Browse Source

Import upstream version 7

Nathaniel McCallum 3 years ago
commit
b2c236cfe5
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      COPYING
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COPYING

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+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.

+ 4 - 0
README.md

@@ -0,0 +1,4 @@
+# nagios-tang
+A Nagios plugin to check the health of the Tang server
+
+For more information see the [documentation](nagios-tang.1.adoc).

+ 81 - 0
meson.build

@@ -0,0 +1,81 @@
+project('nagios-tang', 'c', license: 'GPL3+', version: '7',
+        default_options: 'c_std=c99')
+
+add_project_arguments(
+  '-Wall',
+  '-Wextra',
+  '-Werror',
+  '-Wstrict-aliasing',
+  '-Wchar-subscripts',
+  '-Wformat-security',
+  '-Wmissing-declarations',
+  '-Wmissing-prototypes',
+  '-Wnested-externs',
+  '-Wpointer-arith',
+  '-Wshadow',
+  '-Wsign-compare',
+  '-Wstrict-prototypes',
+  '-Wtype-limits',
+  '-Wunused-function',
+  '-Wno-missing-field-initializers',
+  '-Wno-unused-command-line-argument',
+  '-Wno-unused-parameter',
+  '-Wno-unknown-pragmas',
+  language: 'c'
+)
+
+libexecdir = join_paths(get_option('prefix'), get_option('libexecdir'))
+
+http = meson.get_compiler('c').find_library('http_parser')
+jose = dependency('jose', version: '>=8')
+
+actv = find_program('systemd-socket-activate', required: false)
+tang = find_program([
+  join_paths(libexecdir, 'tangd'),
+  '/usr/libexec/tangd',
+  '/usr/local/libexec/tangd',
+], required: false)
+kgen = find_program([
+  join_paths(libexecdir, 'tangd-keygen'),
+  '/usr/libexec/tangd-keygen',
+  '/usr/local/libexec/tangd-keygen',
+], required: false)
+updt = find_program([
+  join_paths(libexecdir, 'tangd-update'),
+  '/usr/libexec/tangd-update',
+  '/usr/local/libexec/tangd-update',
+], required: false)
+
+if tang.found() and kgen.found() and updt.found() and actv.found()
+  env = environment()
+  env.append('PATH',
+    meson.current_build_dir(),
+    libexecdir,
+    '/usr/libexec',
+    '/usr/local/libexec',
+    separator: ':'
+  )
+
+  test('tang', find_program(meson.current_source_dir() + '/tang'), env: env)
+else
+  warning('Will not run tests due to missing dependencies!')
+endif
+
+a2x = find_program('a2x', required: false)
+if a2x.found()
+  custom_target('nagios-tang.1',
+    command: [a2x, '-f', 'manpage', '-D', meson.current_build_dir(), '@INPUT@'],
+    install_dir: join_paths(get_option('mandir'), 'man1'),
+    input: 'nagios-tang.1.adoc',
+    output: 'nagios-tang.1',
+    install: true,
+  )
+else
+  warning('Will not install man page due to missing dependencies!')
+endif
+
+executable('tang', 'tang.c',
+  install_dir: join_paths(get_option('libdir'), 'nagios', 'plugins'),
+  dependencies: [http, jose],
+  install: true,
+)

+ 48 - 0
nagios-tang.1.adoc

@@ -0,0 +1,48 @@
+nagios-tang(1)
+==============
+:doctype: manpage
+
+== NAME
+
+nagios-tang - A Nagios plugin for Tang
+
+== SYNOPSIS
+
+*tang* -u URL
+
+== OVERVIEW
+
+This Nagios plugin for Tang enables Nagios to monitor a Tang server for its
+basic functionality as well as performance metrics. The plugin is executed
+simply by providing the base URL to the Tang service.
+
+The plugin will test the following functionality:
+
+1. Downloading the advertisement.
+2. Verification of advertisement semantics.
+3. Verification of signatures for all advertised signing keys.
+4. Verification of key exchanges for all advertised exchange keys.
+
+If any of these tests fail, an error will be generated. Upon success, the
+plugin will output the following performance metrics:
+
+* *adv*   : Time it took to fetch the advertisement (in μs).
+* *exc*   : Average time of all key exchange operations (in μs).
+* *nkeys* : Number of keys in the advertisement.
+* *nsigk* : Number of signing keys in the advertisement.
+* *nexck* : Number of exchange keys in the advertisement.
+
+== EXAMPLES
+
+A simple test against a localhost Tang server:
+
+    $ ./tang -u http://localhost/
+    OK|adv=21430 exc=44587 nkeys=2 nsigk=1 nexck=1
+
+== AUTHOR
+
+Nathaniel McCallum <npmccallum@redhat.com>
+
+== SEE ALSO
+
+link:tang.8.adoc[*tang*(8)]

