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: " format, __func__, ## __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], *end;
171 len = read_file(certfile, filebuf, sizeof(filebuf) - 1, 0);
174 perror("Unable to load certificate file");
178 bufpt = (struct blob_attr *)filebuf;
182 len = end - (char *)bufpt;
186 if (blob_parse_untrusted(bufpt, len, certtb, cert_policy, CERT_ATTR_MAX) <= 0)
187 /* no attributes found */
190 if (!certtb[CERT_ATTR_SIGNATURE])
191 /* no signature -> drop */
194 cobj = calloc(1, sizeof(*cobj));
195 cobj->cert[CERT_ATTR_SIGNATURE] = blob_memdup(certtb[CERT_ATTR_SIGNATURE]);
196 if (certtb[CERT_ATTR_PAYLOAD])
197 cobj->cert[CERT_ATTR_PAYLOAD] = blob_memdup(certtb[CERT_ATTR_PAYLOAD]);
199 list_add_tail(&cobj->list, chain);
202 /* Repeat parsing while there is still enough remaining data in buffer
204 * Note that blob_next() is only valid for untrusted data because blob_parse_untrusted()
205 * verified that the buffer contains at least one blob, and that it is completely contained
207 bufpt = blob_next(bufpt);
214 /* append signature to certfile */
215 static int cert_append(const char *certfile, const char *sigfile) {
216 char filebuf[CERT_BUF_LEN];
217 struct blob_buf sigbuf = {0};
221 len = read_file(sigfile, filebuf, sizeof(filebuf) - 1, 64);
224 perror("Unable to load signature file");
229 blob_buf_init(&sigbuf, 0);
230 blob_put(&sigbuf, CERT_ATTR_SIGNATURE, filebuf, len);
231 ret = write_file(certfile, sigbuf.head, blob_raw_len(sigbuf.head), true);
232 blob_buf_free(&sigbuf);
237 /* verify the signature of a single chain element */
238 static int cert_verify_blob(struct blob_attr *cert[CERT_ATTR_MAX],
239 const char *pubkeyfile, const char *pubkeydir) {
241 char msgfname[256], sigfname[256];
243 char tmpdir[] = "/tmp/ucert-XXXXXX";
245 if (mkdtemp(tmpdir) == NULL)
248 snprintf(msgfname, sizeof(msgfname) - 1, "%s/%s", tmpdir, "payload");
249 snprintf(sigfname, sizeof(sigfname) - 1, "%s/%s", tmpdir, "payload.sig");
251 for (i = 0; i < CERT_ATTR_MAX; i++) {
252 struct blob_attr *v = cert[i];
257 switch(cert_policy[i].type) {
258 case BLOB_ATTR_BINARY:
259 write_file(sigfname, blob_data(v), blob_len(v), false);
261 case BLOB_ATTR_NESTED:
262 write_file(msgfname, blob_data(v), blob_len(v), false);
267 ret = usign_v(msgfname, pubkeyfile, pubkeydir, sigfname, quiet);
276 /* verify cert chain (and message) */
277 static int chain_verify(const char *msgfile, const char *pubkeyfile,
278 const char *pubkeydir, struct list_head *chain) {
279 struct cert_object *cobj;
280 struct blob_attr *containertb[CERT_CT_ATTR_MAX];
281 struct blob_attr *payloadtb[CERT_PL_ATTR_MAX];
282 char tmpdir[] = "/tmp/ucert-XXXXXX";
283 char chainedpubkey[256] = {0};
284 char chainedfp[17] = {0};
285 char extsigfile[256] = {0};
290 if (mkdtemp(tmpdir) == NULL)
296 gettimeofday(&tv, NULL);
298 list_for_each_entry(cobj, chain, list) {
299 /* blob has payload, verify that using signature */
300 if (cobj->cert[CERT_ATTR_PAYLOAD]) {
305 ret = cert_verify_blob(cobj->cert, chainedpubkey[0]?chainedpubkey:pubkeyfile, pubkeydir);
307 goto clean_and_return;
309 blobmsg_parse(cert_cont_policy,
310 ARRAY_SIZE(cert_cont_policy),
312 blob_data(cobj->cert[CERT_ATTR_PAYLOAD]),
