sd-id128: add new sd_id128_get_machine_app_specific() API
This adds an API for retrieving an app-specific machine ID to sd-id128. Internally it calculates HMAC-SHA256 with an 128bit app-specific ID as payload and the machine ID as key. (An alternative would have been to use siphash for this, which is also cryptographically strong. However, as it only generates 64bit hashes it's not an obvious choice for generating 128bit IDs.) Fixes: #4667
This commit is contained in:
parent
0fe5f3c5d7
commit
70fc4f5790
|
@ -397,6 +397,7 @@ MANPAGES_ALIAS += \
|
||||||
man/sd_id128_from_string.3 \
|
man/sd_id128_from_string.3 \
|
||||||
man/sd_id128_get_boot.3 \
|
man/sd_id128_get_boot.3 \
|
||||||
man/sd_id128_get_invocation.3 \
|
man/sd_id128_get_invocation.3 \
|
||||||
|
man/sd_id128_get_machine_app_specific.3 \
|
||||||
man/sd_id128_is_null.3 \
|
man/sd_id128_is_null.3 \
|
||||||
man/sd_id128_t.3 \
|
man/sd_id128_t.3 \
|
||||||
man/sd_is_mq.3 \
|
man/sd_is_mq.3 \
|
||||||
|
@ -750,6 +751,7 @@ man/sd_id128_equal.3: man/sd-id128.3
|
||||||
man/sd_id128_from_string.3: man/sd_id128_to_string.3
|
man/sd_id128_from_string.3: man/sd_id128_to_string.3
|
||||||
man/sd_id128_get_boot.3: man/sd_id128_get_machine.3
|
man/sd_id128_get_boot.3: man/sd_id128_get_machine.3
|
||||||
man/sd_id128_get_invocation.3: man/sd_id128_get_machine.3
|
man/sd_id128_get_invocation.3: man/sd_id128_get_machine.3
|
||||||
|
man/sd_id128_get_machine_app_specific.3: man/sd_id128_get_machine.3
|
||||||
man/sd_id128_is_null.3: man/sd-id128.3
|
man/sd_id128_is_null.3: man/sd-id128.3
|
||||||
man/sd_id128_t.3: man/sd-id128.3
|
man/sd_id128_t.3: man/sd-id128.3
|
||||||
man/sd_is_mq.3: man/sd_is_fifo.3
|
man/sd_is_mq.3: man/sd_is_fifo.3
|
||||||
|
@ -1531,6 +1533,9 @@ man/sd_id128_get_boot.html: man/sd_id128_get_machine.html
|
||||||
man/sd_id128_get_invocation.html: man/sd_id128_get_machine.html
|
man/sd_id128_get_invocation.html: man/sd_id128_get_machine.html
|
||||||
$(html-alias)
|
$(html-alias)
|
||||||
|
|
||||||
|
man/sd_id128_get_machine_app_specific.html: man/sd_id128_get_machine.html
|
||||||
|
$(html-alias)
|
||||||
|
|
||||||
man/sd_id128_is_null.html: man/sd-id128.html
|
man/sd_id128_is_null.html: man/sd-id128.html
|
||||||
$(html-alias)
|
$(html-alias)
|
||||||
|
|
||||||
|
|
|
@ -71,13 +71,14 @@
|
||||||
<para>This machine ID adheres to the same format and logic as the
|
<para>This machine ID adheres to the same format and logic as the
|
||||||
D-Bus machine ID.</para>
|
D-Bus machine ID.</para>
|
||||||
|
|
||||||
<para>This ID uniquely identifies the host. It should be considered "confidential", and must not
|
<para>This ID uniquely identifies the host. It should be considered "confidential", and must not be exposed in
|
||||||
be exposed in untrusted environments, in particular on the network. If a stable unique
|
untrusted environments, in particular on the network. If a stable unique identifier that is tied to the machine is
|
||||||
identifier that is tied to the machine is needed for some application, the machine ID or any
|
needed for some application, the machine ID or any part of it must not be used directly. Instead the machine ID
|
||||||
part of it must not be used directly. Instead the machine ID should be hashed with a
|
should be hashed with a cryptographic, keyed hash function, using a fixed, application-specific key. That way the
|
||||||
cryptographic, keyed hash function, using a fixed, application-specific key. That way the ID
|
ID will be properly unique, and derived in a constant way from the machine ID but there will be no way to retrieve
|
||||||
will be properly unique, and derived in a constant way from the machine ID but there will be no
|
the original machine ID from the application-specific one. The
|
||||||
way to retrieve the original machine ID from the application-specific one.</para>
|
<citerefentry><refentrytitle>sd_id128_get_machine_app_specific</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||||||
|
API provides an implementation of such an algorithm.</para>
|
||||||
|
|
||||||
<para>The
|
<para>The
|
||||||
<citerefentry><refentrytitle>systemd-machine-id-setup</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
<citerefentry><refentrytitle>systemd-machine-id-setup</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
||||||
|
|
|
@ -44,6 +44,7 @@
|
||||||
|
|
||||||
<refnamediv>
|
<refnamediv>
|
||||||
<refname>sd_id128_get_machine</refname>
|
