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openssl/crypto/x509/x509_vfy.c
Pauli a1df06b363 This has been added to avoid the situation where some host ctype.h functions 
return true for characters > 127.  I.e. they are allowing extended ASCII
characters through which then cause problems.  E.g. marking superscript '2' as
a number then causes the common (ch - '0') conversion to number to fail
miserably.  Likewise letters with diacritical marks can also cause problems.

If a non-ASCII character set is being used (currently only EBCDIC), it is
adjusted for.

The implementation uses a single table with a bit for each of the defined
classes.  These functions accept an int argument and fail for
values out of range or for characters outside of the ASCII set.  They will
work for both signed and unsigned character inputs.

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4102)
2017-08-22 09:45:25 +10:00

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/*
* Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include <time.h>
#include <errno.h>
#include <limits.h>
#include "internal/ctype.h"
#include "internal/cryptlib.h"
#include <openssl/crypto.h>
#include <openssl/lhash.h>
#include <openssl/buffer.h>
#include <openssl/evp.h>
#include <openssl/asn1.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/objects.h>
#include <internal/dane.h>
#include <internal/x509_int.h>
#include "x509_lcl.h"
/* CRL score values */
/* No unhandled critical extensions */
#define CRL_SCORE_NOCRITICAL 0x100
/* certificate is within CRL scope */
#define CRL_SCORE_SCOPE 0x080
/* CRL times valid */
#define CRL_SCORE_TIME 0x040
/* Issuer name matches certificate */
#define CRL_SCORE_ISSUER_NAME 0x020
/* If this score or above CRL is probably valid */
#define CRL_SCORE_VALID (CRL_SCORE_NOCRITICAL|CRL_SCORE_TIME|CRL_SCORE_SCOPE)
/* CRL issuer is certificate issuer */
#define CRL_SCORE_ISSUER_CERT 0x018
/* CRL issuer is on certificate path */
#define CRL_SCORE_SAME_PATH 0x008
/* CRL issuer matches CRL AKID */
#define CRL_SCORE_AKID 0x004
/* Have a delta CRL with valid times */
#define CRL_SCORE_TIME_DELTA 0x002
static int build_chain(X509_STORE_CTX *ctx);
static int verify_chain(X509_STORE_CTX *ctx);
static int dane_verify(X509_STORE_CTX *ctx);
static int null_callback(int ok, X509_STORE_CTX *e);
static int check_issued(X509_STORE_CTX *ctx, X509 *x, X509 *issuer);
static X509 *find_issuer(X509_STORE_CTX *ctx, STACK_OF(X509) *sk, X509 *x);
static int check_chain_extensions(X509_STORE_CTX *ctx);
static int check_name_constraints(X509_STORE_CTX *ctx);
static int check_id(X509_STORE_CTX *ctx);
static int check_trust(X509_STORE_CTX *ctx, int num_untrusted);
static int check_revocation(X509_STORE_CTX *ctx);
static int check_cert(X509_STORE_CTX *ctx);
static int check_policy(X509_STORE_CTX *ctx);
static int get_issuer_sk(X509 **issuer, X509_STORE_CTX *ctx, X509 *x);
static int check_dane_issuer(X509_STORE_CTX *ctx, int depth);
static int check_key_level(X509_STORE_CTX *ctx, X509 *cert);
static int check_sig_level(X509_STORE_CTX *ctx, X509 *cert);
static int get_crl_score(X509_STORE_CTX *ctx, X509 **pissuer,
unsigned int *preasons, X509_CRL *crl, X509 *x);
static int get_crl_delta(X509_STORE_CTX *ctx,
X509_CRL **pcrl, X509_CRL **pdcrl, X509 *x);
static void get_delta_sk(X509_STORE_CTX *ctx, X509_CRL **dcrl,
int *pcrl_score, X509_CRL *base,
STACK_OF(X509_CRL) *crls);
static void crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl, X509 **pissuer,
int *pcrl_score);
static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
unsigned int *preasons);
static int check_crl_path(X509_STORE_CTX *ctx, X509 *x);
static int check_crl_chain(X509_STORE_CTX *ctx,
STACK_OF(X509) *cert_path,
STACK_OF(X509) *crl_path);
static int internal_verify(X509_STORE_CTX *ctx);
static int null_callback(int ok, X509_STORE_CTX *e)
{
return ok;
}
/* Return 1 is a certificate is self signed */
static int cert_self_signed(X509 *x)
{
/*
* FIXME: x509v3_cache_extensions() needs to detect more failures and not
* set EXFLAG_SET when that happens. Especially, if the failures are
* parse errors, rather than memory pressure!
*/
X509_check_purpose(x, -1, 0);
if (x->ex_flags & EXFLAG_SS)
return 1;
else
return 0;
}
/* Given a certificate try and find an exact match in the store */
static X509 *lookup_cert_match(X509_STORE_CTX *ctx, X509 *x)
{
STACK_OF(X509) *certs;
X509 *xtmp = NULL;
int i;
/* Lookup all certs with matching subject name */
certs = ctx->lookup_certs(ctx, X509_get_subject_name(x));
if (certs == NULL)
return NULL;
/* Look for exact match */
for (i = 0; i < sk_X509_num(certs); i++) {
xtmp = sk_X509_value(certs, i);
if (!X509_cmp(xtmp, x))
break;
}
if (i < sk_X509_num(certs))
X509_up_ref(xtmp);
else
xtmp = NULL;
sk_X509_pop_free(certs, X509_free);
return xtmp;
}
/*-
* Inform the verify callback of an error.
* If B<x> is not NULL it is the error cert, otherwise use the chain cert at
* B<depth>.
* If B<err> is not X509_V_OK, that's the error value, otherwise leave
* unchanged (presumably set by the caller).
*
* Returns 0 to abort verification with an error, non-zero to continue.
*/
static int verify_cb_cert(X509_STORE_CTX *ctx, X509 *x, int depth, int err)
{
ctx->error_depth = depth;
ctx->current_cert = (x != NULL) ? x : sk_X509_value(ctx->chain, depth);
if (err != X509_V_OK)
ctx->error = err;
return ctx->verify_cb(0, ctx);
}
/*-
* Inform the verify callback of an error, CRL-specific variant. Here, the
* error depth and certificate are already set, we just specify the error
* number.
*
* Returns 0 to abort verification with an error, non-zero to continue.
*/
static int verify_cb_crl(X509_STORE_CTX *ctx, int err)
{
ctx->error = err;
return ctx->verify_cb(0, ctx);
}
static int check_auth_level(X509_STORE_CTX *ctx)
{
int i;
int num = sk_X509_num(ctx->chain);
if (ctx->param->auth_level <= 0)
return 1;
for (i = 0; i < num; ++i) {
X509 *cert = sk_X509_value(ctx->chain, i);
/*
* We've already checked the security of the leaf key, so here we only
* check the security of issuer keys.
*/
if (i > 0 && !check_key_level(ctx, cert) &&
verify_cb_cert(ctx, cert, i, X509_V_ERR_CA_KEY_TOO_SMALL) == 0)
return 0;
/*
* We also check the signature algorithm security of all certificates
* except those of the trust anchor at index num-1.
*/
if (i < num - 1 && !check_sig_level(ctx, cert) &&
verify_cb_cert(ctx, cert, i, X509_V_ERR_CA_MD_TOO_WEAK) == 0)
return 0;
}
return 1;
}
static int verify_chain(X509_STORE_CTX *ctx)
{
int err;
int ok;
/*
* Before either returning with an error, or continuing with CRL checks,
* instantiate chain public key parameters.