313 blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
314 if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
316 DPRINTF("no ucert in signed payload\n");
317 goto clean_and_return;
319 blobmsg_parse(cert_payload_policy,
320 ARRAY_SIZE(cert_payload_policy),
322 blobmsg_data(containertb[CERT_CT_ATTR_PAYLOAD]),
323 blobmsg_data_len(containertb[CERT_CT_ATTR_PAYLOAD]));
325 if (!payloadtb[CERT_PL_ATTR_CERTTYPE] ||
326 !payloadtb[CERT_PL_ATTR_VALIDFROMTIME] ||
327 !payloadtb[CERT_PL_ATTR_EXPIRETIME] ||
328 !payloadtb[CERT_PL_ATTR_PUBKEY]) {
330 DPRINTF("missing mandatory ucert attributes\n");
331 goto clean_and_return;
333 certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
334 validfrom = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_VALIDFROMTIME]);
335 expiresat = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_EXPIRETIME]);
337 if (certtype != CERTTYPE_AUTH) {
339 DPRINTF("wrong certificate type\n");
340 goto clean_and_return;
343 if (tv.tv_sec < validfrom ||
344 tv.tv_sec >= expiresat) {
346 DPRINTF("certificate expired\n");
347 goto clean_and_return;
350 snprintf(chainedpubkey, sizeof(chainedpubkey) - 1, "%s/%s", tmpdir, "chained-pubkey");
351 write_file(chainedpubkey,
352 blobmsg_data(payloadtb[CERT_PL_ATTR_PUBKEY]),
353 blobmsg_data_len(payloadtb[CERT_PL_ATTR_PUBKEY]),
356 if (usign_f_pubkey(chainedfp, chainedpubkey, quiet)) {
357 DPRINTF("cannot get fingerprint for chained key\n");
359 goto clean_and_return;
361 if (pubkeydir && _usign_key_is_revoked(chainedfp, pubkeydir)) {
362 DPRINTF("key %s has been revoked!\n", chainedfp);
364 goto clean_and_return;
367 /* blob doesn't have payload, verify message using signature */
369 snprintf(extsigfile, sizeof(extsigfile) - 1, "%s/%s", tmpdir, "ext-sig");
370 write_file(extsigfile,
371 blob_data(cobj->cert[CERT_ATTR_SIGNATURE]),
372 blob_len(cobj->cert[CERT_ATTR_SIGNATURE]),
374 checkmsg = ret = usign_v(msgfile,
375 chainedpubkey[0]?chainedpubkey:pubkeyfile,
376 pubkeydir, extsigfile, quiet);
379 DPRINTF("stray trailing signature without anything to verify!\n");
386 DPRINTF("missing signature to verify message!\n");
389 if (chainedpubkey[0])
390 unlink(chainedpubkey);
392 return ret | checkmsg;
396 /* dump single chain element to console */
397 static void cert_dump_blob(struct blob_attr *cert[CERT_ATTR_MAX]) {
401 for (i = 0; i < CERT_ATTR_MAX; i++) {
402 struct blob_attr *v = cert[i];
407 switch(cert_policy[i].type) {
408 case BLOB_ATTR_BINARY:
409 printf("signature:\n---\n%s---\n", (char *) blob_data(v));
411 case BLOB_ATTR_NESTED:
412 json = blobmsg_format_json_indent(blob_data(v), false, 0);
414 DPRINTF("cannot parse payload\n");
417 printf("payload:\n---\n%s\n---\n", json);
424 /* dump certfile to console */
425 static int cert_dump(const char *certfile) {
426 struct cert_object *cobj;
427 static LIST_HEAD(certchain);
428 unsigned int count = 0;
430 if (cert_load(certfile, &certchain)) {
431 DPRINTF("cannot parse cert\n");
435 list_for_each_entry(cobj, &certchain, list) {
436 printf("=== CHAIN ELEMENT %02u ===\n", ++count);
437 cert_dump_blob(cobj->cert);
443 /* issue an auth certificate for pubkey */
444 static int cert_issue(const char *certfile, const char *pubkeyfile, const char *seckeyfile) {
445 struct blob_buf payloadbuf = {0};
