/*
* Copyright (C) 2012 KU Leuven
* Copyright (C) 2013 Christian Grothoff
* Copyright (C) 2013 Nikos Mavrogiannopoulos
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of libdane.
*
* The libdane library is free software; you can redistribute it
* and/or modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>
*
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <unbound.h>
#include <gnutls/dane.h>
#include <gnutls/x509.h>
#include <gnutls/abstract.h>
#include <gnutls/crypto.h>
#include "../lib/gnutls_int.h"
#define MAX_DATA_ENTRIES 100
#undef gnutls_assert
#undef gnutls_assert_val
#ifdef DEBUG
#define gnutls_assert() fprintf(stderr, "ASSERT: %s: %d\n", __FILE__, __LINE__);
#define gnutls_assert_val(x) gnutls_assert_val_int(x, __FILE__, __LINE__)
static int gnutls_assert_val_int(int val, const char *file, int line)
{
fprintf(stderr, "ASSERT: %s: %d\n", file, line);
return val;
}
#else
#define gnutls_assert()
#define gnutls_assert_val(x) (x)
#endif
struct dane_state_st {
struct ub_ctx *ctx;
unsigned int flags;
};
struct dane_query_st {
struct ub_result *result;
unsigned int data_entries;
dane_cert_usage_t usage[MAX_DATA_ENTRIES];
dane_cert_type_t type[MAX_DATA_ENTRIES];
dane_match_type_t match[MAX_DATA_ENTRIES];
gnutls_datum_t data[MAX_DATA_ENTRIES];
unsigned int flags;
dane_query_status_t status;
};
/**
* dane_query_status:
* @q: The query result structure
*
* This function will return the status of the query response.
* See %dane_query_status_t for the possible types.
*
* Returns: The status type.
**/
dane_query_status_t dane_query_status(dane_query_t q)
{
return q->status;
}
/**
* dane_query_entries:
* @q: The query result structure
*
* This function will return the number of entries in a query.
*
* Returns: The number of entries.
**/
unsigned int dane_query_entries(dane_query_t q)
{
return q->data_entries;
}
/**
* dane_query_data:
* @q: The query result structure
* @idx: The index of the query response.
* @usage: The certificate usage (see %dane_cert_usage_t)
* @type: The certificate type (see %dane_cert_type_t)
* @match: The DANE matching type (see %dane_match_type_t)
* @data: The DANE data.
*
* This function will provide the DANE data from the query
* response.
*
* Returns: On success, %DANE_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int
dane_query_data(dane_query_t q, unsigned int idx,
unsigned int *usage, unsigned int *type,
unsigned int *match, gnutls_datum_t * data)
{
if (idx >= q->data_entries)
return
gnutls_assert_val(DANE_E_REQUESTED_DATA_NOT_AVAILABLE);
if (usage)
*usage = q->usage[idx];
if (type)
*type = q->type[idx];
if (match)
*match = q->match[idx];
if (data) {
data->data = q->data[idx].data;
data->size = q->data[idx].size;
}
return DANE_E_SUCCESS;
}
/**
* dane_query_to_raw_tlsa:
* @q: The query result structure
* @data_entries: Pointer set to the number of entries in the query
* @dane_data: Pointer to contain an array of DNS rdata items, terminated with a NULL pointer;
* caller must guarantee that the referenced data remains
* valid until dane_query_deinit() is called.
* @dane_data_len: Pointer to contain the length n bytes of the dane_data items
* @secure: Pointer set true if the result is validated securely, false if
* validation failed or the domain queried has no security info
* @bogus: Pointer set true if the result was not secure due to a security failure
*
* This function will provide the DANE data from the query
* response.
*
* The pointers dane_data and dane_data_len are allocated with gnutls_malloc()
* to contain the data from the query result structure (individual
* @dane_data items simply point to the original data and are not allocated separately).
* The returned @dane_data are only valid during the lifetime of @q.
