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/*
* Based on certificate dump functionality from ucert.c:
*
* Copyright (C) 2018 Daniel Golle <daniel@makrotopia.org>
* SPDX-License-Identifier: GPL-3.0
*
*/
#include <stdio.h>
#include <stdint.h>
#include <stddef.h>
#include <libgen.h>
#include "blob.h"
#include "list.h"
#include "blobmsg_json.h"
#define CERT_BUF_LEN 4096
/*
* ucert structure
* | BLOB |
* | SIGNATURE | PAYLOAD |
* | |[ BLOBMSG CONTAINER ]|
* | |[[T,i,v,e,f,pubkey ]]|
*/
enum cert_attr {
CERT_ATTR_SIGNATURE,
CERT_ATTR_PAYLOAD,
CERT_ATTR_MAX
};
static const struct blob_attr_info cert_policy[CERT_ATTR_MAX] = {
[CERT_ATTR_SIGNATURE] = { .type = BLOB_ATTR_BINARY },
[CERT_ATTR_PAYLOAD] = { .type = BLOB_ATTR_NESTED },
};
enum cert_cont_attr {
CERT_CT_ATTR_PAYLOAD,
CERT_CT_ATTR_MAX
};
enum cert_payload_attr {
CERT_PL_ATTR_CERTTYPE,
CERT_PL_ATTR_CERTID,
CERT_PL_ATTR_VALIDFROMTIME,
CERT_PL_ATTR_EXPIRETIME,
CERT_PL_ATTR_PUBKEY,
CERT_PL_ATTR_KEY_FINGERPRINT,
CERT_PL_ATTR_MAX
};
enum certtype_id {
CERTTYPE_UNSPEC,
CERTTYPE_AUTH,
CERTTYPE_REVOKE
};
/* list to store certificate chain at runtime */
struct cert_object {
struct list_head list;
struct blob_attr *cert[CERT_ATTR_MAX];
};
static int cert_load(const char *certfile, struct list_head *chain)
{
FILE *f;
struct blob_attr *certtb[CERT_ATTR_MAX];
struct blob_attr *bufpt;
struct cert_object *cobj;
char *filebuf = NULL;
int ret = 0, pret = 0;
size_t len, pos = 0;
f = fopen(certfile, "r");
if (!f)
return 1;
filebuf = malloc(CERT_BUF_LEN+1);
if (!filebuf)
return 1;
len = fread(filebuf, 1, CERT_BUF_LEN, f);
if (len < 64) {
free(filebuf);
return 1;
}
ret = ferror(f) || !feof(f);
fclose(f);
if (ret) {
free(filebuf);
return 1;
}
bufpt = (struct blob_attr *)filebuf;
do {
pret = blob_parse_untrusted(bufpt, len, certtb, cert_policy, CERT_ATTR_MAX);
if (pret <= 0)
/* no attributes found */
break;
if (pos + blob_pad_len(bufpt) > len)
/* blob exceeds filebuffer */
break;
else
pos += blob_pad_len(bufpt);
if (!certtb[CERT_ATTR_SIGNATURE])
/* no signature -> drop */
break;
cobj = calloc(1, sizeof(*cobj));
cobj->cert[CERT_ATTR_SIGNATURE] = blob_memdup(certtb[CERT_ATTR_SIGNATURE]);
if (certtb[CERT_ATTR_PAYLOAD])
cobj->cert[CERT_ATTR_PAYLOAD] = blob_memdup(certtb[CERT_ATTR_PAYLOAD]);
list_add_tail(&cobj->list, chain);
ret += pret;
/* repeat parsing while there is still enough remaining data in buffer */
} while(len > pos + sizeof(struct blob_attr) && (bufpt = blob_next(bufpt)));
free(filebuf);
return (ret <= 0);
}
/* dump single chain element to console */
static void cert_dump_blob(struct blob_attr *cert[CERT_ATTR_MAX])
{
int i;
char *json = NULL;
for (i = 0; i < CERT_ATTR_MAX; i++) {
struct blob_attr *v = cert[i];
if (!v)
continue;
switch(cert_policy[i].type) {
case BLOB_ATTR_BINARY:
fprintf(stdout, "signature:\n---\n%s---\n", (char *) blob_data(v));
break;
case BLOB_ATTR_NESTED:
json = blobmsg_format_json_indent(blob_data(v), false, 0);
if (!json)
continue;
fprintf(stdout, "payload:\n---\n%s\n---\n", json);
free(json);
break;
}
}
}
static int cert_dump(const char *certfile)
{
struct cert_object *cobj;
static LIST_HEAD(certchain);
unsigned int count = 0;
if (cert_load(certfile, &certchain)) {
fprintf(stderr, "cannot parse cert %s\n", basename((char *) certfile));
return 1;
}
list_for_each_entry(cobj, &certchain, list) {
fprintf(stdout, "=== CHAIN ELEMENT %02u ===\n", ++count);
cert_dump_blob(cobj->cert);
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc != 2) {
fprintf(stderr, "Usage: %s <cert.ucert>\n", argv[0]);
return 3;
}
cert_dump(argv[1]);
return 0;
}
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