*/
if ((ok = build_chain(ctx)) == 0 ||
(ok = check_chain_extensions(ctx)) == 0 ||
(ok = check_auth_level(ctx)) == 0 ||
(ok = check_name_constraints(ctx)) == 0 ||
(ok = check_id(ctx)) == 0 || 1)
X509_get_pubkey_parameters(NULL, ctx->chain);
if (ok == 0 || (ok = ctx->check_revocation(ctx)) == 0)
return ok;
err = X509_chain_check_suiteb(&ctx->error_depth, NULL, ctx->chain,
ctx->param->flags);
if (err != X509_V_OK) {
if ((ok = verify_cb_cert(ctx, NULL, ctx->error_depth, err)) == 0)
return ok;
}
/* Verify chain signatures and expiration times */
ok = (ctx->verify != NULL) ? ctx->verify(ctx) : internal_verify(ctx);
if (!ok)
return ok;
#ifndef OPENSSL_NO_RFC3779
/* RFC 3779 path validation, now that CRL check has been done */
if ((ok = X509v3_asid_validate_path(ctx)) == 0)
return ok;
if ((ok = X509v3_addr_validate_path(ctx)) == 0)
return ok;
#endif
/* If we get this far evaluate policies */
if (ctx->param->flags & X509_V_FLAG_POLICY_CHECK)
ok = ctx->check_policy(ctx);
return ok;
}
int X509_verify_cert(X509_STORE_CTX *ctx)
{
SSL_DANE *dane = ctx->dane;
int ret;
if (ctx->cert == NULL) {
X509err(X509_F_X509_VERIFY_CERT, X509_R_NO_CERT_SET_FOR_US_TO_VERIFY);
ctx->error = X509_V_ERR_INVALID_CALL;
return -1;
}
if (ctx->chain != NULL) {
/*
* This X509_STORE_CTX has already been used to verify a cert. We
* cannot do another one.
*/
X509err(X509_F_X509_VERIFY_CERT, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
ctx->error = X509_V_ERR_INVALID_CALL;
return -1;
}
/*
* first we make sure the chain we are going to build is present and that
* the first entry is in place
*/
if (((ctx->chain = sk_X509_new_null()) == NULL) ||
(!sk_X509_push(ctx->chain, ctx->cert))) {
X509err(X509_F_X509_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return -1;
}
X509_up_ref(ctx->cert);
ctx->num_untrusted = 1;
/* If the peer's public key is too weak, we can stop early. */
if (!check_key_level(ctx, ctx->cert) &&
!verify_cb_cert(ctx, ctx->cert, 0, X509_V_ERR_EE_KEY_TOO_SMALL))
return 0;
if (DANETLS_ENABLED(dane))
ret = dane_verify(ctx);
else
ret = verify_chain(ctx);
/*
* Safety-net. If we are returning an error, we must also set ctx->error,
* so that the chain is not considered verified should the error be ignored
* (e.g. TLS with SSL_VERIFY_NONE).
*/
if (ret <= 0 && ctx->error == X509_V_OK)
ctx->error = X509_V_ERR_UNSPECIFIED;
return ret;
}
/*
* Given a STACK_OF(X509) find the issuer of cert (if any)
*/
static X509 *find_issuer(X509_STORE_CTX *ctx, STACK_OF(X509) *sk, X509 *x)
{
int i;
X509 *issuer, *rv = NULL;
for (i = 0; i < sk_X509_num(sk); i++) {
issuer = sk_X509_value(sk, i);
if (ctx->check_issued(ctx, x, issuer)) {
rv = issuer;
if (x509_check_cert_time(ctx, rv, -1))
break;
}
}
return rv;
}
/* Given a possible certificate and issuer check them */
static int check_issued(X509_STORE_CTX *ctx, X509 *x, X509 *issuer)
{
int ret;
if (x == issuer)
return cert_self_signed(x);
ret = X509_check_issued(issuer, x);
if (ret == X509_V_OK) {
int i;
X509 *ch;
/* Special case: single self signed certificate */
if (cert_self_signed(x) && sk_X509_num(ctx->chain) == 1)
return 1;
for (i = 0; i < sk_X509_num(ctx->chain); i++) {
ch = sk_X509_value(ctx->chain, i);
if (ch == issuer || !X509_cmp(ch, issuer)) {
ret = X509_V_ERR_PATH_LOOP;
break;
}
}
}
return (ret == X509_V_OK);
}
/* Alternative lookup method: look from a STACK stored in other_ctx */
static int get_issuer_sk(X509 **issuer, X509_STORE_CTX *ctx, X509 *x)
{
*issuer = find_issuer(ctx, ctx->other_ctx, x);
if (*issuer) {
X509_up_ref(*issuer);
return 1;
} else
return 0;
}
static STACK_OF(X509) *lookup_certs_sk(X509_STORE_CTX *ctx, X509_NAME *nm)
{
STACK_OF(X509) *sk = NULL;
X509 *x;
int i;
for (i = 0; i < sk_X509_num(ctx->other_ctx); i++) {
x = sk_X509_value(ctx->other_ctx, i);
if (X509_NAME_cmp(nm, X509_get_subject_name(x)) == 0) {
if (sk == NULL)
sk = sk_X509_new_null();
if (sk == NULL || sk_X509_push(sk, x) == 0) {
sk_X509_pop_free(sk, X509_free);
return NULL;
}
X509_up_ref(x);
}
}
return sk;
}
/*
* Check EE or CA certificate purpose. For trusted certificates explicit local
* auxiliary trust can be used to override EKU-restrictions.
*/
static int check_purpose(X509_STORE_CTX *ctx, X509 *x, int purpose, int depth,
int must_be_ca)
{
int tr_ok = X509_TRUST_UNTRUSTED;
/*
* For trusted certificates we want to see whether any auxiliary trust
* settings trump the purpose constraints.
*
* This is complicated by the fact that the trust ordinals in
* ctx->param->trust are entirely independent of the purpose ordinals in
* ctx->param->purpose!
*
* What connects them is their mutual initialization via calls from
* X509_STORE_CTX_set_default() into X509_VERIFY_PARAM_lookup() which sets
* related values of both param->trust and param->purpose. It is however
* typically possible to infer associated trust values from a purpose value
* via the X509_PURPOSE API.
*
* Therefore, we can only check for trust overrides when the purpose we're
* checking is the same as ctx->param->purpose and ctx->param->trust is
* also set.
*/
if (depth >= ctx->num_untrusted && purpose == ctx->param->purpose)
tr_ok = X509_check_trust(x, ctx->param->trust, X509_TRUST_NO_SS_COMPAT);
switch (tr_ok) {
case X509_TRUST_TRUSTED:
return 1;
case X509_TRUST_REJECTED:
break;
default:
switch (X509_check_purpose(x, purpose, must_be_ca > 0)) {
case 1:
return 1;
case 0:
break;
default:
if ((ctx->param->flags & X509_V_FLAG_X509_STRICT) == 0)
return 1;
}
break;
}
return verify_cb_cert(ctx, x, depth, X509_V_ERR_INVALID_PURPOSE);
}
/*
* Check a certificate chains extensions for consistency with the supplied
* purpose
*/
static int check_chain_extensions(X509_STORE_CTX *ctx)
{
int i, must_be_ca, plen = 0;
X509 *x;
int proxy_path_length = 0;
int purpose;
int allow_proxy_certs;
int num = sk_X509_num(ctx->chain);
/*-
* must_be_ca can have 1 of 3 values:
* -1: we accept both CA and non-CA certificates, to allow direct
* use of self-signed certificates (which are marked as CA).
* 0: we only accept non-CA certificates. This is currently not
* used, but the possibility is present for future extensions.
* 1: we only accept CA certificates. This is currently used for
* all certificates in the chain except the leaf certificate.