*
* Returns: On success, %DANE_E_SUCCESS (0) is returned, otherwise a
* negative error value.
*/
int
dane_query_to_raw_tlsa(dane_query_t q, unsigned int *data_entries,
char ***dane_data, int **dane_data_len, int *secure, int *bogus)
{
size_t data_sz;
char *data_buf;
unsigned int idx;
*data_entries = 0;
*dane_data = NULL;
*dane_data_len = NULL;
if (secure) {
if (q->status & DANE_QUERY_DNSSEC_VERIFIED)
*secure = 1;
else
*secure = 0;
}
if (bogus) {
if (q->status & DANE_QUERY_BOGUS)
*bogus = 1;
else
*bogus = 0;
}
/* pack dane_data pointer list followed by dane_data contents */
data_sz = sizeof (**dane_data) * (q->data_entries + 1);
for (idx = 0; idx < q->data_entries; idx++)
data_sz += 3 + q->data[idx].size;
*dane_data = gnutls_calloc (1, data_sz);
if (*dane_data == NULL)
return DANE_E_MEMORY_ERROR;
data_buf = (char *)*dane_data;
data_buf += sizeof (**dane_data) * (q->data_entries + 1);
*dane_data_len = gnutls_calloc (q->data_entries + 1, sizeof (**dane_data_len));
if (*dane_data_len == NULL) {
free(*dane_data);
*dane_data = NULL;
return DANE_E_MEMORY_ERROR;
}
for (idx = 0; idx < q->data_entries; idx++) {
(*dane_data)[idx] = data_buf;
(*dane_data)[idx][0] = q->usage[idx];
(*dane_data)[idx][1] = q->type[idx];
(*dane_data)[idx][2] = q->match[idx];
memcpy(&(*dane_data)[idx][3], q->data[idx].data, q->data[idx].size);
(*dane_data_len)[idx] = 3 + q->data[idx].size;
data_buf += 3 + q->data[idx].size;
}
(*dane_data)[idx] = NULL;
(*dane_data_len)[idx] = 0;
*data_entries = q->data_entries;
return DANE_E_SUCCESS;
}
/**
* dane_state_init:
* @s: The structure to be initialized
* @flags: flags from the %dane_state_flags enumeration
*
* This function will initialize the backend resolver. It is
* intended to be used in scenarios where multiple resolvings
* occur, to optimize against multiple re-initializations.
*
* Returns: On success, %DANE_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int dane_state_init(dane_state_t * s, unsigned int flags)
{
struct ub_ctx *ctx;
int ret;
*s = calloc(1, sizeof(struct dane_state_st));
if (*s == NULL)
return gnutls_assert_val(DANE_E_MEMORY_ERROR);
ctx = ub_ctx_create();
if (!ctx) {
gnutls_assert();
ret = DANE_E_INITIALIZATION_ERROR;
goto cleanup;
}
ub_ctx_debugout(ctx, stderr);
if (!(flags & DANE_F_IGNORE_LOCAL_RESOLVER)) {
if ((ret = ub_ctx_resolvconf(ctx, NULL)) != 0) {
gnutls_assert();
ret = DANE_E_INITIALIZATION_ERROR;
goto cleanup;
}
if ((ret = ub_ctx_hosts(ctx, NULL)) != 0) {
gnutls_assert();
ret = DANE_E_INITIALIZATION_ERROR;
goto cleanup;
}
}
/* read public keys for DNSSEC verification */
if (!(flags & DANE_F_IGNORE_DNSSEC)) {
if ((ret =
ub_ctx_add_ta_file(ctx,
(char *) UNBOUND_ROOT_KEY_FILE)) !=
0) {
gnutls_assert();
ret = DANE_E_INITIALIZATION_ERROR;
goto cleanup;
}
}
(*s)->ctx = ctx;
(*s)->flags = flags;
return DANE_E_SUCCESS;
cleanup:
if (ctx)
ub_ctx_delete(ctx);
free(*s);
return ret;
}
/**
* dane_state_deinit:
* @s: The structure to be deinitialized
*
* This function will deinitialize a DANE query structure.
