// The functions here are derrived from BearSSL/tools/*.c
// When that is refactored suitably we can use them directly.
/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define NEED_BRSSL_H
#include "libsecureboot-priv.h"
#include <brssl.h>
static int
is_ign(int c)
{
if (c == 0) {
return (0);
}
if (c <= 32 || c == '-' || c == '_' || c == '.'
|| c == '/' || c == '+' || c == ':')
{
return (1);
}
return (0);
}
/*
* Get next non-ignored character, normalised:
* ASCII letters are converted to lowercase
* control characters, space, '-', '_', '.', '/', '+' and ':' are ignored
* A terminating zero is returned as 0.
*/
static int
next_char(const char **ps, const char *limit)
{
for (;;) {
int c;
if (*ps == limit) {
return (0);
}
c = *(*ps) ++;
if (c == 0) {
return (0);
}
if (c >= 'A' && c <= 'Z') {
c += 'a' - 'A';
}
if (!is_ign(c)) {
return (c);
}
}
}
/*
* Partial string equality comparison, with normalisation.
*/
static int
eqstr_chunk(const char *s1, size_t s1_len, const char *s2, size_t s2_len)
{
const char *lim1, *lim2;
lim1 = s1 + s1_len;
lim2 = s2 + s2_len;
for (;;) {
int c1, c2;
c1 = next_char(&s1, lim1);
c2 = next_char(&s2, lim2);
if (c1 != c2) {
return (0);
}
if (c1 == 0) {
return (1);
}
}
}
/* see brssl.h */
int
eqstr(const char *s1, const char *s2)
{
return (eqstr_chunk(s1, strlen(s1), s2, strlen(s2)));
}
int
looks_like_DER(const unsigned char *buf, size_t len)
{
int fb;
size_t dlen;
if (len < 2) {
return (0);
}
if (*buf ++ != 0x30) {
return (0);
}
fb = *buf ++;
len -= 2;
if (fb < 0x80) {
return ((size_t)fb == len);
} else if (fb == 0x80) {
return (0);
} else {
fb -= 0x80;
if (len < (size_t)fb + 2) {
return (0);
}
len -= (size_t)fb;
dlen = 0;
while (fb -- > 0) {
if (dlen > (len >> 8)) {
return (0);
}
dlen = (dlen << 8) + (size_t)*buf ++;
}
return (dlen == len);
}
}
static void
vblob_append(void *cc, const void *data, size_t len)
{
bvector *bv;
bv = cc;
VEC_ADDMANY(*bv, data, len);
}
void
free_pem_object_contents(pem_object *po)
{
if (po != NULL) {
xfree(po->name);
xfree(po->data);
}
}
pem_object *
decode_pem(const void *src, size_t len, size_t *num)
{
VECTOR(pem_object) pem_list = VEC_INIT;
br_pem_decoder_context pc;
pem_object po, *pos;
const unsigned char *buf;
bvector bv = VEC_INIT;
int inobj;
int extra_nl;
*num = 0;
br_pem_decoder_init(&pc);
buf = src;
inobj = 0;
po.name = NULL;
po.data = NULL;
po.data_len = 0;
extra_nl = 1;
while (len > 0) {
size_t tlen;
tlen = br_pem_decoder_push(&pc, buf, len);
buf += tlen;
len -= tlen;
switch (br_pem_decoder_event(&pc)) {
case BR_PEM_BEGIN_OBJ:
po.name = xstrdup(br_pem_decoder_name(&pc));
br_pem_decoder_setdest(&pc, vblob_append, &bv);
inobj = 1;
break;
case BR_PEM_END_OBJ:
if (inobj) {
po.data = VEC_TOARRAY(bv);
po.data_len = VEC_LEN(bv);
VEC_ADD(pem_list, po);
VEC_CLEAR(bv);
po.name = NULL;
po.data = NULL;
po.data_len = 0;
inobj = 0;
}
break;
case BR_PEM_ERROR:
xfree(po.name);
VEC_CLEAR(bv);
ve_error_set("ERROR: invalid PEM encoding");
VEC_CLEAREXT(pem_list, &free_pem_object_contents);
return (NULL);
}
/*
* We add an extra newline at the end, in order to
* support PEM files that lack the newline on their last
* line (this is somwehat invalid, but PEM format is not
* standardised and such files do exist in the wild, so
* we'd better accept them).
*/
if (len == 0 && extra_nl) {
extra_nl = 0;
buf = (const unsigned char *)"\n";
len = 1;
}
}
if (inobj) {
ve_error_set("ERROR: unfinished PEM object");
xfree(po.name);
VEC_CLEAR(bv);
VEC_CLEAREXT(pem_list, &free_pem_object_contents);
return (NULL);
}
*num = VEC_LEN(pem_list);
VEC_ADD(pem_list, po);
pos = VEC_TOARRAY(pem_list);
VEC_CLEAR(pem_list);
return (pos);
}
br_x509_certificate *
parse_certificates(unsigned char *buf, size_t len, size_t *num)
{
VECTOR(br_x509_certificate) cert_list = VEC_INIT;
pem_object *pos;
size_t u, num_pos;
br_x509_certificate *xcs;
br_x509_certificate dummy;
*num = 0;
/*
* Check for a DER-encoded certificate.