*/
must_be_ca = -1;
/* CRL path validation */
if (ctx->parent) {
allow_proxy_certs = 0;
purpose = X509_PURPOSE_CRL_SIGN;
} else {
allow_proxy_certs =
! !(ctx->param->flags & X509_V_FLAG_ALLOW_PROXY_CERTS);
purpose = ctx->param->purpose;
}
for (i = 0; i < num; i++) {
int ret;
x = sk_X509_value(ctx->chain, i);
if (!(ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
&& (x->ex_flags & EXFLAG_CRITICAL)) {
if (!verify_cb_cert(ctx, x, i,
X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION))
return 0;
}
if (!allow_proxy_certs && (x->ex_flags & EXFLAG_PROXY)) {
if (!verify_cb_cert(ctx, x, i,
X509_V_ERR_PROXY_CERTIFICATES_NOT_ALLOWED))
return 0;
}
ret = X509_check_ca(x);
switch (must_be_ca) {
case -1:
if ((ctx->param->flags & X509_V_FLAG_X509_STRICT)
&& (ret != 1) && (ret != 0)) {
ret = 0;
ctx->error = X509_V_ERR_INVALID_CA;
} else
ret = 1;
break;
case 0:
if (ret != 0) {
ret = 0;
ctx->error = X509_V_ERR_INVALID_NON_CA;
} else
ret = 1;
break;
default:
/* X509_V_FLAG_X509_STRICT is implicit for intermediate CAs */
if ((ret == 0)
|| ((i + 1 < num || ctx->param->flags & X509_V_FLAG_X509_STRICT)
&& (ret != 1))) {
ret = 0;
ctx->error = X509_V_ERR_INVALID_CA;
} else
ret = 1;
break;
}
if (ret == 0 && !verify_cb_cert(ctx, x, i, X509_V_OK))
return 0;
/* check_purpose() makes the callback as needed */
if (purpose > 0 && !check_purpose(ctx, x, purpose, i, must_be_ca))
return 0;
/* Check pathlen if not self issued */
if ((i > 1) && !(x->ex_flags & EXFLAG_SI)
&& (x->ex_pathlen != -1)
&& (plen > (x->ex_pathlen + proxy_path_length + 1))) {
if (!verify_cb_cert(ctx, x, i, X509_V_ERR_PATH_LENGTH_EXCEEDED))
return 0;
}
/* Increment path length if not self issued */
if (!(x->ex_flags & EXFLAG_SI))
plen++;
/*
* If this certificate is a proxy certificate, the next certificate
* must be another proxy certificate or a EE certificate. If not,
* the next certificate must be a CA certificate.
*/
if (x->ex_flags & EXFLAG_PROXY) {
/*
* RFC3820, 4.1.3 (b)(1) stipulates that if pCPathLengthConstraint
* is less than max_path_length, the former should be copied to
* the latter, and 4.1.4 (a) stipulates that max_path_length
* should be verified to be larger than zero and decrement it.
*
* Because we're checking the certs in the reverse order, we start
* with verifying that proxy_path_length isn't larger than pcPLC,
* and copy the latter to the former if it is, and finally,
* increment proxy_path_length.
*/
if (x->ex_pcpathlen != -1) {
if (proxy_path_length > x->ex_pcpathlen) {
if (!verify_cb_cert(ctx, x, i,
X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED))
return 0;
}
proxy_path_length = x->ex_pcpathlen;
}
proxy_path_length++;
must_be_ca = 0;
} else
must_be_ca = 1;
}
return 1;
}
static int check_name_constraints(X509_STORE_CTX *ctx)
{
int i;
/* Check name constraints for all certificates */
for (i = sk_X509_num(ctx->chain) - 1; i >= 0; i--) {
X509 *x = sk_X509_value(ctx->chain, i);
int j;
/* Ignore self issued certs unless last in chain */
if (i && (x->ex_flags & EXFLAG_SI))
continue;
/*
* Proxy certificates policy has an extra constraint, where the
* certificate subject MUST be the issuer with a single CN entry
* added.
* (RFC 3820: 3.4, 4.1.3 (a)(4))
*/
if (x->ex_flags & EXFLAG_PROXY) {
X509_NAME *tmpsubject = X509_get_subject_name(x);
X509_NAME *tmpissuer = X509_get_issuer_name(x);
X509_NAME_ENTRY *tmpentry = NULL;
int last_object_nid = 0;
int err = X509_V_OK;
int last_object_loc = X509_NAME_entry_count(tmpsubject) - 1;
/* Check that there are at least two RDNs */
if (last_object_loc < 1) {
err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
goto proxy_name_done;
}
/*
* Check that there is exactly one more RDN in subject as
* there is in issuer.
*/
if (X509_NAME_entry_count(tmpsubject)
!= X509_NAME_entry_count(tmpissuer) + 1) {
err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
goto proxy_name_done;
}
/*
* Check that the last subject component isn't part of a
* multivalued RDN
*/
if (X509_NAME_ENTRY_set(X509_NAME_get_entry(tmpsubject,
last_object_loc))
== X509_NAME_ENTRY_set(X509_NAME_get_entry(tmpsubject,
last_object_loc - 1))) {
err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
goto proxy_name_done;
}
/*
* Check that the last subject RDN is a commonName, and that
* all the previous RDNs match the issuer exactly
*/
tmpsubject = X509_NAME_dup(tmpsubject);
if (tmpsubject == NULL) {
X509err(X509_F_CHECK_NAME_CONSTRAINTS, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
tmpentry =
X509_NAME_delete_entry(tmpsubject, last_object_loc);
last_object_nid =
OBJ_obj2nid(X509_NAME_ENTRY_get_object(tmpentry));
if (last_object_nid != NID_commonName
|| X509_NAME_cmp(tmpsubject, tmpissuer) != 0) {
err = X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION;
}
X509_NAME_ENTRY_free(tmpentry);
X509_NAME_free(tmpsubject);
proxy_name_done:
if (err != X509_V_OK
&& !verify_cb_cert(ctx, x, i, err))
return 0;
}
/*
* Check against constraints for all certificates higher in chain
* including trust anchor. Trust anchor not strictly speaking needed
* but if it includes constraints it is to be assumed it expects them
* to be obeyed.
*/
for (j = sk_X509_num(ctx->chain) - 1; j > i; j--) {
NAME_CONSTRAINTS *nc = sk_X509_value(ctx->chain, j)->nc;
if (nc) {
int rv = NAME_CONSTRAINTS_check(x, nc);
/* If EE certificate check commonName too */
if (rv == X509_V_OK && i == 0)
rv = NAME_CONSTRAINTS_check_CN(x, nc);
switch (rv) {
case X509_V_OK:
break;
case X509_V_ERR_OUT_OF_MEM:
return 0;
default:
if (!verify_cb_cert(ctx, x, i, rv))
return 0;
break;
}
}
}
}
return 1;
}
static int check_id_error(X509_STORE_CTX *ctx, int errcode)
{
return verify_cb_cert(ctx, ctx->cert, 0, errcode);
}
static int check_hosts(X509 *x, X509_VERIFY_PARAM *vpm)
{
int i;
int n = sk_OPENSSL_STRING_num(vpm->hosts);
char *name;
if (vpm->peername != NULL) {
OPENSSL_free(vpm->peername);
vpm->peername = NULL;
}
for (i = 0; i < n; ++i) {
name = sk_OPENSSL_STRING_value(vpm->hosts, i);
if (X509_check_host(x, name, 0, vpm->hostflags, &vpm->peername) > 0)
return 1;
}
return n == 0;
}
static int check_id(X509_STORE_CTX *ctx)
{
X509_VERIFY_PARAM *vpm = ctx->param;
X509 *x = ctx->cert;
if (vpm->hosts && check_hosts(x, vpm) <= 0) {
if (!check_id_error(ctx, X509_V_ERR_HOSTNAME_MISMATCH))
return 0;
}
if (vpm->email && X509_check_email(x, vpm->email, vpm->emaillen, 0) <= 0) {
if (!check_id_error(ctx, X509_V_ERR_EMAIL_MISMATCH))
return 0;
}
if (vpm->ip && X509_check_ip(x, vpm->ip, vpm->iplen, 0) <= 0) {
if (!check_id_error(ctx, X509_V_ERR_IP_ADDRESS_MISMATCH))
return 0;
}
return 1;
}
static int check_trust(X509_STORE_CTX *ctx, int num_untrusted)
{
int i;
X509 *x = NULL;
X509 *mx;
SSL_DANE *dane = ctx->dane;
int num = sk_X509_num(ctx->chain);
int trust;
/*
* Check for a DANE issuer at depth 1 or greater, if it is a DANE-TA(2)
* match, we're done, otherwise we'll merely record the match depth.