*
**/
void dane_state_deinit(dane_state_t s)
{
ub_ctx_delete(s->ctx);
free(s);
}
/**
* dane_state_set_dlv_file:
* @s: The structure to be deinitialized
* @file: The file holding the DLV keys.
*
* This function will set a file with trusted keys
* for DLV (DNSSEC Lookaside Validation).
*
**/
int dane_state_set_dlv_file(dane_state_t s, const char *file)
{
int ret;
ret =
ub_ctx_set_option(s->ctx, (char *) "dlv-anchor-file:",
(void *) file);
if (ret != 0)
return gnutls_assert_val(DANE_E_FILE_ERROR);
return 0;
}
/**
* dane_query_deinit:
* @q: The structure to be deinitialized
*
* This function will deinitialize a DANE query result structure.
*
**/
void dane_query_deinit(dane_query_t q)
{
if (q->result)
ub_resolve_free(q->result);
free(q);
}
/**
* dane_raw_tlsa:
* @s: The DANE state structure
* @r: A structure to place the result
* @dane_data: array of DNS rdata items, terminated with a NULL pointer;
* caller must guarantee that the referenced data remains
* valid until dane_query_deinit() is called.
* @dane_data_len: the length n bytes of the dane_data items
* @secure: true if the result is validated securely, false if
* validation failed or the domain queried has no security info
* @bogus: if the result was not secure (secure = 0) due to a security failure,
* and the result is due to a security failure, bogus is true.
*
* This function will fill in the TLSA (DANE) structure from
* the given raw DNS record data. The @dane_data must be valid
* during the lifetime of the query.
*
* Returns: On success, %DANE_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int
dane_raw_tlsa(dane_state_t s, dane_query_t * r, char *const *dane_data,
const int *dane_data_len, int secure, int bogus)
{
int ret = DANE_E_SUCCESS;
unsigned int i;
*r = calloc(1, sizeof(struct dane_query_st));
if (*r == NULL)
return gnutls_assert_val(DANE_E_MEMORY_ERROR);
(*r)->data_entries = 0;
for (i = 0; i < MAX_DATA_ENTRIES; i++) {
if (dane_data[i] == NULL)
break;
if (dane_data_len[i] <= 3)
return
gnutls_assert_val
(DANE_E_RECEIVED_CORRUPT_DATA);
(*r)->usage[i] = dane_data[i][0];
(*r)->type[i] = dane_data[i][1];
(*r)->match[i] = dane_data[i][2];
(*r)->data[i].data = (void *) &dane_data[i][3];
(*r)->data[i].size = dane_data_len[i] - 3;
(*r)->data_entries++;
}
if (!(s->flags & DANE_F_INSECURE) && !secure) {
if (bogus)
ret = gnutls_assert_val(DANE_E_INVALID_DNSSEC_SIG);
else
ret = gnutls_assert_val(DANE_E_NO_DNSSEC_SIG);
}
/* show security status */
if (secure) {
(*r)->status = DANE_QUERY_DNSSEC_VERIFIED;
} else if (bogus) {
gnutls_assert();
(*r)->status = DANE_QUERY_BOGUS;
} else {
gnutls_assert();
(*r)->status = DANE_QUERY_NO_DNSSEC;
}
return ret;
}
/**
* dane_query_tlsa:
* @s: The DANE state structure
* @r: A structure to place the result
* @host: The host name to resolve.
* @proto: The protocol type (tcp, udp, etc.)
* @port: The service port number (eg. 443).
*
* This function will query the DNS server for the TLSA (DANE)
* data for the given host.
