2 * Copyright (C) 2018 Daniel Golle <daniel@makrotopia.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 3
6 * as published by the Free Software Foundation
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
30 #include <json-c/json.h>
31 #include <libubox/blob.h>
32 #include <libubox/utils.h>
33 #include <libubox/list.h>
34 #include <libubox/vlist.h>
35 #include <libubox/blobmsg_json.h>
39 #define CERT_BUF_LEN 4096
51 #ifndef UCERT_STRIP_MESSAGES
52 #define DPRINTF(format, ...) \
55 fprintf(stderr, "%s(%d): " format, __func__, __LINE__, ## __VA_ARGS__); \
58 #define DPRINTF(format, ...) do { } while (0)
64 * | SIGNATURE | PAYLOAD |
65 * | |[ BLOBMSG CONTAINER ]|
66 * | |[[T,i,v,e,f,pubkey ]]|
74 static const struct blob_attr_info cert_policy[CERT_ATTR_MAX] = {
75 [CERT_ATTR_SIGNATURE] = { .type = BLOB_ATTR_BINARY },
76 [CERT_ATTR_PAYLOAD] = { .type = BLOB_ATTR_NESTED },
84 static const struct blobmsg_policy cert_cont_policy[CERT_CT_ATTR_MAX] = {
85 [CERT_CT_ATTR_PAYLOAD] = { .name = "ucert", .type = BLOBMSG_TYPE_TABLE },
88 enum cert_payload_attr {
89 CERT_PL_ATTR_CERTTYPE,
91 CERT_PL_ATTR_VALIDFROMTIME,
92 CERT_PL_ATTR_EXPIRETIME,
94 CERT_PL_ATTR_KEY_FINGERPRINT,
104 static const struct blobmsg_policy cert_payload_policy[CERT_PL_ATTR_MAX] = {
105 [CERT_PL_ATTR_CERTTYPE] = { .name = "certtype", .type = BLOBMSG_TYPE_INT32 },
106 [CERT_PL_ATTR_CERTID] = { .name = "certid", .type = BLOBMSG_TYPE_INT32 },
107 [CERT_PL_ATTR_VALIDFROMTIME] = { .name = "validfrom", .type = BLOBMSG_TYPE_INT64 },
108 [CERT_PL_ATTR_EXPIRETIME] = { .name = "expiresat", .type = BLOBMSG_TYPE_INT64 },
109 [CERT_PL_ATTR_PUBKEY] = { .name = "pubkey", .type = BLOBMSG_TYPE_STRING },
110 [CERT_PL_ATTR_KEY_FINGERPRINT] = { .name = "fingerprint", .type = BLOBMSG_TYPE_STRING },
113 /* list to store certificate chain at runtime */
115 struct list_head list;
116 struct blob_attr *cert[CERT_ATTR_MAX];
119 /* write buffer to file */
120 static bool write_file(const char *filename, void *buf, size_t len, bool append) {
124 f = fopen(filename, append?"a":"w");
128 outlen = fwrite(buf, 1, len, f);
130 return (outlen == len);
133 /* reads a whole file to a buffer - returns -1 on errors and sets errno */
134 static ssize_t read_file(const char *filename, void *buf, size_t len, size_t minlen) {
138 f = fopen(filename, "r");
142 ret = fread(buf, 1, len, f);
144 /* Ensure that feof() yields the correct result when the file is exactly
150 } else if (!feof(f)) {
153 } else if ((size_t)ret < minlen) {
162 /* load certfile into list */
163 static int cert_load(const char *certfile, struct list_head *chain) {
164 struct blob_attr *certtb[CERT_ATTR_MAX];
165 struct blob_attr *bufpt;
166 struct cert_object *cobj;
167 char filebuf[CERT_BUF_LEN];
168 int ret = 0, pret = 0;
172 len = read_file(certfile, filebuf, sizeof(filebuf) - 1, 0);
175 perror("Unable to load certificate file");
179 bufpt = (struct blob_attr *)filebuf;
181 pret = blob_parse_untrusted(bufpt, len, certtb, cert_policy, CERT_ATTR_MAX);
183 /* no attributes found */
186 if (pos + blob_pad_len(bufpt) > (size_t) len)
187 /* blob exceeds filebuffer */