*/
if (DANETLS_HAS_TA(dane) && num_untrusted > 0 && num_untrusted < num) {
switch (trust = check_dane_issuer(ctx, num_untrusted)) {
case X509_TRUST_TRUSTED:
case X509_TRUST_REJECTED:
return trust;
}
}
/*
* Check trusted certificates in chain at depth num_untrusted and up.
* Note, that depths 0..num_untrusted-1 may also contain trusted
* certificates, but the caller is expected to have already checked those,
* and wants to incrementally check just any added since.
*/
for (i = num_untrusted; i < num; i++) {
x = sk_X509_value(ctx->chain, i);
trust = X509_check_trust(x, ctx->param->trust, 0);
/* If explicitly trusted return trusted */
if (trust == X509_TRUST_TRUSTED)
goto trusted;
if (trust == X509_TRUST_REJECTED)
goto rejected;
}
/*
* If we are looking at a trusted certificate, and accept partial chains,
* the chain is PKIX trusted.
*/
if (num_untrusted < num) {
if (ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN)
goto trusted;
return X509_TRUST_UNTRUSTED;
}
if (num_untrusted == num && ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN) {
/*
* Last-resort call with no new trusted certificates, check the leaf
* for a direct trust store match.
*/
i = 0;
x = sk_X509_value(ctx->chain, i);
mx = lookup_cert_match(ctx, x);
if (!mx)
return X509_TRUST_UNTRUSTED;
/*
* Check explicit auxiliary trust/reject settings. If none are set,
* we'll accept X509_TRUST_UNTRUSTED when not self-signed.
*/
trust = X509_check_trust(mx, ctx->param->trust, 0);
if (trust == X509_TRUST_REJECTED) {
X509_free(mx);
goto rejected;
}
/* Replace leaf with trusted match */
(void) sk_X509_set(ctx->chain, 0, mx);
X509_free(x);
ctx->num_untrusted = 0;
goto trusted;
}
/*
* If no trusted certs in chain at all return untrusted and allow
* standard (no issuer cert) etc errors to be indicated.
*/
return X509_TRUST_UNTRUSTED;
rejected:
if (!verify_cb_cert(ctx, x, i, X509_V_ERR_CERT_REJECTED))
return X509_TRUST_REJECTED;
return X509_TRUST_UNTRUSTED;
trusted:
if (!DANETLS_ENABLED(dane))
return X509_TRUST_TRUSTED;
if (dane->pdpth < 0)
dane->pdpth = num_untrusted;
/* With DANE, PKIX alone is not trusted until we have both */
if (dane->mdpth >= 0)
return X509_TRUST_TRUSTED;
return X509_TRUST_UNTRUSTED;
}
static int check_revocation(X509_STORE_CTX *ctx)
{
int i = 0, last = 0, ok = 0;
if (!(ctx->param->flags & X509_V_FLAG_CRL_CHECK))
return 1;
if (ctx->param->flags & X509_V_FLAG_CRL_CHECK_ALL)
last = sk_X509_num(ctx->chain) - 1;
else {
/* If checking CRL paths this isn't the EE certificate */
if (ctx->parent)
return 1;
last = 0;
}
for (i = 0; i <= last; i++) {
ctx->error_depth = i;
ok = check_cert(ctx);
if (!ok)
return ok;
}
return 1;
}
static int check_cert(X509_STORE_CTX *ctx)
{
X509_CRL *crl = NULL, *dcrl = NULL;
int ok = 0;
int cnum = ctx->error_depth;
X509 *x = sk_X509_value(ctx->chain, cnum);
ctx->current_cert = x;
ctx->current_issuer = NULL;
ctx->current_crl_score = 0;
ctx->current_reasons = 0;
if (x->ex_flags & EXFLAG_PROXY)
return 1;
while (ctx->current_reasons != CRLDP_ALL_REASONS) {
unsigned int last_reasons = ctx->current_reasons;
/* Try to retrieve relevant CRL */
if (ctx->get_crl)
ok = ctx->get_crl(ctx, &crl, x);
else
ok = get_crl_delta(ctx, &crl, &dcrl, x);
/*
* If error looking up CRL, nothing we can do except notify callback
*/
if (!ok) {
ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);
goto done;
}
ctx->current_crl = crl;
ok = ctx->check_crl(ctx, crl);
if (!ok)
goto done;
if (dcrl) {
ok = ctx->check_crl(ctx, dcrl);
if (!ok)
goto done;
ok = ctx->cert_crl(ctx, dcrl, x);
if (!ok)
goto done;
} else
ok = 1;
/* Don't look in full CRL if delta reason is removefromCRL */
if (ok != 2) {
ok = ctx->cert_crl(ctx, crl, x);
if (!ok)
goto done;
}
X509_CRL_free(crl);
X509_CRL_free(dcrl);
crl = NULL;
dcrl = NULL;
/*
* If reasons not updated we won't get anywhere by another iteration,
* so exit loop.
*/
if (last_reasons == ctx->current_reasons) {
ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);
goto done;
}
}
done:
X509_CRL_free(crl);
X509_CRL_free(dcrl);
ctx->current_crl = NULL;
return ok;
}
/* Check CRL times against values in X509_STORE_CTX */
static int check_crl_time(X509_STORE_CTX *ctx, X509_CRL *crl, int notify)
{
time_t *ptime;
int i;
if (notify)
ctx->current_crl = crl;
if (ctx->param->flags & X509_V_FLAG_USE_CHECK_TIME)
ptime = &ctx->param->check_time;
else if (ctx->param->flags & X509_V_FLAG_NO_CHECK_TIME)
return 1;
else
ptime = NULL;
i = X509_cmp_time(X509_CRL_get0_lastUpdate(crl), ptime);
if (i == 0) {
if (!notify)
return 0;
if (!verify_cb_crl(ctx, X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD))
return 0;
}
if (i > 0) {
if (!notify)
return 0;
if (!verify_cb_crl(ctx, X509_V_ERR_CRL_NOT_YET_VALID))
return 0;
}
if (X509_CRL_get0_nextUpdate(crl)) {
i = X509_cmp_time(X509_CRL_get0_nextUpdate(crl), ptime);
if (i == 0) {
if (!notify)
return 0;
if (!verify_cb_crl(ctx, X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD))
return 0;
}
/* Ignore expiry of base CRL is delta is valid */
if ((i < 0) && !(ctx->current_crl_score & CRL_SCORE_TIME_DELTA)) {
if (!notify)
return 0;
if (!verify_cb_crl(ctx, X509_V_ERR_CRL_HAS_EXPIRED))
return 0;
}
}
if (notify)
ctx->current_crl = NULL;
return 1;
}
static int get_crl_sk(X509_STORE_CTX *ctx, X509_CRL **pcrl, X509_CRL **pdcrl,
X509 **pissuer, int *pscore, unsigned int *preasons,
STACK_OF(X509_CRL) *crls)
{
int i, crl_score, best_score = *pscore;
unsigned int reasons, best_reasons = 0;
X509 *x = ctx->current_cert;
X509_CRL *crl, *best_crl = NULL;
X509 *crl_issuer = NULL, *best_crl_issuer = NULL;
for (i = 0; i < sk_X509_CRL_num(crls); i++) {
crl = sk_X509_CRL_value(crls, i);
reasons = *preasons;
crl_score = get_crl_score(ctx, &crl_issuer, &reasons, crl, x);
if (crl_score < best_score || crl_score == 0)
continue;
/* If current CRL is equivalent use it if it is newer */
if (crl_score == best_score && best_crl != NULL) {
int day, sec;
if (ASN1_TIME_diff(&day, &sec, X509_CRL_get0_lastUpdate(best_crl),
X509_CRL_get0_lastUpdate(crl)) == 0)
continue;
/*
* ASN1_TIME_diff never returns inconsistent signs for |day|
* and |sec|.