*
* Returns: On success, %DANE_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int
dane_query_tlsa(dane_state_t s, dane_query_t * r, const char *host,
const char *proto, unsigned int port)
{
char ns[1024];
int ret;
struct ub_result *result;
snprintf(ns, sizeof(ns), "_%u._%s.%s", port, proto, host);
/* query for webserver */
ret = ub_resolve(s->ctx, ns, 52, 1, &result);
if (ret != 0) {
return gnutls_assert_val(DANE_E_RESOLVING_ERROR);
}
/* show first result */
if (!result->havedata) {
ub_resolve_free(result);
return gnutls_assert_val(DANE_E_NO_DANE_DATA);
}
ret =
dane_raw_tlsa(s, r, result->data, result->len, result->secure,
result->bogus);
if (*r == NULL) {
ub_resolve_free(result);
return ret;
}
(*r)->result = result;
return ret;
}
static unsigned int
matches(const gnutls_datum_t * raw1, const gnutls_datum_t * raw2,
dane_match_type_t match)
{
uint8_t digest[64];
int ret;
if (match == DANE_MATCH_EXACT) {
if (raw1->size != raw2->size)
return gnutls_assert_val(0);
if (memcmp(raw1->data, raw2->data, raw1->size) != 0)
return gnutls_assert_val(0);
return 1;
} else if (match == DANE_MATCH_SHA2_256) {
if (raw2->size != 32)
return gnutls_assert_val(0);
ret =
gnutls_hash_fast(GNUTLS_DIG_SHA256, raw1->data,
raw1->size, digest);
if (ret < 0)
return gnutls_assert_val(0);
if (memcmp(digest, raw2->data, 32) != 0)
return gnutls_assert_val(0);
return 1;
} else if (match == DANE_MATCH_SHA2_512) {
if (raw2->size != 64)
return gnutls_assert_val(0);
ret =
gnutls_hash_fast(GNUTLS_DIG_SHA512, raw1->data,
raw1->size, digest);
if (ret < 0)
return gnutls_assert_val(0);
if (memcmp(digest, raw2->data, 64) != 0)
return gnutls_assert_val(0);
return 1;
}
return gnutls_assert_val(0);
}
static int
crt_to_pubkey(const gnutls_datum_t * raw_crt, gnutls_datum_t * out)
{
gnutls_pubkey_t pub = NULL;
gnutls_x509_crt_t crt = NULL;
int ret;
out->data = NULL;
ret = gnutls_x509_crt_init(&crt);
if (ret < 0)
return gnutls_assert_val(DANE_E_PUBKEY_ERROR);
ret = gnutls_pubkey_init(&pub);
if (ret < 0) {
gnutls_assert();
ret = DANE_E_PUBKEY_ERROR;
goto cleanup;
}
ret = gnutls_x509_crt_import(crt, raw_crt, GNUTLS_X509_FMT_DER);
if (ret < 0) {
gnutls_assert();
ret = DANE_E_PUBKEY_ERROR;
goto cleanup;
}
ret = gnutls_pubkey_import_x509(pub, crt, 0);
if (ret < 0) {
gnutls_assert();
ret = DANE_E_PUBKEY_ERROR;
goto cleanup;
}
ret = gnutls_pubkey_export2(pub, GNUTLS_X509_FMT_DER, out);
if (ret < 0) {
gnutls_assert();
ret = DANE_E_PUBKEY_ERROR;
goto cleanup;
}
ret = 0;
goto clean_certs;
cleanup:
free(out->data);
out->data = NULL;
clean_certs:
if (pub)
gnutls_pubkey_deinit(pub);
if (crt)
gnutls_x509_crt_deinit(crt);
return ret;
}
static int
verify_ca(const gnutls_datum_t * raw_crt, unsigned raw_crt_size,
gnutls_certificate_type_t crt_type,
dane_cert_type_t ctype,
dane_match_type_t match, gnutls_datum_t * data,
unsigned int *verify)
{
gnutls_datum_t pubkey = { NULL, 0 };
int ret, i;
unsigned int vstatus = 0;
gnutls_x509_crt_t crt = NULL, ca = NULL;
unsigned is_ok = 0;
if (raw_crt_size < 2) /* we cannot verify the CA */
return gnutls_assert_val(DANE_E_UNKNOWN_DANE_DATA);
if (ctype == DANE_CERT_X509 && crt_type == GNUTLS_CRT_X509) {
is_ok = 0;
for (i=raw_crt_size-1;i>=1;i--) {