<refname>sd_id128_get_machine</refname>
|
||||||
|
<refname>sd_id128_get_machine_app_specific</refname>
|
||||||
<refname>sd_id128_get_boot</refname>
|
<refname>sd_id128_get_boot</refname>
|
||||||
<refname>sd_id128_get_invocation</refname>
|
<refname>sd_id128_get_invocation</refname>
|
||||||
<refpurpose>Retrieve 128-bit IDs</refpurpose>
|
<refpurpose>Retrieve 128-bit IDs</refpurpose>
|
||||||
|
@ -58,6 +59,12 @@
|
||||||
<paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
|
<paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
|
||||||
</funcprototype>
|
</funcprototype>
|
||||||
|
|
||||||
|
<funcprototype>
|
||||||
|
<funcdef>int <function>sd_id128_get_machine_app_specific</function></funcdef>
|
||||||
|
<paramdef>sd_id128_t <parameter>app_id</parameter></paramdef>
|
||||||
|
<paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
|
||||||
|
</funcprototype>
|
||||||
|
|
||||||
<funcprototype>
|
<funcprototype>
|
||||||
<funcdef>int <function>sd_id128_get_boot</function></funcdef>
|
<funcdef>int <function>sd_id128_get_boot</function></funcdef>
|
||||||
<paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
|
<paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
|
||||||
|
@ -74,11 +81,22 @@
|
||||||
<refsect1>
|
<refsect1>
|
||||||
<title>Description</title>
|
<title>Description</title>
|
||||||
|
|
||||||
<para><function>sd_id128_get_machine()</function> returns the
|
<para><function>sd_id128_get_machine()</function> returns the machine ID of the executing host. This reads and
|
||||||
machine ID of the executing host. This reads and parses the
|
parses the <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
||||||
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
file. This function caches the machine ID internally to make retrieving the machine ID a cheap operation. This ID
|
||||||
file. This function caches the machine ID internally to make
|
may be used wherever a unique identifier for the local system is needed. However, it is recommended to use this ID
|
||||||
retrieving the machine ID a cheap operation.</para>
|
as-is only in trusted environments. In untrusted environments it is recommended to derive an application specific
|
||||||
|
ID from this machine ID, in an irreversable (cryptographically secure) way. To make this easy
|
||||||
|
<function>sd_id128_get_machine_app_specific()</function> is provided, see below.</para>
|
||||||
|
|
||||||
|
<para><function>sd_id128_get_machine_app_specific()</function> is similar to
|
||||||
|
<function>sd_id128_get_machine()</function>, but retrieves a machine ID that is specific to the application that is
|
||||||
|
identified by the indicated application ID. It is recommended to use this function instead of
|
||||||
|
<function>sd_id128_get_machine()</function> when passing an ID to untrusted environments, in order to make sure
|
||||||
|
that the original machine ID may not be determined externally. The application-specific ID should be generated via
|
||||||
|
a tool like <command>journalctl --new-id128</command>, and may be compiled into the application. This function will
|
||||||
|
return the same application-specific ID for each combination of machine ID and application ID. Internally, this
|
||||||
|
function calculates HMAC-SHA256 of the application ID, keyed by the machine ID.</para>
|
||||||
|
|
||||||
<para><function>sd_id128_get_boot()</function> returns the boot ID
|
<para><function>sd_id128_get_boot()</function> returns the boot ID
|
||||||
of the executing kernel. This reads and parses the
|
of the executing kernel. This reads and parses the
|
||||||
|
@ -95,10 +113,10 @@
|
||||||
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details. The
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details. The
|
||||||
ID is cached internally. In future a different mechanism to determine the invocation ID may be added.</para>
|
ID is cached internally. In future a different mechanism to determine the invocation ID may be added.</para>
|
||||||
|
|
||||||
<para>Note that <function>sd_id128_get_boot()</function> and <function>sd_id128_get_invocation()</function> always
|
<para>Note that <function>sd_id128_get_machine_app_specific()</function>, <function>sd_id128_get_boot()</function>
|
||||||
return UUID v4 compatible IDs. <function>sd_id128_get_machine()</function> will also return a UUID v4-compatible
|
and <function>sd_id128_get_invocation()</function> always return UUID v4 compatible IDs.