+ 43 - 0
tang

@@ -0,0 +1,43 @@
+#!/bin/bash -x
+# vim: set tabstop=8 shiftwidth=4 softtabstop=4 expandtab smarttab colorcolumn=80:
+#
+# Copyright (c) 2016 Red Hat, Inc.
+# Author: Nathaniel McCallum <npmccallum@redhat.com>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+function on_exit() {
+    if [ "$PID" ]; then kill $PID; wait $PID || true; fi
+    [ -d "$TMP" ] && rm -rf $TMP
+}
+
+trap 'on_exit' EXIT
+trap 'exit' ERR
+
+export TMP=`mktemp -d`
+mkdir -p $TMP/db
+mkdir -p $TMP/cache
+
+# Generate the server keys
+tangd-keygen $TMP/db
+tangd-update $TMP/db $TMP/cache
+
+# Start the server
+port=`shuf -i 1024-65536 -n 1`
+systemd-socket-activate --inet -l 127.0.0.1:$port -a $VALGRIND tangd $TMP/cache &
+export PID=$!
+sleep 0.5
+
+tang -u http://127.0.0.1:$port

+ 552 - 0
tang.c

@@ -0,0 +1,552 @@
+/* vim: set tabstop=8 shiftwidth=4 softtabstop=4 expandtab smarttab colorcolumn=80: */
+/*
+ * Copyright (c) 2016 Red Hat, Inc.
+ * Author: Nathaniel McCallum <npmccallum@redhat.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * NOTE WELL: This code is completely insecure for real-world workflows!
+ *
+ * In particular, it has two glaring security problems:
+ *
+ *   1. Server keys are implicitly trusted.
+ *   2. No ephemeral keys are used to protect the recovery phase.
+ *
+ * However, the goal of this Nagios plugin is to determine if the server is
+ * alive and properly handles well-formed requests. So we don't care about
+ * security. If you are looking for an example of how to securely use Tang,
+ * check out the Clevis project.
+ */
+
+#define _GNU_SOURCE
+
+#include <http_parser.h>
+#include <jose/jose.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+
+#include <errno.h>
+#include <getopt.h>
+#include <limits.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#define conn_auto_t conn_t __attribute__((cleanup(conn_cleanup)))
+
+enum {
+    NAGIOS_OK = 0,
+    NAGIOS_WARN = 1,
+    NAGIOS_CRIT = 2,
+    NAGIOS_UNKN = 3
+};
+
+typedef struct {
+    char data[4096];
+    size_t used;
+    int sock;
+} conn_t;
+
+typedef struct {
+    char *data;
+    size_t size;
+} body_t;
+
+typedef struct {
+    char schm[PATH_MAX];
+    char host[PATH_MAX];
+    char srvc[PATH_MAX];
+    char path[PATH_MAX];
+} url_t;
+
+static void
+conn_cleanup(conn_t **conn)
+{
+    if (conn && *conn) {
+        close((*conn)->sock);
+        free(*conn);
+    }
+}
+
+static conn_t *
+conn_open(const char *host, const char *srvc, int family)
+{
+    const struct addrinfo hint = {
+        .ai_socktype = SOCK_STREAM,
+        .ai_family = family,
+    };
+
+    struct addrinfo *ais = NULL;
+    conn_t *conn = NULL;
+    int sock = -1;
+
+    sock = getaddrinfo(host, srvc, &hint, &ais);
+    switch (sock) {
+        case 0: break;
+        case EAI_AGAIN:    errno = -EAGAIN;  return NULL;
+        case EAI_BADFLAGS: errno = -EINVAL;  return NULL;
+        case EAI_FAMILY:   errno = -ENOTSUP; return NULL;
+        case EAI_MEMORY:   errno = -ENOMEM;  return NULL;
+        case EAI_SERVICE:  errno = -EINVAL;  return NULL;
+        default:           errno = -EIO;     return NULL;
+    }
+
+    conn = calloc(1, sizeof(*conn));
+    if (!conn) {
+        freeaddrinfo(ais);
+        return NULL;
+    }
+
+    for (const struct addrinfo *ai = ais; ai; ai = ai->ai_next) {
+        conn->sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+        if (conn->sock < 0)
+            continue;
+
+        if (connect(conn->sock, ai->ai_addr, ai->ai_addrlen) != 0) {
+            close(conn->sock);
+            continue;
+        }