if (matches(&raw_crt[i], data, match)) {
is_ok = 1;
break;
}
}
if (is_ok == 0) {
gnutls_assert();
*verify |= DANE_VERIFY_CA_CONSTRAINTS_VIOLATED;
}
} else if (ctype == DANE_CERT_PK && crt_type == GNUTLS_CRT_X509) {
is_ok = 0;
for (i=raw_crt_size-1;i>=1;i--) {
ret = crt_to_pubkey(&raw_crt[i], &pubkey);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
if (matches(&pubkey, data, match)) {
is_ok = 1;
break;
}
free(pubkey.data);
pubkey.data = NULL;
}
if (is_ok == 0) {
gnutls_assert();
*verify |= DANE_VERIFY_CA_CONSTRAINTS_VIOLATED;
}
} else {
ret = gnutls_assert_val(DANE_E_UNKNOWN_DANE_DATA);
goto cleanup;
}
/* check if the certificate chain is actually a chain */
ret = gnutls_x509_crt_init(&crt);
if (ret < 0) {
ret = gnutls_assert_val(DANE_E_CERT_ERROR);
goto cleanup;
}
ret =
gnutls_x509_crt_import(crt, &raw_crt[0], GNUTLS_X509_FMT_DER);
if (ret < 0) {
ret = gnutls_assert_val(DANE_E_CERT_ERROR);
goto cleanup;
}
for (i=raw_crt_size-1;i>=1;i--) {
ret = gnutls_x509_crt_init(&ca);
if (ret < 0) {
ret = gnutls_assert_val(DANE_E_CERT_ERROR);
goto cleanup;
}
ret = gnutls_x509_crt_import(ca, &raw_crt[i], GNUTLS_X509_FMT_DER);
if (ret < 0) {
ret = gnutls_assert_val(DANE_E_CERT_ERROR);
goto cleanup;
}
ret = gnutls_x509_crt_check_issuer(crt, ca);
if (ret != 0)
break;
gnutls_x509_crt_deinit(ca);
ca = NULL;
}
if (ca == NULL) {
gnutls_assert();
*verify |= DANE_VERIFY_CA_CONSTRAINTS_VIOLATED;
} else {
ret = gnutls_x509_crt_verify(crt, &ca, 1, 0, &vstatus);
if (ret < 0) {
ret = gnutls_assert_val(DANE_E_CERT_ERROR);
goto cleanup;
}
if (vstatus != 0)
*verify |= DANE_VERIFY_CA_CONSTRAINTS_VIOLATED;
}
ret = 0;
cleanup:
free(pubkey.data);
if (crt != NULL)
gnutls_x509_crt_deinit(crt);
if (ca != NULL)
gnutls_x509_crt_deinit(ca);
return ret;
}
static int
verify_ee(const gnutls_datum_t * raw_crt,
gnutls_certificate_type_t crt_type, dane_cert_type_t ctype,
dane_match_type_t match, gnutls_datum_t * data,
unsigned int *verify)
{
gnutls_datum_t pubkey = { NULL, 0 };
int ret;
if (ctype == DANE_CERT_X509 && crt_type == GNUTLS_CRT_X509) {
if (!matches(raw_crt, data, match)) {
gnutls_assert();
*verify |= DANE_VERIFY_CERT_DIFFERS;
}
} else if (ctype == DANE_CERT_PK && crt_type == GNUTLS_CRT_X509) {
ret = crt_to_pubkey(raw_crt, &pubkey);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
if (!matches(&pubkey, data, match)) {
gnutls_assert();
*verify |= DANE_VERIFY_CERT_DIFFERS;
}
} else {
ret = gnutls_assert_val(DANE_E_UNKNOWN_DANE_DATA);
goto cleanup;
}
ret = 0;
cleanup:
free(pubkey.data);
return ret;
}
#define CHECK_VRET(ret, checked, record_status, status) \
if (ret == DANE_E_UNKNOWN_DANE_DATA) { \
/* skip that entry */ \
continue; \
} else if (ret < 0) { \
gnutls_assert(); \
goto cleanup; \
} \
checked = 1; \
if (record_status == 0) { \
status = 0; \
break; \
} else { \
status |= record_status; \
}
/**
* dane_verify_crt_raw:
* @s: A DANE state structure (may be NULL)
* @chain: A certificate chain
* @chain_size: The size of the chain
* @chain_type: The type of the certificate chain
* @r: DANE data to check against
* @sflags: Flags for the initialization of @s (if NULL)
* @vflags: Verification flags; an OR'ed list of %dane_verify_flags_t.