*/
if (looks_like_DER(buf, len)) {
xcs = xmalloc(2 * sizeof *xcs);
xcs[0].data = buf;
xcs[0].data_len = len;
xcs[1].data = NULL;
xcs[1].data_len = 0;
*num = 1;
return (xcs);
}
pos = decode_pem(buf, len, &num_pos);
if (pos == NULL) {
return (NULL);
}
for (u = 0; u < num_pos; u ++) {
if (eqstr(pos[u].name, "CERTIFICATE")
|| eqstr(pos[u].name, "X509 CERTIFICATE"))
{
br_x509_certificate xc;
xc.data = pos[u].data;
xc.data_len = pos[u].data_len;
pos[u].data = NULL;
VEC_ADD(cert_list, xc);
}
}
for (u = 0; u < num_pos; u ++) {
free_pem_object_contents(&pos[u]);
}
xfree(pos);
if (VEC_LEN(cert_list) == 0) {
return (NULL);
}
*num = VEC_LEN(cert_list);
dummy.data = NULL;
dummy.data_len = 0;
VEC_ADD(cert_list, dummy);
xcs = VEC_TOARRAY(cert_list);
VEC_CLEAR(cert_list);
return (xcs);
}
br_x509_certificate *
read_certificates(const char *fname, size_t *num)
{
br_x509_certificate *xcs;
unsigned char *buf;
size_t len;
*num = 0;
/*
* TODO: reading the whole file is crude; we could parse them
* in a streamed fashion. But it does not matter much in practice.
*/
buf = read_file(fname, &len);
if (buf == NULL) {
return (NULL);
}
xcs = parse_certificates(buf, len, num);
if (xcs == NULL) {
ve_error_set("ERROR: no certificate in file '%s'\n", fname);
}
xfree(buf);
return (xcs);
}
/* see brssl.h */
void
free_certificates(br_x509_certificate *certs, size_t num)
{
size_t u;
for (u = 0; u < num; u ++) {
xfree(certs[u].data);
}
xfree(certs);
}
static void
dn_append(void *ctx, const void *buf, size_t len)
{
VEC_ADDMANY(*(bvector *)ctx, buf, len);
}
int
certificate_to_trust_anchor_inner(br_x509_trust_anchor *ta,
br_x509_certificate *xc)
{
br_x509_decoder_context dc;
bvector vdn = VEC_INIT;
br_x509_pkey *pk;
br_x509_decoder_init(&dc, dn_append, &vdn);
br_x509_decoder_push(&dc, xc->data, xc->data_len);
pk = br_x509_decoder_get_pkey(&dc);
if (pk == NULL) {
ve_error_set("ERROR: CA decoding failed with error %d\n",
br_x509_decoder_last_error(&dc));
VEC_CLEAR(vdn);
return (-1);
}
ta->dn.data = VEC_TOARRAY(vdn);
ta->dn.len = VEC_LEN(vdn);
VEC_CLEAR(vdn);
ta->flags = 0;
if (br_x509_decoder_isCA(&dc)) {
ta->flags |= BR_X509_TA_CA;
}
switch (pk->key_type) {
case BR_KEYTYPE_RSA:
ta->pkey.key_type = BR_KEYTYPE_RSA;
ta->pkey.key.rsa.n = xblobdup(pk->key.rsa.n, pk->key.rsa.nlen);
ta->pkey.key.rsa.nlen = pk->key.rsa.nlen;
ta->pkey.key.rsa.e = xblobdup(pk->key.rsa.e, pk->key.rsa.elen);
ta->pkey.key.rsa.elen = pk->key.rsa.elen;
break;
case BR_KEYTYPE_EC:
ta->pkey.key_type = BR_KEYTYPE_EC;
ta->pkey.key.ec.curve = pk->key.ec.curve;
ta->pkey.key.ec.q = xblobdup(pk->key.ec.q, pk->key.ec.qlen);
ta->pkey.key.ec.qlen = pk->key.ec.qlen;
break;
default:
ve_error_set("ERROR: unsupported public key type in CA\n");
xfree(ta->dn.data);
return (-1);
}
return (0);
}
/* see brssl.h */
void
free_ta_contents(br_x509_trust_anchor *ta)
{
xfree(ta->dn.data);
switch (ta->pkey.key_type) {
case BR_KEYTYPE_RSA:
xfree(ta->pkey.key.rsa.n);
xfree(ta->pkey.key.rsa.e);
break;
case BR_KEYTYPE_EC:
xfree(ta->pkey.key.ec.q);
break;
}
}