*/
if (day <= 0 && sec <= 0)
continue;
}
best_crl = crl;
best_crl_issuer = crl_issuer;
best_score = crl_score;
best_reasons = reasons;
}
if (best_crl) {
X509_CRL_free(*pcrl);
*pcrl = best_crl;
*pissuer = best_crl_issuer;
*pscore = best_score;
*preasons = best_reasons;
X509_CRL_up_ref(best_crl);
X509_CRL_free(*pdcrl);
*pdcrl = NULL;
get_delta_sk(ctx, pdcrl, pscore, best_crl, crls);
}
if (best_score >= CRL_SCORE_VALID)
return 1;
return 0;
}
/*
* Compare two CRL extensions for delta checking purposes. They should be
* both present or both absent. If both present all fields must be identical.
*/
static int crl_extension_match(X509_CRL *a, X509_CRL *b, int nid)
{
ASN1_OCTET_STRING *exta, *extb;
int i;
i = X509_CRL_get_ext_by_NID(a, nid, -1);
if (i >= 0) {
/* Can't have multiple occurrences */
if (X509_CRL_get_ext_by_NID(a, nid, i) != -1)
return 0;
exta = X509_EXTENSION_get_data(X509_CRL_get_ext(a, i));
} else
exta = NULL;
i = X509_CRL_get_ext_by_NID(b, nid, -1);
if (i >= 0) {
if (X509_CRL_get_ext_by_NID(b, nid, i) != -1)
return 0;
extb = X509_EXTENSION_get_data(X509_CRL_get_ext(b, i));
} else
extb = NULL;
if (!exta && !extb)
return 1;
if (!exta || !extb)
return 0;
if (ASN1_OCTET_STRING_cmp(exta, extb))
return 0;
return 1;
}
/* See if a base and delta are compatible */
static int check_delta_base(X509_CRL *delta, X509_CRL *base)
{
/* Delta CRL must be a delta */
if (!delta->base_crl_number)
return 0;
/* Base must have a CRL number */
if (!base->crl_number)
return 0;
/* Issuer names must match */
if (X509_NAME_cmp(X509_CRL_get_issuer(base), X509_CRL_get_issuer(delta)))
return 0;
/* AKID and IDP must match */
if (!crl_extension_match(delta, base, NID_authority_key_identifier))
return 0;
if (!crl_extension_match(delta, base, NID_issuing_distribution_point))
return 0;
/* Delta CRL base number must not exceed Full CRL number. */
if (ASN1_INTEGER_cmp(delta->base_crl_number, base->crl_number) > 0)
return 0;
/* Delta CRL number must exceed full CRL number */
if (ASN1_INTEGER_cmp(delta->crl_number, base->crl_number) > 0)
return 1;
return 0;
}
/*
* For a given base CRL find a delta... maybe extend to delta scoring or
* retrieve a chain of deltas...
*/
static void get_delta_sk(X509_STORE_CTX *ctx, X509_CRL **dcrl, int *pscore,
X509_CRL *base, STACK_OF(X509_CRL) *crls)
{
X509_CRL *delta;
int i;
if (!(ctx->param->flags & X509_V_FLAG_USE_DELTAS))
return;
if (!((ctx->current_cert->ex_flags | base->flags) & EXFLAG_FRESHEST))
return;
for (i = 0; i < sk_X509_CRL_num(crls); i++) {
delta = sk_X509_CRL_value(crls, i);
if (check_delta_base(delta, base)) {
if (check_crl_time(ctx, delta, 0))
*pscore |= CRL_SCORE_TIME_DELTA;
X509_CRL_up_ref(delta);
*dcrl = delta;
return;
}
}
*dcrl = NULL;
}
/*
* For a given CRL return how suitable it is for the supplied certificate
* 'x'. The return value is a mask of several criteria. If the issuer is not
* the certificate issuer this is returned in *pissuer. The reasons mask is
* also used to determine if the CRL is suitable: if no new reasons the CRL
* is rejected, otherwise reasons is updated.
*/
static int get_crl_score(X509_STORE_CTX *ctx, X509 **pissuer,
unsigned int *preasons, X509_CRL *crl, X509 *x)
{
int crl_score = 0;
unsigned int tmp_reasons = *preasons, crl_reasons;
/* First see if we can reject CRL straight away */
/* Invalid IDP cannot be processed */
if (crl->idp_flags & IDP_INVALID)
return 0;
/* Reason codes or indirect CRLs need extended CRL support */
if (!(ctx->param->flags & X509_V_FLAG_EXTENDED_CRL_SUPPORT)) {
if (crl->idp_flags & (IDP_INDIRECT | IDP_REASONS))
return 0;
} else if (crl->idp_flags & IDP_REASONS) {
/* If no new reasons reject */
if (!(crl->idp_reasons & ~tmp_reasons))
return 0;
}
/* Don't process deltas at this stage */
else if (crl->base_crl_number)
return 0;
/* If issuer name doesn't match certificate need indirect CRL */
if (X509_NAME_cmp(X509_get_issuer_name(x), X509_CRL_get_issuer(crl))) {
if (!(crl->idp_flags & IDP_INDIRECT))
return 0;
} else
crl_score |= CRL_SCORE_ISSUER_NAME;
if (!(crl->flags & EXFLAG_CRITICAL))
crl_score |= CRL_SCORE_NOCRITICAL;
/* Check expiry */
if (check_crl_time(ctx, crl, 0))
crl_score |= CRL_SCORE_TIME;
/* Check authority key ID and locate certificate issuer */
crl_akid_check(ctx, crl, pissuer, &crl_score);
/* If we can't locate certificate issuer at this point forget it */
if (!(crl_score & CRL_SCORE_AKID))
return 0;
/* Check cert for matching CRL distribution points */
if (crl_crldp_check(x, crl, crl_score, &crl_reasons)) {
/* If no new reasons reject */
if (!(crl_reasons & ~tmp_reasons))
return 0;
tmp_reasons |= crl_reasons;
crl_score |= CRL_SCORE_SCOPE;
}
*preasons = tmp_reasons;
return crl_score;
}
static void crl_akid_check(X509_STORE_CTX *ctx, X509_CRL *crl,
X509 **pissuer, int *pcrl_score)
{
X509 *crl_issuer = NULL;
X509_NAME *cnm = X509_CRL_get_issuer(crl);
int cidx = ctx->error_depth;
int i;
if (cidx != sk_X509_num(ctx->chain) - 1)
cidx++;
crl_issuer = sk_X509_value(ctx->chain, cidx);
if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK) {
if (*pcrl_score & CRL_SCORE_ISSUER_NAME) {
*pcrl_score |= CRL_SCORE_AKID | CRL_SCORE_ISSUER_CERT;
*pissuer = crl_issuer;
return;
}
}
for (cidx++; cidx < sk_X509_num(ctx->chain); cidx++) {
crl_issuer = sk_X509_value(ctx->chain, cidx);
if (X509_NAME_cmp(X509_get_subject_name(crl_issuer), cnm))
continue;
if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK) {
*pcrl_score |= CRL_SCORE_AKID | CRL_SCORE_SAME_PATH;
*pissuer = crl_issuer;
return;
}
}
/* Anything else needs extended CRL support */
if (!(ctx->param->flags & X509_V_FLAG_EXTENDED_CRL_SUPPORT))
return;
/*
* Otherwise the CRL issuer is not on the path. Look for it in the set of
* untrusted certificates.