|
||||||
ID on new installations but might not on older. It is possible to convert the machine ID into a UUID v4-compatible
|
<function>sd_id128_get_machine()</function> will also return a UUID v4-compatible ID on new installations but might
|
||||||
one. For more information, see
|
not on older. It is possible to convert the machine ID into a UUID v4-compatible one. For more information, see
|
||||||
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
|
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
|
||||||
|
|
||||||
<para>For more information about the <literal>sd_id128_t</literal>
|
<para>For more information about the <literal>sd_id128_t</literal>
|
||||||
|
@ -117,12 +135,35 @@
|
||||||
<refsect1>
|
<refsect1>
|
||||||
<title>Notes</title>
|
<title>Notes</title>
|
||||||
|
|
||||||
<para>The <function>sd_id128_get_machine()</function>, <function>sd_id128_get_boot()</function> and
|
<para>The <function>sd_id128_get_machine()</function>, <function>sd_id128_get_machine_app_specific()</function>
|
||||||
<function>sd_id128_get_invocation()</function> interfaces are available as a shared library, which can be compiled
|
<function>sd_id128_get_boot()</function> and <function>sd_id128_get_invocation()</function> interfaces are
|
||||||
and linked to with the <literal>libsystemd</literal> <citerefentry
|
available as a shared library, which can be compiled and linked to with the
|
||||||
|
<literal>libsystemd</literal> <citerefentry
|
||||||
project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para>
|
project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para>
|
||||||
</refsect1>
|
</refsect1>
|
||||||
|
|
||||||
|
<refsect1>
|
||||||
|
<title>Examples</title>
|
||||||
|
|
||||||
|
<example>
|
||||||
|
<title>Application-specific machine ID</title>
|
||||||
|
|
||||||
|
<para>Here's a simple example for an application specific machine ID:</para>
|
||||||
|
|
||||||
|
<programlisting>#include <systemd/sd-id128.h>
|
||||||
|
#include <stdio.h>
|
||||||
|
|
||||||
|
#define OUR_APPLICATION_ID SD_ID128_MAKE(c2,73,27,73,23,db,45,4e,a6,3b,b9,6e,79,b5,3e,97)
|
||||||
|
|
||||||
|
int main(int argc, char *argv[]) {
|
||||||
|
sd_id128_t id;
|
||||||
|
sd_id128_get_machine_app_specific(OUR_APPLICATION_ID, &id);
|
||||||
|
printf("Our application ID: " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(id));
|
||||||
|
return 0;
|
||||||
|
}</programlisting>
|
||||||
|
</example>
|
||||||
|
</refsect1>
|
||||||
|
|
||||||
<refsect1>
|
<refsect1>
|
||||||
<title>See Also</title>
|
<title>See Also</title>
|
||||||
|
|
||||||
|
|
|
@ -511,3 +511,8 @@ global:
|
||||||
sd_bus_get_exit_on_disconnect;
|
sd_bus_get_exit_on_disconnect;
|
||||||
sd_id128_get_invocation;
|
sd_id128_get_invocation;
|
||||||
} LIBSYSTEMD_231;
|
} LIBSYSTEMD_231;
|
||||||
|
|
||||||
|
LIBSYSTEMD_233 {
|
||||||
|
global:
|
||||||
|
sd_id128_get_machine_app_specific;
|
||||||
|
} LIBSYSTEMD_232;
|
||||||
|
|
|
@ -27,6 +27,7 @@
|
||||||
#include "hexdecoct.h"
|
#include "hexdecoct.h"
|
||||||
#include "id128-util.h"
|
#include "id128-util.h"
|
||||||
#include "io-util.h"
|
