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systemd-resolve: easy querying of TLSA records 

$ systemd-resolve --tlsa fedoraproject.org
_443._tcp.fedoraproject.org IN TLSA 0 0 1 GUAL5bejH7czkXcAeJ0vCiRxwMnVBsDlBMBsFtfLF8A=
        -- Cert. usage: CA constraint
        -- Selector: Full Certificate
        -- Matching type: SHA-256

$ systemd-resolve --tlsa=tcp fedoraproject.org:443
_443._tcp.fedoraproject.org IN TLSA 0 0 1 GUAL5bejH7czkXcAeJ0vCiRxwMnVBsDlBMBsFtfLF8A=
        ...

$ systemd-resolve --tlsa=udp fedoraproject.org
_443._udp.fedoraproject.org: resolve call failed: '_443._udp.fedoraproject.org' not found

v2:
- use uint16_t
- refuse port 0
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2016-02-17 21:08:57 -05:00
parent 5259c0559c
commit 82d1d24093
2 changed files with 134 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
man/systemd-resolve.xml
View File

@ -83,6 +83,13 @@
<arg choice="plain"><replaceable>USER@DOMAIN</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<command> --tlsa</command>
<arg choice="plain"><replaceable>DOMAIN<optional>:PORT</optional></replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
@ -121,10 +128,15 @@
is assumed to be a domain name, that is already prefixed with an SRV type, and an SRV lookup is done (no
TXT).</para>
<para>The <option>--openpgp</option> switch may be use to query PGP keys stored as the
<para>The <option>--openpgp</option> switch may be used to query PGP keys stored as
<ulink url="https://tools.ietf.org/html/draft-wouters-dane-openpgp-02">OPENPGPKEY</ulink> resource records.
When this option is specified one or more e-mail address must be specified.</para>
<para>The <option>--tlsa</option> switch maybe be used to query TLS public
keys stored as
<ulink url="https://tools.ietf.org/html/rfc6698">TLSA</ulink> resource records.
When this option is specified one or more domain names must be specified.</para>
<para>The <option>--statistics</option> switch may be used to show resolver statistics, including information about
the number of successful and failed DNSSEC validations.</para>
@ -216,6 +228,20 @@
printed.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--tlsa</option></term>
<listitem><para>Enables TLSA resource record resolution (see above).
A query will be performed for each of the specified names prefixed with
the port and family
(<literal>_<replaceable>port</replaceable>._<replaceable>family</replaceable>.<replaceable>domain</replaceable></literal>).
The port number may be specified after a colon
(<literal>:</literal>), otherwise <constant>443</constant> will be used
by default. The family may be specified as an argument after
<option>--tlsa</option>, otherwise <constant>tcp</constant> will be
used.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--cname=</option><replaceable>BOOL</replaceable></term>
@ -323,6 +349,18 @@ d08ee310438ca124a6149ea5cc21b6313b390dce485576eff96f8722._openpgpkey.fedoraproje
mQINBFBHPMsBEACeInGYJCb+7TurKfb6wGyTottCDtiSJB310i37/6ZYoeIay/5soJjlMyf
MFQ9T2XNT/0LM6gTa0MpC1st9LnzYTMsT6tzRly1D1UbVI6xw0g0vE5y2Cjk3xUwAynCsSs
...
</programlisting>
</example>
<example>
<title>Retrieve a TLS key (<literal>=tcp</literal> and
<literal>:443</literal> could be skipped)</title>
<programlisting>$ systemd-resolve --tlsa=tcp fedoraproject.org:443
_443._tcp.fedoraproject.org IN TLSA 0 0 1 GUAL5bejH7czkXcAeJ0vCiRxwMnVBsDlBMBsFtfLF8A=
-- Cert. usage: CA constraint
-- Selector: Full Certificate
-- Matching type: SHA-256
</programlisting>
</example>
</refsect1>

