any
>> crypttab entries, but then you can't set extra options (for me:
>> allow_discards).
>
> We should make it possible to do this without having to put
> /etc/crypttab in the initramfs.

What do you think about something like the below (totally untested and
gmail will mess up the linebreaks, but you hopefully get the drift):

commit ff87fedc9b76fc9108eaa9ec1a06c3b0ffac31d4
Author: Tom Gundersen <teg at jklm.no>
Date:   Sun Aug 18 14:59:00 2013 +0800

    cryptsetup-generator: add support for adding options on the kernel
commandline

diff --git a/man/systemd-cryptsetup-generator.xml
b/man/systemd-cryptsetup-generator.xml
index 7950032..2d84d44 100644
--- a/man/systemd-cryptsetup-generator.xml
+++ b/man/systemd-cryptsetup-generator.xml
@@ -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 UUIDs not
+                                specified elsewhere, and without an entry in
+                                /etc/crypttab.</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>
diff --git a/src/cryptsetup/cryptsetup-generator.c
b/src/cryptsetup/cryptsetup-generator.c
index 67460cb..b140f0d 100644
--- a/src/cryptsetup/cryptsetup-generator.c
+++ b/src/cryptsetup/cryptsetup-generator.c
@@ -233,7 +233,7 @@ 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;
@@ -300,6 +300,17 @@ 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);
@@ -332,6 +343,7 @@ 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;
@@ -352,7 +364,7 @@ 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)
@@ -407,6 +419,26 @@ 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
@@ -447,7 +479,7 @@ 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-"))
@@ -462,7 +494,44 @@ 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;
         }


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