*/
for (i = 0; i < sk_X509_num(ctx->untrusted); i++) {
crl_issuer = sk_X509_value(ctx->untrusted, i);
if (X509_NAME_cmp(X509_get_subject_name(crl_issuer), cnm))
continue;
if (X509_check_akid(crl_issuer, crl->akid) == X509_V_OK) {
*pissuer = crl_issuer;
*pcrl_score |= CRL_SCORE_AKID;
return;
}
}
}
/*
* Check the path of a CRL issuer certificate. This creates a new
* X509_STORE_CTX and populates it with most of the parameters from the
* parent. This could be optimised somewhat since a lot of path checking will
* be duplicated by the parent, but this will rarely be used in practice.
*/
static int check_crl_path(X509_STORE_CTX *ctx, X509 *x)
{
X509_STORE_CTX crl_ctx;
int ret;
/* Don't allow recursive CRL path validation */
if (ctx->parent)
return 0;
if (!X509_STORE_CTX_init(&crl_ctx, ctx->ctx, x, ctx->untrusted))
return -1;
crl_ctx.crls = ctx->crls;
/* Copy verify params across */
X509_STORE_CTX_set0_param(&crl_ctx, ctx->param);
crl_ctx.parent = ctx;
crl_ctx.verify_cb = ctx->verify_cb;
/* Verify CRL issuer */
ret = X509_verify_cert(&crl_ctx);
if (ret <= 0)
goto err;
/* Check chain is acceptable */
ret = check_crl_chain(ctx, ctx->chain, crl_ctx.chain);
err:
X509_STORE_CTX_cleanup(&crl_ctx);
return ret;
}
/*
* RFC3280 says nothing about the relationship between CRL path and
* certificate path, which could lead to situations where a certificate could
* be revoked or validated by a CA not authorised to do so. RFC5280 is more
* strict and states that the two paths must end in the same trust anchor,
* though some discussions remain... until this is resolved we use the
* RFC5280 version
*/
static int check_crl_chain(X509_STORE_CTX *ctx,
STACK_OF(X509) *cert_path,
STACK_OF(X509) *crl_path)
{
X509 *cert_ta, *crl_ta;
cert_ta = sk_X509_value(cert_path, sk_X509_num(cert_path) - 1);
crl_ta = sk_X509_value(crl_path, sk_X509_num(crl_path) - 1);
if (!X509_cmp(cert_ta, crl_ta))
return 1;
return 0;
}
/*-
* Check for match between two dist point names: three separate cases.
* 1. Both are relative names and compare X509_NAME types.
* 2. One full, one relative. Compare X509_NAME to GENERAL_NAMES.
* 3. Both are full names and compare two GENERAL_NAMES.
* 4. One is NULL: automatic match.
*/
static int idp_check_dp(DIST_POINT_NAME *a, DIST_POINT_NAME *b)
{
X509_NAME *nm = NULL;
GENERAL_NAMES *gens = NULL;
GENERAL_NAME *gena, *genb;
int i, j;
if (!a || !b)
return 1;
if (a->type == 1) {
if (!a->dpname)
return 0;
/* Case 1: two X509_NAME */
if (b->type == 1) {
if (!b->dpname)
return 0;
if (!X509_NAME_cmp(a->dpname, b->dpname))
return 1;
else
return 0;
}
/* Case 2: set name and GENERAL_NAMES appropriately */
nm = a->dpname;
gens = b->name.fullname;
} else if (b->type == 1) {
if (!b->dpname)
return 0;
/* Case 2: set name and GENERAL_NAMES appropriately */
gens = a->name.fullname;
nm = b->dpname;
}
/* Handle case 2 with one GENERAL_NAMES and one X509_NAME */
if (nm) {
for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
gena = sk_GENERAL_NAME_value(gens, i);
if (gena->type != GEN_DIRNAME)
continue;
if (!X509_NAME_cmp(nm, gena->d.directoryName))
return 1;
}
return 0;
}
/* Else case 3: two GENERAL_NAMES */
for (i = 0; i < sk_GENERAL_NAME_num(a->name.fullname); i++) {
gena = sk_GENERAL_NAME_value(a->name.fullname, i);
for (j = 0; j < sk_GENERAL_NAME_num(b->name.fullname); j++) {
genb = sk_GENERAL_NAME_value(b->name.fullname, j);
if (!GENERAL_NAME_cmp(gena, genb))
return 1;
}
}
return 0;
}
static int crldp_check_crlissuer(DIST_POINT *dp, X509_CRL *crl, int crl_score)
{
int i;
X509_NAME *nm = X509_CRL_get_issuer(crl);
/* If no CRLissuer return is successful iff don't need a match */
if (!dp->CRLissuer)
return ! !(crl_score & CRL_SCORE_ISSUER_NAME);
for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
if (gen->type != GEN_DIRNAME)
continue;
if (!X509_NAME_cmp(gen->d.directoryName, nm))
return 1;
}
return 0;
}
/* Check CRLDP and IDP */
static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
unsigned int *preasons)
{
int i;
if (crl->idp_flags & IDP_ONLYATTR)
return 0;
if (x->ex_flags & EXFLAG_CA) {
if (crl->idp_flags & IDP_ONLYUSER)
return 0;
} else {
if (crl->idp_flags & IDP_ONLYCA)
return 0;
}
*preasons = crl->idp_reasons;
for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) {
DIST_POINT *dp = sk_DIST_POINT_value(x->crldp, i);
if (crldp_check_crlissuer(dp, crl, crl_score)) {
if (!crl->idp || idp_check_dp(dp->distpoint, crl->idp->distpoint)) {
*preasons &= dp->dp_reasons;
return 1;
}
}
}
if ((!crl->idp || !crl->idp->distpoint)
&& (crl_score & CRL_SCORE_ISSUER_NAME))
return 1;
return 0;
}
/*
* Retrieve CRL corresponding to current certificate. If deltas enabled try
* to find a delta CRL too
*/
static int get_crl_delta(X509_STORE_CTX *ctx,
X509_CRL **pcrl, X509_CRL **pdcrl, X509 *x)
{
int ok;
X509 *issuer = NULL;
int crl_score = 0;
unsigned int reasons;
X509_CRL *crl = NULL, *dcrl = NULL;
STACK_OF(X509_CRL) *skcrl;
X509_NAME *nm = X509_get_issuer_name(x);
reasons = ctx->current_reasons;
ok = get_crl_sk(ctx, &crl, &dcrl,
&issuer, &crl_score, &reasons, ctx->crls);
if (ok)
goto done;
/* Lookup CRLs from store */
skcrl = ctx->lookup_crls(ctx, nm);
/* If no CRLs found and a near match from get_crl_sk use that */
if (!skcrl && crl)
goto done;
get_crl_sk(ctx, &crl, &dcrl, &issuer, &crl_score, &reasons, skcrl);
sk_X509_CRL_pop_free(skcrl, X509_CRL_free);
done:
/* If we got any kind of CRL use it and return success */
if (crl) {
ctx->current_issuer = issuer;
ctx->current_crl_score = crl_score;
ctx->current_reasons = reasons;
*pcrl = crl;
*pdcrl = dcrl;
return 1;
}
return 0;
}
/* Check CRL validity */
static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
{
X509 *issuer = NULL;
EVP_PKEY *ikey = NULL;
int cnum = ctx->error_depth;
int chnum = sk_X509_num(ctx->chain) - 1;
/* if we have an alternative CRL issuer cert use that */
if (ctx->current_issuer)
issuer = ctx->current_issuer;
/*
* Else find CRL issuer: if not last certificate then issuer is next
* certificate in chain.