446 struct blob_buf certbuf = {0};
448 ssize_t pklen, siglen;
453 char fname[256], sfname[256];
455 char tmpdir[] = "/tmp/ucert-XXXXXX";
457 pklen = read_file(pubkeyfile, pkb, sizeof(pkb) - 1, 32);
460 perror("Unable to load public key file");
467 if (usign_f_pubkey(pkfp, pubkeyfile, quiet))
470 gettimeofday(&tv, NULL);
472 if (mkdtemp(tmpdir) == NULL)
475 while (revoker >= 0) {
476 blob_buf_init(&payloadbuf, 0);
477 c = blobmsg_open_table(&payloadbuf, "ucert");
478 blobmsg_add_u32(&payloadbuf, "certtype", revoker?CERTTYPE_REVOKE:CERTTYPE_AUTH);
479 blobmsg_add_u64(&payloadbuf, "validfrom", tv.tv_sec);
481 blobmsg_add_u64(&payloadbuf, "expiresat", tv.tv_sec + 60 * 60 * 24 * 365);
482 blobmsg_add_string(&payloadbuf, "pubkey", pkb);
484 blobmsg_add_string(&payloadbuf, "fingerprint", pkfp);
487 blobmsg_close_table(&payloadbuf, c);
489 snprintf(fname, sizeof(fname) - 1, "%s/%s", tmpdir, revoker?"revoker":"payload");
490 write_file(fname, blob_data(payloadbuf.head), blob_len(payloadbuf.head), false);
492 snprintf(sfname, sizeof(sfname) - 1, "%s/%s", tmpdir, revoker?"revoker.sig":"payload.sig");
493 if (usign_s(fname, seckeyfile, sfname, quiet))
496 siglen = read_file(sfname, sigb, sizeof(sigb) - 1, 1);
499 perror("Unable to load signature file");
509 blob_buf_init(&certbuf, 0);
510 blob_put(&certbuf, CERT_ATTR_SIGNATURE, sigb, siglen);
511 blob_put(&certbuf, CERT_ATTR_PAYLOAD, blob_data(payloadbuf.head), blob_len(payloadbuf.head));
512 snprintf(fname, sizeof(fname) - 1, "%s%s", certfile, revoker?".revoke":"");
513 write_file(fname, certbuf.head, blob_raw_len(certbuf.head), true);
514 blob_buf_free(&certbuf);
515 blob_buf_free(&payloadbuf);
526 /* process revoker certificate */
527 static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
528 static LIST_HEAD(certchain);
529 struct cert_object *cobj;
530 struct blob_attr *containertb[CERT_CT_ATTR_MAX];
531 struct blob_attr *payloadtb[CERT_PL_ATTR_MAX];
535 enum certtype_id certtype;
541 if (cert_load(certfile, &certchain)) {
542 DPRINTF("cannot parse cert\n");
546 gettimeofday(&tv, NULL);
548 list_for_each_entry(cobj, &certchain, list) {
549 if (!cobj->cert[CERT_ATTR_PAYLOAD])
552 /* blob has payload, verify that using signature */
553 ret = cert_verify_blob(cobj->cert, NULL, pubkeydir);
557 blobmsg_parse(cert_cont_policy,
558 ARRAY_SIZE(cert_cont_policy),
560 blob_data(cobj->cert[CERT_ATTR_PAYLOAD]),
561 blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
562 if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
563 DPRINTF("no ucert in signed payload\n");
567 blobmsg_parse(cert_payload_policy,
568 ARRAY_SIZE(cert_payload_policy),
570 blobmsg_data(containertb[CERT_CT_ATTR_PAYLOAD]),
571 blobmsg_data_len(containertb[CERT_CT_ATTR_PAYLOAD]));
573 if (!payloadtb[CERT_PL_ATTR_CERTTYPE] ||
574 !payloadtb[CERT_PL_ATTR_VALIDFROMTIME] ||
575 !payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]) {
576 DPRINTF("missing mandatory ucert attributes\n");
580 certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
581 validfrom = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_VALIDFROMTIME]);
582 fingerprint = blobmsg_get_string(payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]);
584 if (certtype != CERTTYPE_REVOKE) {
585 DPRINTF("wrong certificate type\n");