190 pos += blob_pad_len(bufpt);
192 if (!certtb[CERT_ATTR_SIGNATURE])
193 /* no signature -> drop */
196 cobj = calloc(1, sizeof(*cobj));
197 cobj->cert[CERT_ATTR_SIGNATURE] = blob_memdup(certtb[CERT_ATTR_SIGNATURE]);
198 if (certtb[CERT_ATTR_PAYLOAD])
199 cobj->cert[CERT_ATTR_PAYLOAD] = blob_memdup(certtb[CERT_ATTR_PAYLOAD]);
201 list_add_tail(&cobj->list, chain);
203 /* repeat parsing while there is still enough remaining data in buffer */
204 } while((size_t) len > pos + sizeof(struct blob_attr) && (bufpt = blob_next(bufpt)));
210 /* append signature to certfile */
211 static int cert_append(const char *certfile, const char *sigfile) {
212 char filebuf[CERT_BUF_LEN];
213 struct blob_buf sigbuf = {0};
217 len = read_file(sigfile, filebuf, sizeof(filebuf) - 1, 64);
220 perror("Unable to load signature file");
225 blob_buf_init(&sigbuf, 0);
226 blob_put(&sigbuf, CERT_ATTR_SIGNATURE, filebuf, len);
227 ret = write_file(certfile, sigbuf.head, blob_raw_len(sigbuf.head), true);
228 blob_buf_free(&sigbuf);
233 /* verify the signature of a single chain element */
234 static int cert_verify_blob(struct blob_attr *cert[CERT_ATTR_MAX],
235 const char *pubkeyfile, const char *pubkeydir) {
237 char msgfname[256], sigfname[256];
239 char tmpdir[] = "/tmp/ucert-XXXXXX";
241 if (mkdtemp(tmpdir) == NULL)
244 snprintf(msgfname, sizeof(msgfname) - 1, "%s/%s", tmpdir, "payload");
245 snprintf(sigfname, sizeof(sigfname) - 1, "%s/%s", tmpdir, "payload.sig");
247 for (i = 0; i < CERT_ATTR_MAX; i++) {
248 struct blob_attr *v = cert[i];
253 switch(cert_policy[i].type) {
254 case BLOB_ATTR_BINARY:
255 write_file(sigfname, blob_data(v), blob_len(v), false);
257 case BLOB_ATTR_NESTED:
258 write_file(msgfname, blob_data(v), blob_len(v), false);
263 ret = usign_v(msgfname, pubkeyfile, pubkeydir, sigfname, quiet);
272 /* verify cert chain (and message) */
273 static int chain_verify(const char *msgfile, const char *pubkeyfile,
274 const char *pubkeydir, struct list_head *chain) {
275 struct cert_object *cobj;
276 struct blob_attr *containertb[CERT_CT_ATTR_MAX];
277 struct blob_attr *payloadtb[CERT_PL_ATTR_MAX];
278 char tmpdir[] = "/tmp/ucert-XXXXXX";
279 char chainedpubkey[256] = {0};
280 char chainedfp[17] = {0};
281 char extsigfile[256] = {0};
286 if (mkdtemp(tmpdir) == NULL)
292 gettimeofday(&tv, NULL);
294 list_for_each_entry(cobj, chain, list) {
295 /* blob has payload, verify that using signature */
296 if (cobj->cert[CERT_ATTR_PAYLOAD]) {
301 ret = cert_verify_blob(cobj->cert, chainedpubkey[0]?chainedpubkey:pubkeyfile, pubkeydir);
303 goto clean_and_return;
305 blobmsg_parse(cert_cont_policy,
306 ARRAY_SIZE(cert_cont_policy),
308 blob_data(cobj->cert[CERT_ATTR_PAYLOAD]),
309 blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
310 if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
312 DPRINTF("no ucert in signed payload\n");
313 goto clean_and_return;
315 blobmsg_parse(cert_payload_policy,
316 ARRAY_SIZE(cert_payload_policy),
318 blobmsg_data(containertb[CERT_CT_ATTR_PAYLOAD]),
319 blobmsg_data_len(containertb[CERT_CT_ATTR_PAYLOAD]));
321 if (!payloadtb[CERT_PL_ATTR_CERTTYPE] ||