+
+        freeaddrinfo(ais);
+        return conn;
+    }
+
+    freeaddrinfo(ais);
+    free(conn);
+
+    errno = -ENOENT;
+    return NULL;
+}
+
+static int
+conn_send(const conn_t *conn, const char *fmt, ...)
+{
+    va_list ap;
+    int r;
+
+    va_start(ap, fmt);
+    r = vdprintf(conn->sock, fmt, ap);
+    va_end(ap);
+    return r;
+}
+
+static int
+on_body(http_parser *parser, const char *at, size_t length)
+{
+    body_t *body = parser->data;
+    char *tmp = NULL;
+
+    tmp = realloc(body->data, body->size + length + 1);
+    if (!tmp)
+        return -errno;
+
+    memcpy(&tmp[body->size], at, length);
+    body->size += length;
+    body->data = tmp;
+
+    body->data[body->size] = 0;
+    return 0;
+}
+
+static int
+on_message_complete(http_parser *parser)
+{
+    http_parser_pause(parser, true);
+    return 0;
+}
+
+static int
+conn_recv(conn_t *conn, char **body)
+{
+    static const http_parser_settings settings = {
+        .on_body = on_body,
+        .on_message_complete = on_message_complete
+    };
+
+    body_t data = {};
+    http_parser parser = { .data = &data };
+
+    http_parser_init(&parser, HTTP_RESPONSE);
+
+    for (;;) {
+        ssize_t rcvd = 0;
+        size_t prsd = 0;
+
+        rcvd = recv(conn->sock, &conn->data[conn->used],
+                    sizeof(conn->data) - conn->used, 0);
+        if (rcvd < 0) {
+            free(data.data);
+            return -errno;
+        } else if (rcvd == 0) {
+            free(data.data);
+            return -EIO;
+        }
+
+        conn->used += rcvd;
+
+        prsd = http_parser_execute(&parser, &settings, conn->data, conn->used);
+
+        conn->used -= prsd;
+        memmove(conn->data, &conn->data[prsd], conn->used);
+
+        switch (parser.http_errno) {
+        case HPE_OK: /* We need to process more data. */
+            break;
+
+        case HPE_PAUSED: /* We got one request. */
+            *body = data.data;
+            return parser.status_code;
+
+        default: /* An error occurred. */
+            free(data.data);
+            return -EBADMSG;
+        }
+    }
+}
+
+static double
+curtime(void)
+{
+    struct timespec ts = {};
+    double out = 0;
+
+    if (clock_gettime(CLOCK_MONOTONIC_RAW, &ts) == 0) {
+        out = ts.tv_nsec;
+        out /= 1000000000L;
+        out += ts.tv_sec;
+    }
+
+    return out;
+}
+
+static void
+dump_perf(json_t *time)
+{
+    const char *key = NULL;
+    bool first = true;
+    json_t *val = 0;
+
+    json_object_foreach(time, key, val) {
+        int v = 0;
+
+        if (!first)
+            printf(" ");
+        else
+            first = false;
+
+        if (json_is_integer(val))
+            v = json_integer_value(val);
+        else if (json_is_real(val))
+            v = json_real_value(val) * 1000000;
+
+        printf("%s=%d", key, v);
+    }
+}
+
+static int
+parse_url(const char *url, url_t *parts)
+{
+    static const uint16_t mask = (1 << UF_SCHEMA) | (1 << UF_HOST);
+    struct http_parser_url purl = {};
+
+    if (http_parser_parse_url(url, strlen(url), false, &purl) != 0)
+        return -EINVAL;
+
+    if ((purl.field_set & mask) != mask)
+        return -EINVAL;
+
+    if (purl.field_data[UF_SCHEMA].len >= sizeof(parts->schm) ||
+        purl.field_data[UF_HOST].len >= sizeof(parts->host) ||
+        purl.field_data[UF_PORT].len >= sizeof(parts->srvc) ||
+        purl.field_data[UF_PATH].len >= sizeof(parts->path))
+        return -E2BIG;
+
+    strncpy(parts->schm, &url[purl.field_data[UF_SCHEMA].off],
+            purl.field_data[UF_SCHEMA].len);