*/
else if (cnum < chnum)
issuer = sk_X509_value(ctx->chain, cnum + 1);
else {
issuer = sk_X509_value(ctx->chain, chnum);
/* If not self signed, can't check signature */
if (!ctx->check_issued(ctx, issuer, issuer) &&
!verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER))
return 0;
}
if (issuer == NULL)
return 1;
/*
* Skip most tests for deltas because they have already been done
*/
if (!crl->base_crl_number) {
/* Check for cRLSign bit if keyUsage present */
if ((issuer->ex_flags & EXFLAG_KUSAGE) &&
!(issuer->ex_kusage & KU_CRL_SIGN) &&
!verify_cb_crl(ctx, X509_V_ERR_KEYUSAGE_NO_CRL_SIGN))
return 0;
if (!(ctx->current_crl_score & CRL_SCORE_SCOPE) &&
!verify_cb_crl(ctx, X509_V_ERR_DIFFERENT_CRL_SCOPE))
return 0;
if (!(ctx->current_crl_score & CRL_SCORE_SAME_PATH) &&
check_crl_path(ctx, ctx->current_issuer) <= 0 &&
!verify_cb_crl(ctx, X509_V_ERR_CRL_PATH_VALIDATION_ERROR))
return 0;
if ((crl->idp_flags & IDP_INVALID) &&
!verify_cb_crl(ctx, X509_V_ERR_INVALID_EXTENSION))
return 0;
}
if (!(ctx->current_crl_score & CRL_SCORE_TIME) &&
!check_crl_time(ctx, crl, 1))
return 0;
/* Attempt to get issuer certificate public key */
ikey = X509_get0_pubkey(issuer);
if (!ikey &&
!verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY))
return 0;
if (ikey) {
int rv = X509_CRL_check_suiteb(crl, ikey, ctx->param->flags);
if (rv != X509_V_OK && !verify_cb_crl(ctx, rv))
return 0;
/* Verify CRL signature */
if (X509_CRL_verify(crl, ikey) <= 0 &&
!verify_cb_crl(ctx, X509_V_ERR_CRL_SIGNATURE_FAILURE))
return 0;
}
return 1;
}
/* Check certificate against CRL */
static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
{
X509_REVOKED *rev;
/*
* The rules changed for this... previously if a CRL contained unhandled
* critical extensions it could still be used to indicate a certificate
* was revoked. This has since been changed since critical extensions can
* change the meaning of CRL entries.
*/
if (!(ctx->param->flags & X509_V_FLAG_IGNORE_CRITICAL)
&& (crl->flags & EXFLAG_CRITICAL) &&
!verify_cb_crl(ctx, X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION))
return 0;
/*
* Look for serial number of certificate in CRL. If found, make sure
* reason is not removeFromCRL.
*/
if (X509_CRL_get0_by_cert(crl, &rev, x)) {
if (rev->reason == CRL_REASON_REMOVE_FROM_CRL)
return 2;
if (!verify_cb_crl(ctx, X509_V_ERR_CERT_REVOKED))
return 0;
}
return 1;
}
static int check_policy(X509_STORE_CTX *ctx)
{
int ret;
if (ctx->parent)
return 1;
/*
* With DANE, the trust anchor might be a bare public key, not a
* certificate! In that case our chain does not have the trust anchor
* certificate as a top-most element. This comports well with RFC5280
* chain verification, since there too, the trust anchor is not part of the
* chain to be verified. In particular, X509_policy_check() does not look
* at the TA cert, but assumes that it is present as the top-most chain
* element. We therefore temporarily push a NULL cert onto the chain if it
* was verified via a bare public key, and pop it off right after the
* X509_policy_check() call.
*/
if (ctx->bare_ta_signed && !sk_X509_push(ctx->chain, NULL)) {
X509err(X509_F_CHECK_POLICY, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
ret = X509_policy_check(&ctx->tree, &ctx->explicit_policy, ctx->chain,
ctx->param->policies, ctx->param->flags);
if (ctx->bare_ta_signed)
sk_X509_pop(ctx->chain);
if (ret == X509_PCY_TREE_INTERNAL) {
X509err(X509_F_CHECK_POLICY, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
/* Invalid or inconsistent extensions */
if (ret == X509_PCY_TREE_INVALID) {
int i;
/* Locate certificates with bad extensions and notify callback. */
for (i = 1; i < sk_X509_num(ctx->chain); i++) {
X509 *x = sk_X509_value(ctx->chain, i);
if (!(x->ex_flags & EXFLAG_INVALID_POLICY))
continue;
if (!verify_cb_cert(ctx, x, i,
X509_V_ERR_INVALID_POLICY_EXTENSION))
return 0;
}
return 1;
}
if (ret == X509_PCY_TREE_FAILURE) {
ctx->current_cert = NULL;
ctx->error = X509_V_ERR_NO_EXPLICIT_POLICY;
return ctx->verify_cb(0, ctx);
}
if (ret != X509_PCY_TREE_VALID) {
X509err(X509_F_CHECK_POLICY, ERR_R_INTERNAL_ERROR);
return 0;
}
if (ctx->param->flags & X509_V_FLAG_NOTIFY_POLICY) {
ctx->current_cert = NULL;
/*
* Verification errors need to be "sticky", a callback may have allowed
* an SSL handshake to continue despite an error, and we must then
* remain in an error state. Therefore, we MUST NOT clear earlier
* verification errors by setting the error to X509_V_OK.
*/
if (!ctx->verify_cb(2, ctx))
return 0;
}
return 1;
}
/*-
* Check certificate validity times.
* If depth >= 0, invoke verification callbacks on error, otherwise just return
* the validation status.
*
* Return 1 on success, 0 otherwise.
*/
int x509_check_cert_time(X509_STORE_CTX *ctx, X509 *x, int depth)
{
time_t *ptime;
int i;
if (ctx->param->flags & X509_V_FLAG_USE_CHECK_TIME)
ptime = &ctx->param->check_time;
else if (ctx->param->flags & X509_V_FLAG_NO_CHECK_TIME)
return 1;
else
ptime = NULL;
i = X509_cmp_time(X509_get0_notBefore(x), ptime);
if (i >= 0 && depth < 0)
return 0;
if (i == 0 && !verify_cb_cert(ctx, x, depth,
X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD))
return 0;
if (i > 0 && !verify_cb_cert(ctx, x, depth, X509_V_ERR_CERT_NOT_YET_VALID))
return 0;
i = X509_cmp_time(X509_get0_notAfter(x), ptime);
if (i <= 0 && depth < 0)
return 0;
if (i == 0 && !verify_cb_cert(ctx, x, depth,
X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD))
return 0;
if (i < 0 && !verify_cb_cert(ctx, x, depth, X509_V_ERR_CERT_HAS_EXPIRED))
return 0;
return 1;
}
static int internal_verify(X509_STORE_CTX *ctx)
{
int n = sk_X509_num(ctx->chain) - 1;
X509 *xi = sk_X509_value(ctx->chain, n);
X509 *xs;
/*
* With DANE-verified bare public key TA signatures, it remains only to
* check the timestamps of the top certificate. We report the issuer as
* NULL, since all we have is a bare key.