97
src/resolve/resolve-tool.c
View File

@ -44,12 +44,19 @@ static uint16_t arg_class = 0;
static bool arg_legend = true;
static uint64_t arg_flags = 0;
typedef enum ServiceFamily {
SERVICE_FAMILY_TCP,
SERVICE_FAMILY_UDP,
SERVICE_FAMILY_SCTP,
_SERVICE_FAMILY_INVALID = -1,
} ServiceFamily;
static ServiceFamily arg_service_family = SERVICE_FAMILY_TCP;
typedef enum RawType {
RAW_NONE,
RAW_PAYLOAD,
RAW_PACKET,
} RawType;
static RawType arg_raw = RAW_NONE;
static enum {
@ -57,10 +64,34 @@ static enum {
MODE_RESOLVE_RECORD,
MODE_RESOLVE_SERVICE,
MODE_RESOLVE_OPENPGP,
MODE_RESOLVE_TLSA,
MODE_STATISTICS,
MODE_RESET_STATISTICS,
} arg_mode = MODE_RESOLVE_HOST;
static ServiceFamily service_family_from_string(const char *s) {
if (s == NULL || streq(s, "tcp"))
return SERVICE_FAMILY_TCP;
if (streq(s, "udp"))
return SERVICE_FAMILY_UDP;
if (streq(s, "sctp"))
return SERVICE_FAMILY_SCTP;
return _SERVICE_FAMILY_INVALID;
}
static const char* service_family_to_string(ServiceFamily service) {
switch(service) {
case SERVICE_FAMILY_TCP:
return "_tcp";
case SERVICE_FAMILY_UDP:
return "_udp";
case SERVICE_FAMILY_SCTP:
return "_sctp";
default:
assert_not_reached("invalid service");
}
}
static void print_source(uint64_t flags, usec_t rtt) {
char rtt_str[FORMAT_TIMESTAMP_MAX];
@ -844,6 +875,38 @@ static int resolve_openpgp(sd_bus *bus, const char *address) {
arg_type ?: DNS_TYPE_OPENPGPKEY);
}
static int resolve_tlsa(sd_bus *bus, const char *address) {
const char *port;
uint16_t port_num = 443;
_cleanup_free_ char *full = NULL;
int r;
assert(bus);
assert(address);
port = strrchr(address, ':');
if (port) {
r = safe_atou16(port + 1, &port_num);
if (r < 0 || port_num == 0)
return log_error_errno(r, "Invalid port \"%s\".", port + 1);
address = strndupa(address, port - address);
}
r = asprintf(&full, "_%u.%s.%s",
port_num,
service_family_to_string(arg_service_family),
address);
if (r < 0)
return log_oom();
log_debug("Looking up \"%s\".", full);
return resolve_record(bus, full,
arg_class ?: DNS_CLASS_IN,
arg_type ?: DNS_TYPE_TLSA);
}
static int show_statistics(sd_bus *bus) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
@ -1031,6 +1094,7 @@ static void help(void) {
" --service-address=BOOL Resolve address for services (default: yes)\n"
" --service-txt=BOOL Resolve TXT records for services (default: yes)\n"
" --openpgp Query OpenPGP public key\n"
" --tlsa Query TLS public key\n"
" --cname=BOOL Follow CNAME redirects (default: yes)\n"
" --search=BOOL Use search domains for single-label names\n"
" (default: yes)\n"
@ -1050,6 +1114,7 @@ static int parse_argv(int argc, char *argv[]) {
ARG_SERVICE_ADDRESS,
ARG_SERVICE_TXT,
ARG_OPENPGP,
ARG_TLSA,
ARG_RAW,
ARG_SEARCH,
ARG_STATISTICS,
@ -1069,6 +1134,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "service-address", required_argument, NULL, ARG_SERVICE_ADDRESS },
{ "service-txt", required_argument, NULL, ARG_SERVICE_TXT },
{ "openpgp", no_argument, NULL, ARG_OPENPGP },
{ "tlsa", optional_argument, NULL, ARG_TLSA },
{ "raw", optional_argument, NULL, ARG_RAW },
{ "search", required_argument, NULL, ARG_SEARCH },
{ "statistics", no_argument, NULL, ARG_STATISTICS, },
@ -1183,6 +1249,15 @@ static int parse_argv(int argc, char *argv[]) {
arg_mode = MODE_RESOLVE_OPENPGP;
break;
case ARG_TLSA:
arg_mode = MODE_RESOLVE_TLSA;
arg_service_family = service_family_from_string(optarg);
if (arg_service_family < 0) {
log_error("Unknown service family \"%s\".", optarg);
return -EINVAL;
}
break;
case ARG_RAW:
if (on_tty()) {
log_error("Refusing to write binary data to tty.");
@ -1261,7 +1336,7 @@ static int parse_argv(int argc, char *argv[]) {
return -EINVAL;
}
if (arg_type != 0 && arg_mode != MODE_RESOLVE_RECORD) {
if (arg_type != 0 && arg_mode == MODE_RESOLVE_SERVICE) {
log_error("--service and --type= may not be combined.");
return -EINVAL;
}
@ -1378,6 +1453,24 @@ int main(int argc, char **argv) {
}
break;
case MODE_RESOLVE_TLSA:
if (argc < optind + 1) {
log_error("Domain name required.");
r = -EINVAL;
goto finish;
}
r = 0;
while (optind < argc) {
int k;
k = resolve_tlsa(bus, argv[optind++]);
if (k < 0)
r = k;
}
break;
case MODE_STATISTICS:
if (argc > optind) {
log_error("Too many arguments.");