+
+    strncpy(parts->host, &url[purl.field_data[UF_HOST].off],
+            purl.field_data[UF_HOST].len);
+
+    if (purl.field_set & (1 << UF_PORT)) {
+        strncpy(parts->srvc, &url[purl.field_data[UF_PORT].off],
+                purl.field_data[UF_PORT].len);
+    } else {
+        strcpy(parts->srvc, parts->schm);
+    }
+
+    if (purl.field_set & (1 << UF_PATH)) {
+        strncpy(parts->path, &url[purl.field_data[UF_PATH].off],
+                purl.field_data[UF_PATH].len);
+    }
+
+    return 0;
+}
+
+static json_t *
+validate(const json_t *jws)
+{
+    json_auto_t *jwkset = NULL;
+    json_t *keys = NULL;
+    size_t sigs = 0;
+
+    jwkset = jose_b64_dec_load(json_object_get(jws, "payload"));
+    if (!jwkset)
+        return NULL;
+
+    keys = json_object_get(jwkset, "keys");
+    if (!json_is_array(keys))
+        return NULL;
+
+    for (size_t i = 0; i < json_array_size(keys); i++) {
+        json_t *key = json_array_get(keys, i);
+
+        if (!jose_jwk_prm(NULL, key, true, "verify"))
+            continue;
+
+        if (!jose_jws_ver(NULL, jws, NULL, key, true))
+            return NULL;
+
+        sigs++;
+    }
+
+    if (sigs == 0)
+        return NULL;
+
+    return json_incref(keys);
+}
+
+static bool
+nagios_recover(conn_t *con, const char *host, const char *path,
+               const json_t *jwk, size_t *sig, size_t *rec, json_t *time)
+{
+    json_auto_t *exc = NULL;
+    json_auto_t *rep = NULL;
+    json_auto_t *lcl = NULL;
+    json_auto_t *kid = NULL;
+    char *body = NULL;
+    double s = 0;
+    double e = 0;
+    int r = 0;
+
+    if (jose_jwk_prm(NULL, jwk, true, "verify")) {
+        *sig += 1;
+        return true;
+    }
+
+    if (!jose_jwk_prm(NULL, jwk, true, "deriveKey"))
+        return true;
+
+    kid = jose_jwk_thp(NULL, jwk, "S256");
+    if (!kid)
+        return true;
+
+    lcl = json_pack("{s:O,s:O,s:s,s:[s]}",
+                    "kty", json_object_get(jwk, "kty"),
+                    "crv", json_object_get(jwk, "crv"),
+                    "alg", "ECMR",
+                    "key_ops", "deriveKey");
+    if (!lcl)
+        return false;
+
+    if (!jose_jwk_gen(NULL, lcl))
+        return false;
+
+    exc = jose_jwk_exc(NULL, lcl, jwk);
+    if (!exc)
+        return false;
+
+    if (!jose_jwk_pub(NULL, lcl))
+        return false;
+
+    body = json_dumps(lcl, JSON_SORT_KEYS | JSON_COMPACT);
+    if (!body)
+        return false;
+
+    r = conn_send(con,
+                  "POST %s/rec/%s HTTP/1.1\r\n"
+                  "Content-Type: application/jwk+json\r\n"
+                  "Accept: application/jwk+json\r\n"
+                  "Content-Length: %zu\r\n"
+                  "Host: %s\r\n"
+                  "\r\n%s",
+                  path, json_string_value(kid), strlen(body), host, body);
+    free(body);
+    body = NULL;
+    if (r < 0)
+        return false;
+
+    s = curtime();
+    r = conn_recv(con, &body);
+    e = curtime();
+    if (r != 200) {
+        if (r < 0)
+            printf("Error performing recovery! %s\n", strerror(-r));
+        else
+            printf("Error performing recovery! HTTP Status %d\n", r);
+
+        free(body);
+        return false;
+    }
+
+    rep = json_loads(body, 0, NULL);
+    free(body);
+    if (!rep) {
+        printf("Received invalid JSON in response body!\n");
+        return false;
+    }
+
+    if (s == 0.0 || e == 0.0 ||
+        json_array_append_new(time, json_real(e - s)) < 0) {
+        printf("Error calculating performance metrics!\n");
+        return false;
+    }
+