* @verify: An OR'ed list of %dane_verify_status_t.
*
* This is the low-level function of dane_verify_crt(). See the
* high level function for documentation.
*
* This function does not perform any resolving, it utilizes
* cached entries from @r.
*
* Returns: a negative error code on error and %DANE_E_SUCCESS (0)
* when the DANE entries were successfully parsed, irrespective of
* whether they were verified (see @verify for that information). If
* no usable entries were encountered %DANE_E_REQUESTED_DATA_NOT_AVAILABLE
* will be returned.
*
**/
int
dane_verify_crt_raw(dane_state_t s,
const gnutls_datum_t * chain, unsigned chain_size,
gnutls_certificate_type_t chain_type,
dane_query_t r,
unsigned int sflags, unsigned int vflags,
unsigned int *verify)
{
int ret;
unsigned checked = 0;
unsigned int usage, type, match, idx;
gnutls_datum_t data;
if (chain_type != GNUTLS_CRT_X509)
return gnutls_assert_val(DANE_E_INVALID_REQUEST);
if (chain_size == 0)
return gnutls_assert_val(DANE_E_NO_CERT);
*verify = 0;
idx = 0;
do {
unsigned int record_verify = 0;
ret =
dane_query_data(r, idx++, &usage, &type, &match,
&data);
if (ret == DANE_E_REQUESTED_DATA_NOT_AVAILABLE)
break;
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
if (!(vflags & DANE_VFLAG_ONLY_CHECK_EE_USAGE)
&& (usage == DANE_CERT_USAGE_LOCAL_CA
|| usage == DANE_CERT_USAGE_CA)) {
ret =
verify_ca(chain, chain_size, chain_type, type,
match, &data, &record_verify);
CHECK_VRET(ret, checked, record_verify, *verify);
} else if (!(vflags & DANE_VFLAG_ONLY_CHECK_CA_USAGE)
&& (usage == DANE_CERT_USAGE_LOCAL_EE
|| usage == DANE_CERT_USAGE_EE)) {
ret =
verify_ee(&chain[0], chain_type, type, match,
&data, &record_verify);
CHECK_VRET(ret, checked, record_verify, *verify);
}
}
while (1);
if ((vflags & DANE_VFLAG_FAIL_IF_NOT_CHECKED) && checked == 0) {
ret =
gnutls_assert_val(DANE_E_REQUESTED_DATA_NOT_AVAILABLE);
} else if (checked == 0) {
*verify |= DANE_VERIFY_UNKNOWN_DANE_INFO;
} else {
ret = 0;
}
cleanup:
return ret;
}
/**
* dane_verify_crt:
* @s: A DANE state structure (may be NULL)
* @chain: A certificate chain
* @chain_size: The size of the chain
* @chain_type: The type of the certificate chain
* @hostname: The hostname associated with the chain
* @proto: The protocol of the service connecting (e.g. tcp)
* @port: The port of the service connecting (e.g. 443)
* @sflags: Flags for the initialization of @s (if NULL)
* @vflags: Verification flags; an OR'ed list of %dane_verify_flags_t.