322 !payloadtb[CERT_PL_ATTR_VALIDFROMTIME] ||
323 !payloadtb[CERT_PL_ATTR_EXPIRETIME] ||
324 !payloadtb[CERT_PL_ATTR_PUBKEY]) {
326 DPRINTF("missing mandatory ucert attributes\n");
327 goto clean_and_return;
329 certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
330 validfrom = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_VALIDFROMTIME]);
331 expiresat = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_EXPIRETIME]);
333 if (certtype != CERTTYPE_AUTH) {
335 DPRINTF("wrong certificate type\n");
336 goto clean_and_return;
339 if (tv.tv_sec < validfrom ||
340 tv.tv_sec >= expiresat) {
342 DPRINTF("certificate expired\n");
343 goto clean_and_return;
346 snprintf(chainedpubkey, sizeof(chainedpubkey) - 1, "%s/%s", tmpdir, "chained-pubkey");
347 write_file(chainedpubkey,
348 blobmsg_data(payloadtb[CERT_PL_ATTR_PUBKEY]),
349 blobmsg_data_len(payloadtb[CERT_PL_ATTR_PUBKEY]),
352 if (usign_f_pubkey(chainedfp, chainedpubkey, quiet)) {
353 DPRINTF("cannot get fingerprint for chained key\n");
355 goto clean_and_return;
357 if (pubkeydir && _usign_key_is_revoked(chainedfp, pubkeydir)) {
358 DPRINTF("key %s has been revoked!\n", chainedfp);
360 goto clean_and_return;
363 /* blob doesn't have payload, verify message using signature */
365 snprintf(extsigfile, sizeof(extsigfile) - 1, "%s/%s", tmpdir, "ext-sig");
366 write_file(extsigfile,
367 blob_data(cobj->cert[CERT_ATTR_SIGNATURE]),
368 blob_len(cobj->cert[CERT_ATTR_SIGNATURE]),
370 checkmsg = ret = usign_v(msgfile,
371 chainedpubkey[0]?chainedpubkey:pubkeyfile,
372 pubkeydir, extsigfile, quiet);
375 DPRINTF("stray trailing signature without anything to verify!\n");
382 DPRINTF("missing signature to verify message!\n");
385 if (chainedpubkey[0])
386 unlink(chainedpubkey);
388 return ret | checkmsg;
392 /* dump single chain element to console */
393 static void cert_dump_blob(struct blob_attr *cert[CERT_ATTR_MAX]) {
397 for (i = 0; i < CERT_ATTR_MAX; i++) {
398 struct blob_attr *v = cert[i];
403 switch(cert_policy[i].type) {
404 case BLOB_ATTR_BINARY:
405 printf("signature:\n---\n%s---\n", (char *) blob_data(v));
407 case BLOB_ATTR_NESTED:
408 json = blobmsg_format_json_indent(blob_data(v), false, 0);
410 DPRINTF("cannot parse payload\n");
413 printf("payload:\n---\n%s\n---\n", json);
420 /* dump certfile to console */
421 static int cert_dump(const char *certfile) {
422 struct cert_object *cobj;
423 static LIST_HEAD(certchain);
424 unsigned int count = 0;
426 if (cert_load(certfile, &certchain)) {
427 DPRINTF("cannot parse cert\n");
431 list_for_each_entry(cobj, &certchain, list) {
432 printf("=== CHAIN ELEMENT %02u ===\n", ++count);
433 cert_dump_blob(cobj->cert);
439 /* issue an auth certificate for pubkey */
440 static int cert_issue(const char *certfile, const char *pubkeyfile, const char *seckeyfile) {
441 struct blob_buf payloadbuf = {0};
442 struct blob_buf certbuf = {0};
444 ssize_t pklen, siglen;
449 char fname[256], sfname[256];
451 char tmpdir[] = "/tmp/ucert-XXXXXX";
453 pklen = read_file(pubkeyfile, pkb, sizeof(pkb) - 1, 32);
456 perror("Unable to load public key file");
463 if (usign_f_pubkey(pkfp, pubkeyfile, quiet))