+    if (!jose_jwk_eql(NULL, exc, rep)) {
+        printf("Recovered key doesn't match!\n");
+        return false;
+    }
+
+    *rec += 1;
+    return true;
+}
+
+static const struct option opts[] = {
+    { "help",   no_argument,      .val = INT_MAX },
+    { "url",   required_argument, .val = 'u' },
+    {}
+};
+
+int
+main(int argc, char *argv[])
+{
+    json_auto_t *perf = NULL;
+    json_auto_t *time = NULL;
+    json_auto_t *keys = NULL;
+    json_auto_t *adv = NULL;
+    conn_auto_t *con = NULL;
+    const char *url = NULL;
+    char *body = NULL;
+    url_t parts = {};
+    size_t sig = 0;
+    size_t exc = 0;
+    double sum = 0;
+    double s = 0;
+    double e = 0;
+    int r = 0;
+
+    perf = json_object();
+    time = json_array();
+    if (!perf || !time)
+        return NAGIOS_CRIT;
+
+    for (int c; (c = getopt_long(argc, argv, "u:", opts, NULL)) >= 0; ) {
+        switch (c) {
+        case 'u': url = optarg; break;
+        default: goto usage;
+        }
+    }
+
+    if (!url)
+        goto usage;
+
+    r = parse_url(url, &parts);
+    if (r < 0)
+        return NAGIOS_CRIT;
+
+    con = conn_open(parts.host, parts.srvc, AF_UNSPEC);
+    if (!con) {
+        printf("Unable to connect to server!\n");
+        return NAGIOS_CRIT;
+    }
+
+    r = conn_send(con,
+                  "GET %s/adv HTTP/1.1\r\n"
+                  "Accept: application/jose+json\r\n"
+                  "Content-Length: 0\r\n"
+                  "Host: %s\r\n"
+                  "\r\n", parts.path, parts.host);
+    if (r < 0)
+        return NAGIOS_CRIT;
+
+    s = curtime();
+    r = conn_recv(con, &body);
+    e = curtime();
+    if (r != 200) {
+        if (r < 0)
+            printf("Error fetching advertisement! %s\n", strerror(-r));
+        else
+            printf("Error fetching advertisement! HTTP Status %d\n", r);
+
+        free(body);
+        return NAGIOS_CRIT;
+    }
+
+    if (s == 0.0 || e == 0.0 ||
+        json_object_set_new(perf, "adv", json_real(e - s)) != 0) {
+        printf("Error calculating performance metrics!\n");
+        free(body);
+        return NAGIOS_CRIT;
+    }
+
+    adv = json_loads(body, 0, NULL);
+    free(body);
+    if (!adv) {
+        printf("Received invalid advertisement!\n");
+        return NAGIOS_CRIT;
+    }
+
+    keys = validate(adv);
+    if (!keys) {
+        printf("Error validating advertisement!\n");
+        return NAGIOS_CRIT;
+    }
+
+    for (size_t i = 0; i < json_array_size(keys); i++) {
+        json_t *jwk = json_array_get(keys, i);
+        if (!nagios_recover(con, parts.host, parts.path, jwk,
+                            &sig, &exc, time))
+            return NAGIOS_CRIT;
+    }
+
+    if (exc == 0) {
+        printf("Advertisement contains no exchange keys!\n");
+        return NAGIOS_CRIT;
+    }
+
+    for (size_t i = 0; i < json_array_size(time); i++)
+        sum += json_real_value(json_array_get(time, i));
+
+    json_object_set_new(perf, "exc", json_real(sum / json_array_size(time)));
+    json_object_set_new(perf, "nkeys", json_integer(json_array_size(keys)));
+    json_object_set_new(perf, "nsigk", json_integer(sig));
+    json_object_set_new(perf, "nexck", json_integer(exc));
+
+    printf("OK|");
+    dump_perf(perf);
+    printf("\n");
+    return NAGIOS_OK;
+
+usage:
+    fprintf(stderr,
+            "Usage: %s -u URL\n"
+            "\n"
+            "            --help       Show this usage message\n"
+            "    -u URL, --url URL    Test the server at this URL\n"
+            "", argv[0]);
+    return NAGIOS_CRIT;
+}