#include "io-util.h"
|
||||||
|
#include "khash.h"
|
||||||
#include "macro.h"
|
#include "macro.h"
|
||||||
#include "random-util.h"
|
#include "random-util.h"
|
||||||
#include "util.h"
|
#include "util.h"
|
||||||
|
@ -181,3 +182,34 @@ _public_ int sd_id128_randomize(sd_id128_t *ret) {
|
||||||
*ret = make_v4_uuid(t);
|
*ret = make_v4_uuid(t);
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
_public_ int sd_id128_get_machine_app_specific(sd_id128_t app_id, sd_id128_t *ret) {
|
||||||
|
_cleanup_(khash_unrefp) khash *h = NULL;
|
||||||
|
sd_id128_t m, result;
|
||||||
|
const void *p;
|
||||||
|
int r;
|
||||||
|
|
||||||
|
assert_return(ret, -EINVAL);
|
||||||
|
|
||||||
|
r = sd_id128_get_machine(&m);
|
||||||
|
if (r < 0)
|
||||||
|
return r;
|
||||||
|
|
||||||
|
r = khash_new_with_key(&h, "hmac(sha256)", &m, sizeof(m));
|
||||||
|
if (r < 0)
|
||||||
|
return r;
|
||||||
|
|
||||||
|
r = khash_put(h, &app_id, sizeof(app_id));
|
||||||
|
if (r < 0)
|
||||||
|
return r;
|
||||||
|
|
||||||
|
r = khash_digest_data(h, &p);
|
||||||
|
if (r < 0)
|
||||||
|
return r;
|
||||||
|
|
||||||
|
/* We chop off the trailing 16 bytes */
|
||||||
|
memcpy(&result, p, MIN(khash_get_size(h), sizeof(result)));
|
||||||
|
|
||||||
|
*ret = make_v4_uuid(result);
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
|
@ -39,12 +39,12 @@ union sd_id128 {
|
||||||
#define SD_ID128_STRING_MAX 33
|
#define SD_ID128_STRING_MAX 33
|
||||||
|
|
||||||
char *sd_id128_to_string(sd_id128_t id, char s[SD_ID128_STRING_MAX]);
|
char *sd_id128_to_string(sd_id128_t id, char s[SD_ID128_STRING_MAX]);
|
||||||
|
|
||||||
int sd_id128_from_string(const char *s, sd_id128_t *ret);
|
int sd_id128_from_string(const char *s, sd_id128_t *ret);
|
||||||
|
|
||||||
int sd_id128_randomize(sd_id128_t *ret);
|
int sd_id128_randomize(sd_id128_t *ret);
|
||||||
|
|
||||||
int sd_id128_get_machine(sd_id128_t *ret);
|
int sd_id128_get_machine(sd_id128_t *ret);
|
||||||
|
int sd_id128_get_machine_app_specific(sd_id128_t app_id, sd_id128_t *ret);
|
||||||
int sd_id128_get_boot(sd_id128_t *ret);
|
int sd_id128_get_boot(sd_id128_t *ret);
|
||||||
int sd_id128_get_invocation(sd_id128_t *ret);
|
int sd_id128_get_invocation(sd_id128_t *ret);
|
||||||
|
|
||||||
|
|
|
@ -153,5 +153,11 @@ int main(int argc, char *argv[]) {
|
||||||
assert_se(id128_read_fd(fd, ID128_UUID, &id2) >= 0);
|
assert_se(id128_read_fd(fd, ID128_UUID, &id2) >= 0);
|
||||||
assert_se(sd_id128_equal(id, id2));
|
assert_se(sd_id128_equal(id, id2));
|
||||||
|
|
||||||
|
assert_se(sd_id128_get_machine_app_specific(SD_ID128_MAKE(f0,3d,aa,eb,1c,33,4b,43,a7,32,17,29,44,bf,77,2e), &id) >= 0);
|
||||||
|
assert_se(sd_id128_get_machine_app_specific(SD_ID128_MAKE(f0,3d,aa,eb,1c,33,4b,43,a7,32,17,29,44,bf,77,2e), &id2) >= 0);
|
||||||
|
assert_se(sd_id128_equal(id, id2));
|
||||||
|
assert_se(sd_id128_get_machine_app_specific(SD_ID128_MAKE(51,df,0b,4b,c3,b0,4c,97,80,e2,99,b9,8c,a3,73,b8), &id2) >= 0);
|
||||||
|
assert_se(!sd_id128_equal(id, id2));
|
||||||
|
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
Loading…
Reference in New Issue