466 gettimeofday(&tv, NULL);
468 if (mkdtemp(tmpdir) == NULL)
471 while (revoker >= 0) {
472 blob_buf_init(&payloadbuf, 0);
473 c = blobmsg_open_table(&payloadbuf, "ucert");
474 blobmsg_add_u32(&payloadbuf, "certtype", revoker?CERTTYPE_REVOKE:CERTTYPE_AUTH);
475 blobmsg_add_u64(&payloadbuf, "validfrom", tv.tv_sec);
477 blobmsg_add_u64(&payloadbuf, "expiresat", tv.tv_sec + 60 * 60 * 24 * 365);
478 blobmsg_add_string(&payloadbuf, "pubkey", pkb);
480 blobmsg_add_string(&payloadbuf, "fingerprint", pkfp);
483 blobmsg_close_table(&payloadbuf, c);
485 snprintf(fname, sizeof(fname) - 1, "%s/%s", tmpdir, revoker?"revoker":"payload");
486 write_file(fname, blob_data(payloadbuf.head), blob_len(payloadbuf.head), false);
488 snprintf(sfname, sizeof(sfname) - 1, "%s/%s", tmpdir, revoker?"revoker.sig":"payload.sig");
489 if (usign_s(fname, seckeyfile, sfname, quiet))
492 siglen = read_file(sfname, sigb, sizeof(sigb) - 1, 1);
495 perror("Unable to load signature file");
505 blob_buf_init(&certbuf, 0);
506 blob_put(&certbuf, CERT_ATTR_SIGNATURE, sigb, siglen);
507 blob_put(&certbuf, CERT_ATTR_PAYLOAD, blob_data(payloadbuf.head), blob_len(payloadbuf.head));
508 snprintf(fname, sizeof(fname) - 1, "%s%s", certfile, revoker?".revoke":"");
509 write_file(fname, certbuf.head, blob_raw_len(certbuf.head), true);
510 blob_buf_free(&certbuf);
511 blob_buf_free(&payloadbuf);
522 /* process revoker certificate */
523 static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
524 static LIST_HEAD(certchain);
525 struct cert_object *cobj;
526 struct blob_attr *containertb[CERT_CT_ATTR_MAX];
527 struct blob_attr *payloadtb[CERT_PL_ATTR_MAX];
531 enum certtype_id certtype;
537 if (cert_load(certfile, &certchain)) {
538 DPRINTF("cannot parse cert\n");
542 gettimeofday(&tv, NULL);
544 list_for_each_entry(cobj, &certchain, list) {
545 if (!cobj->cert[CERT_ATTR_PAYLOAD])
548 /* blob has payload, verify that using signature */
549 ret = cert_verify_blob(cobj->cert, NULL, pubkeydir);
553 blobmsg_parse(cert_cont_policy,
554 ARRAY_SIZE(cert_cont_policy),
556 blob_data(cobj->cert[CERT_ATTR_PAYLOAD]),
557 blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
558 if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
559 DPRINTF("no ucert in signed payload\n");
563 blobmsg_parse(cert_payload_policy,
564 ARRAY_SIZE(cert_payload_policy),
566 blobmsg_data(containertb[CERT_CT_ATTR_PAYLOAD]),
567 blobmsg_data_len(containertb[CERT_CT_ATTR_PAYLOAD]));
569 if (!payloadtb[CERT_PL_ATTR_CERTTYPE] ||
570 !payloadtb[CERT_PL_ATTR_VALIDFROMTIME] ||
571 !payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]) {
572 DPRINTF("missing mandatory ucert attributes\n");
576 certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
577 validfrom = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_VALIDFROMTIME]);
578 fingerprint = blobmsg_get_string(payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]);
580 if (certtype != CERTTYPE_REVOKE) {
581 DPRINTF("wrong certificate type\n");
585 if (tv.tv_sec < validfrom) {
589 snprintf(rfname, sizeof(rfname)-1, "%s/%s", pubkeydir, fingerprint);