589 if (tv.tv_sec < validfrom) {
593 snprintf(rfname, sizeof(rfname)-1, "%s/%s", pubkeydir, fingerprint);
594 /* check if entry in pubkeydir exists */
595 if (stat(rfname, &st) == 0) {
596 if (_usign_key_is_revoked(fingerprint, pubkeydir)) {
597 DPRINTF("existing revoker deadlink for key %s\n", fingerprint);
601 /* remove any other entry */
606 ret = symlink(".revoked.", rfname);
610 DPRINTF("created revoker deadlink for key %s\n", fingerprint);
616 /* load and verify certfile (and message) */
617 static int cert_verify(const char *certfile, const char *pubkeyfile, const char *pubkeydir, const char *msgfile) {
618 static LIST_HEAD(certchain);
620 if (cert_load(certfile, &certchain)) {
621 DPRINTF("cannot parse cert\n");
625 return chain_verify(msgfile, pubkeyfile, pubkeydir, &certchain);
629 static int usage(const char *cmd)
631 #ifndef UCERT_STRIP_MESSAGES
633 "Usage: %s <command> <options>\n"
636 " -A: append signature (needs -c and -x)\n"
637 " -D: dump (needs -c)\n"
638 " -I: issue cert and revoker (needs -c and -p and -s)\n"
639 #endif /* UCERT_FULL */
640 " -R: process revoker certificate (needs -c and -P)\n"
641 " -V: verify (needs -c and -p|-P, may have -m)\n"
643 " -c <file>: certificate file\n"
644 " -m <file>: message file (verify only)\n"
645 " -p <file>: public key file\n"
646 " -P <path>: public key directory (verify only)\n"
647 " -q: quiet (do not print verification result, use return code only)\n"
649 " -s <file>: secret key file (issue only)\n"
650 " -x <file>: signature file (append only)\n"
651 #endif /* UCERT_FULL */
654 #endif /* UCERT_STRIP_MESSAGES */
658 /* parse command line options and call functions */
659 int main(int argc, char *argv[]) {
661 const char *msgfile = NULL;
662 const char *pubkeyfile = NULL;
663 const char *pubkeydir = NULL;
664 const char *certfile = NULL;
666 const char *sigfile = NULL;
667 const char *seckeyfile = NULL;
671 while ((ch = getopt(argc, argv,
681 return usage(argv[0]);
686 return usage(argv[0]);
691 return usage(argv[0]);
697 return usage(argv[0]);
702 return usage(argv[0]);
706 if (certfile || cmd == CMD_NONE)
707 return usage(argv[0]);
711 if (msgfile || cmd != CMD_VERIFY)
712 return usage(argv[0]);
716 if (pubkeyfile || (cmd != CMD_VERIFY && cmd != CMD_ISSUE) || cmd == CMD_NONE)
717 return usage(argv[0]);
721 if (pubkeydir || (cmd != CMD_VERIFY && cmd != CMD_REVOKE) || cmd == CMD_NONE)
722 return usage(argv[0]);
727 return usage(argv[0]);
732 if (seckeyfile || cmd != CMD_ISSUE || cmd == CMD_NONE)
733 return usage(argv[0]);
737 if (sigfile || cmd != CMD_APPEND || cmd == CMD_NONE)
738 return usage(argv[0]);
743 return usage(argv[0]);
750 if (certfile && sigfile)
751 return cert_append(certfile, sigfile);
753 return usage(argv[0]);
756 return cert_dump(certfile);
758 return usage(argv[0]);
760 if (certfile && pubkeyfile && seckeyfile)
761 return cert_issue(certfile, pubkeyfile, seckeyfile);
763 return usage(argv[0]);
766 if (certfile && pubkeydir)
767 return cert_process_revoker(certfile, pubkeydir);
769 return usage(argv[0]);
771 if (certfile && (pubkeyfile || pubkeydir))
772 return cert_verify(certfile, pubkeyfile, pubkeydir, msgfile);
774 return usage(argv[0]);
776 return usage(argv[0]);
780 return usage(argv[0]);