* @verify: An OR'ed list of %dane_verify_status_t.
*
* This function will verify the given certificate chain against the
* CA constrains and/or the certificate available via DANE.
* If no information via DANE can be obtained the flag %DANE_VERIFY_NO_DANE_INFO
* is set. If a DNSSEC signature is not available for the DANE
* record then the verify flag %DANE_VERIFY_NO_DNSSEC_DATA is set.
*
* Due to the many possible options of DANE, there is no single threat
* model countered. When notifying the user about DANE verification results
* it may be better to mention: DANE verification did not reject the certificate,
* rather than mentioning a successful DANE verication.
*
* Note that this function is designed to be run in addition to
* PKIX - certificate chain - verification. To be run independently
* the %DANE_VFLAG_ONLY_CHECK_EE_USAGE flag should be specified;
* then the function will check whether the key of the peer matches the
* key advertized in the DANE entry.
*
* Returns: a negative error code on error and %DANE_E_SUCCESS (0)
* when the DANE entries were successfully parsed, irrespective of
* whether they were verified (see @verify for that information). If
* no usable entries were encountered %DANE_E_REQUESTED_DATA_NOT_AVAILABLE
* will be returned.
*
**/
int
dane_verify_crt(dane_state_t s,
const gnutls_datum_t * chain, unsigned chain_size,
gnutls_certificate_type_t chain_type,
const char *hostname, const char *proto, unsigned int port,
unsigned int sflags, unsigned int vflags,
unsigned int *verify)
{
dane_state_t state = NULL;
dane_query_t r = NULL;
int ret;
*verify = 0;
if (s == NULL) {
ret = dane_state_init(&state, sflags);
if (ret < 0) {
gnutls_assert();
return ret;
}
} else
state = s;
ret = dane_query_tlsa(state, &r, hostname, proto, port);
if (ret < 0) {
gnutls_assert();
goto cleanup;
}
ret = dane_verify_crt_raw(state, chain, chain_size, chain_type,
r, sflags, vflags, verify);
cleanup:
if (state != s)
dane_state_deinit(state);
if (r != NULL)
dane_query_deinit(r);
return ret;
}
/**
* dane_verify_session_crt:
* @s: A DANE state structure (may be NULL)
* @session: A gnutls session
* @hostname: The hostname associated with the chain
* @proto: The protocol of the service connecting (e.g. tcp)
* @port: The port of the service connecting (e.g. 443)
* @sflags: Flags for the initialization of @s (if NULL)
* @vflags: Verification flags; an OR'ed list of %dane_verify_flags_t.
* @verify: An OR'ed list of %dane_verify_status_t.
*
* This function will verify session's certificate chain against the
* CA constrains and/or the certificate available via DANE.
* See dane_verify_crt() for more information.
*
* This will not verify the chain for validity; unless the DANE
* verification is restricted to end certificates, this must be
* be performed separately using gnutls_certificate_verify_peers3().
*
* Returns: a negative error code on error and %DANE_E_SUCCESS (0)
* when the DANE entries were successfully parsed, irrespective of
* whether they were verified (see @verify for that information). If
* no usable entries were encountered %DANE_E_REQUESTED_DATA_NOT_AVAILABLE
* will be returned.