590 /* check if entry in pubkeydir exists */
591 if (stat(rfname, &st) == 0) {
592 if (_usign_key_is_revoked(fingerprint, pubkeydir)) {
593 DPRINTF("existing revoker deadlink for key %s\n", fingerprint);
597 /* remove any other entry */
602 ret = symlink(".revoked.", rfname);
606 DPRINTF("created revoker deadlink for key %s\n", fingerprint);
612 /* load and verify certfile (and message) */
613 static int cert_verify(const char *certfile, const char *pubkeyfile, const char *pubkeydir, const char *msgfile) {
614 static LIST_HEAD(certchain);
616 if (cert_load(certfile, &certchain)) {
617 DPRINTF("cannot parse cert\n");
621 return chain_verify(msgfile, pubkeyfile, pubkeydir, &certchain);
625 static int usage(const char *cmd)
627 #ifndef UCERT_STRIP_MESSAGES
629 "Usage: %s <command> <options>\n"
632 " -A: append signature (needs -c and -x)\n"
633 " -D: dump (needs -c)\n"
634 " -I: issue cert and revoker (needs -c and -p and -s)\n"
635 #endif /* UCERT_FULL */
636 " -R: process revoker certificate (needs -c and -P)\n"
637 " -V: verify (needs -c and -p|-P, may have -m)\n"
639 " -c <file>: certificate file\n"
640 " -m <file>: message file (verify only)\n"
641 " -p <file>: public key file\n"
642 " -P <path>: public key directory (verify only)\n"
643 " -q: quiet (do not print verification result, use return code only)\n"
645 " -s <file>: secret key file (issue only)\n"
646 " -x <file>: signature file (append only)\n"
647 #endif /* UCERT_FULL */
650 #endif /* UCERT_STRIP_MESSAGES */
654 /* parse command line options and call functions */
655 int main(int argc, char *argv[]) {
657 const char *msgfile = NULL;
658 const char *pubkeyfile = NULL;
659 const char *pubkeydir = NULL;
660 const char *certfile = NULL;
662 const char *sigfile = NULL;
663 const char *seckeyfile = NULL;
667 while ((ch = getopt(argc, argv,
677 return usage(argv[0]);
682 return usage(argv[0]);
687 return usage(argv[0]);
693 return usage(argv[0]);
698 return usage(argv[0]);
702 if (certfile || cmd == CMD_NONE)
703 return usage(argv[0]);
707 if (msgfile || cmd != CMD_VERIFY)
708 return usage(argv[0]);
712 if (pubkeyfile || (cmd != CMD_VERIFY && cmd != CMD_ISSUE) || cmd == CMD_NONE)
713 return usage(argv[0]);
717 if (pubkeydir || (cmd != CMD_VERIFY && cmd != CMD_REVOKE) || cmd == CMD_NONE)
718 return usage(argv[0]);
723 return usage(argv[0]);
728 if (seckeyfile || cmd != CMD_ISSUE || cmd == CMD_NONE)
729 return usage(argv[0]);
733 if (sigfile || cmd != CMD_APPEND || cmd == CMD_NONE)
734 return usage(argv[0]);
739 return usage(argv[0]);
746 if (certfile && sigfile)
747 return cert_append(certfile, sigfile);
749 return usage(argv[0]);
752 return cert_dump(certfile);
754 return usage(argv[0]);
756 if (certfile && pubkeyfile && seckeyfile)
757 return cert_issue(certfile, pubkeyfile, seckeyfile);
759 return usage(argv[0]);
762 if (certfile && pubkeydir)
763 return cert_process_revoker(certfile, pubkeydir);
765 return usage(argv[0]);
767 if (certfile && (pubkeyfile || pubkeydir))
768 return cert_verify(certfile, pubkeyfile, pubkeydir, msgfile);
770 return usage(argv[0]);
772 return usage(argv[0]);
776 return usage(argv[0]);