*
**/
int
dane_verify_session_crt(dane_state_t s,
gnutls_session_t session,
const char *hostname, const char *proto,
unsigned int port, unsigned int sflags,
unsigned int vflags, unsigned int *verify)
{
const gnutls_datum_t *cert_list;
unsigned int cert_list_size = 0;
unsigned int type;
int ret;
cert_list = gnutls_certificate_get_peers(session, &cert_list_size);
if (cert_list_size == 0) {
return gnutls_assert_val(DANE_E_NO_CERT);
}
type = gnutls_certificate_type_get(session);
/* this list may be incomplete, try to get the self-signed CA if any */
if (cert_list_size > 0) {
gnutls_x509_crt_t crt, ca;
gnutls_certificate_credentials_t sc;
ret = gnutls_x509_crt_init(&crt);
if (ret < 0) {
gnutls_assert();
goto failsafe;
}
ret = gnutls_x509_crt_import(crt, &cert_list[cert_list_size-1], GNUTLS_X509_FMT_DER);
if (ret < 0) {
gnutls_assert();
gnutls_x509_crt_deinit(crt);
goto failsafe;
}
/* if it is already self signed continue normally */
ret = gnutls_x509_crt_check_issuer(crt, crt);
if (ret != 0) {
gnutls_assert();
gnutls_x509_crt_deinit(crt);
goto failsafe;
}
/* chain does not finish in a self signed cert, try to obtain the issuer */
ret = gnutls_credentials_get(session, GNUTLS_CRD_CERTIFICATE, (void**)&sc);
if (ret < 0) {
gnutls_assert();
gnutls_x509_crt_deinit(crt);
goto failsafe;
}
ret = gnutls_certificate_get_issuer(sc, crt, &ca, 0);
if (ret < 0) {
gnutls_assert();
gnutls_x509_crt_deinit(crt);
goto failsafe;
}
/* make the new list */
gnutls_datum_t *new_cert_list;
new_cert_list = gnutls_malloc((cert_list_size + 1) * sizeof(gnutls_datum_t));
if (new_cert_list == NULL) {
gnutls_assert();
gnutls_x509_crt_deinit(crt);
goto failsafe;
}
memcpy(new_cert_list, cert_list, cert_list_size*sizeof(gnutls_datum_t));
ret = gnutls_x509_crt_export2(ca, GNUTLS_X509_FMT_DER, &new_cert_list[cert_list_size]);
if (ret < 0) {
gnutls_assert();
free(new_cert_list);
gnutls_x509_crt_deinit(crt);
goto failsafe;
}
ret = dane_verify_crt(s, new_cert_list, cert_list_size+1, type,
hostname, proto, port, sflags, vflags,
verify);
if (ret < 0) {
gnutls_assert();
}
gnutls_free(new_cert_list[cert_list_size].data);
free(new_cert_list);
return ret;
}
failsafe:
return dane_verify_crt(s, cert_list, cert_list_size, type,
hostname, proto, port, sflags, vflags,
verify);
}
/**
* dane_verification_status_print:
* @status: The status flags to be printed
* @type: The certificate type
* @out: Newly allocated datum with (0) terminated string.
* @flags: should be zero
*
* This function will pretty print the status of a verification
* process -- eg. the one obtained by dane_verify_crt().
*
* The output @out needs to be deallocated using gnutls_free().
*
* Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
* negative error value.
**/
int
dane_verification_status_print(unsigned int status,
gnutls_datum_t * out, unsigned int flags)
{
gnutls_buffer_st str;
_gnutls_buffer_init(&str);
if (status == 0)
_gnutls_buffer_append_str(&str,
_("Certificate matches. "));
else
_gnutls_buffer_append_str(&str,
_("Verification failed. "));
if (status & DANE_VERIFY_CA_CONSTRAINTS_VIOLATED)
_gnutls_buffer_append_str(&str,
_
("CA constrains were violated. "));
if (status & DANE_VERIFY_CERT_DIFFERS)
_gnutls_buffer_append_str(&str,
_("The certificate differs. "));
if (status & DANE_VERIFY_NO_DANE_INFO)
_gnutls_buffer_append_str(&str,
_
("There were no DANE information. "));
return _gnutls_buffer_to_datum(&str, out, 1);
}