*/
if (ctx->bare_ta_signed) {
xs = xi;
xi = NULL;
goto check_cert;
}
if (ctx->check_issued(ctx, xi, xi))
xs = xi;
else {
if (ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN) {
xs = xi;
goto check_cert;
}
if (n <= 0)
return verify_cb_cert(ctx, xi, 0,
X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE);
n--;
ctx->error_depth = n;
xs = sk_X509_value(ctx->chain, n);
}
/*
* Do not clear ctx->error=0, it must be "sticky", only the user's callback
* is allowed to reset errors (at its own peril).
*/
while (n >= 0) {
EVP_PKEY *pkey;
/*
* Skip signature check for self signed certificates unless explicitly
* asked for. It doesn't add any security and just wastes time. If
* the issuer's public key is unusable, report the issuer certificate
* and its depth (rather than the depth of the subject).
*/
if (xs != xi || (ctx->param->flags & X509_V_FLAG_CHECK_SS_SIGNATURE)) {
if ((pkey = X509_get0_pubkey(xi)) == NULL) {
if (!verify_cb_cert(ctx, xi, xi != xs ? n+1 : n,
X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY))
return 0;
} else if (X509_verify(xs, pkey) <= 0) {
if (!verify_cb_cert(ctx, xs, n,
X509_V_ERR_CERT_SIGNATURE_FAILURE))
return 0;
}
}
check_cert:
/* Calls verify callback as needed */
if (!x509_check_cert_time(ctx, xs, n))
return 0;
/*
* Signal success at this depth. However, the previous error (if any)
* is retained.
*/
ctx->current_issuer = xi;
ctx->current_cert = xs;
ctx->error_depth = n;
if (!ctx->verify_cb(1, ctx))
return 0;
if (--n >= 0) {
xi = xs;
xs = sk_X509_value(ctx->chain, n);
}
}
return 1;
}
int X509_cmp_current_time(const ASN1_TIME *ctm)
{
return X509_cmp_time(ctm, NULL);
}
int X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
{
static const size_t utctime_length = sizeof("YYMMDDHHMMSSZ") - 1;
static const size_t generalizedtime_length = sizeof("YYYYMMDDHHMMSSZ") - 1;
ASN1_TIME *asn1_cmp_time = NULL;
int i, day, sec, ret = 0;
/*
* Note that ASN.1 allows much more slack in the time format than RFC5280.
* In RFC5280, the representation is fixed:
* UTCTime: YYMMDDHHMMSSZ
* GeneralizedTime: YYYYMMDDHHMMSSZ
*
* We do NOT currently enforce the following RFC 5280 requirement:
* "CAs conforming to this profile MUST always encode certificate
* validity dates through the year 2049 as UTCTime; certificate validity
* dates in 2050 or later MUST be encoded as GeneralizedTime."
*/
switch (ctm->type) {
case V_ASN1_UTCTIME:
if (ctm->length != (int)(utctime_length))
return 0;
break;
case V_ASN1_GENERALIZEDTIME:
if (ctm->length != (int)(generalizedtime_length))
return 0;
break;
default:
return 0;
}
/**
* Verify the format: the ASN.1 functions we use below allow a more
* flexible format than what's mandated by RFC 5280.
* Digit and date ranges will be verified in the conversion methods.
*/
for (i = 0; i < ctm->length - 1; i++) {
if (!ossl_isdigit(ctm->data[i]))
return 0;
}
if (ctm->data[ctm->length - 1] != 'Z')
return 0;
/*
* There is ASN1_UTCTIME_cmp_time_t but no
* ASN1_GENERALIZEDTIME_cmp_time_t or ASN1_TIME_cmp_time_t,
* so we go through ASN.1
*/
asn1_cmp_time = X509_time_adj(NULL, 0, cmp_time);
if (asn1_cmp_time == NULL)
goto err;
if (!ASN1_TIME_diff(&day, &sec, ctm, asn1_cmp_time))
goto err;
/*
* X509_cmp_time comparison is <=.
* The return value 0 is reserved for errors.
*/
ret = (day >= 0 && sec >= 0) ? -1 : 1;
err:
ASN1_TIME_free(asn1_cmp_time);
return ret;
}
ASN1_TIME *X509_gmtime_adj(ASN1_TIME *s, long adj)
{
return X509_time_adj(s, adj, NULL);
}
ASN1_TIME *X509_time_adj(ASN1_TIME *s, long offset_sec, time_t *in_tm)
{
return X509_time_adj_ex(s, 0, offset_sec, in_tm);
}
ASN1_TIME *X509_time_adj_ex(ASN1_TIME *s,
int offset_day, long offset_sec, time_t *in_tm)
{
time_t t;
if (in_tm)
t = *in_tm;
else
time(&t);
if (s && !(s->flags & ASN1_STRING_FLAG_MSTRING)) {
if (s->type == V_ASN1_UTCTIME)
return ASN1_UTCTIME_adj(s, t, offset_day, offset_sec);
if (s->type == V_ASN1_GENERALIZEDTIME)
return ASN1_GENERALIZEDTIME_adj(s, t, offset_day, offset_sec);
}
return ASN1_TIME_adj(s, t, offset_day, offset_sec);
}
int X509_get_pubkey_parameters(EVP_PKEY *pkey, STACK_OF(X509) *chain)
{
EVP_PKEY *ktmp = NULL, *ktmp2;
int i, j;
if ((pkey != NULL) && !EVP_PKEY_missing_parameters(pkey))
return 1;
for (i = 0; i < sk_X509_num(chain); i++) {
ktmp = X509_get0_pubkey(sk_X509_value(chain, i));
if (ktmp == NULL) {
X509err(X509_F_X509_GET_PUBKEY_PARAMETERS,
X509_R_UNABLE_TO_GET_CERTS_PUBLIC_KEY);
return 0;
}
if (!EVP_PKEY_missing_parameters(ktmp))
break;
}
if (ktmp == NULL) {
X509err(X509_F_X509_GET_PUBKEY_PARAMETERS,
X509_R_UNABLE_TO_FIND_PARAMETERS_IN_CHAIN);
return 0;
}
/* first, populate the other certs */
for (j = i - 1; j >= 0; j--) {
ktmp2 = X509_get0_pubkey(sk_X509_value(chain, j));
EVP_PKEY_copy_parameters(ktmp2, ktmp);
}
if (pkey != NULL)
EVP_PKEY_copy_parameters(pkey, ktmp);
return 1;
}
/* Make a delta CRL as the diff between two full CRLs */
X509_CRL *X509_CRL_diff(X509_CRL *base, X509_CRL *newer,
EVP_PKEY *skey, const EVP_MD *md, unsigned int flags)
{
X509_CRL *crl = NULL;
int i;
STACK_OF(X509_REVOKED) *revs = NULL;
/* CRLs can't be delta already */
if (base->base_crl_number || newer->base_crl_number) {
X509err(X509_F_X509_CRL_DIFF, X509_R_CRL_ALREADY_DELTA);
return NULL;
}
/* Base and new CRL must have a CRL number */
if (!base->crl_number || !newer->crl_number) {
X509err(X509_F_X509_CRL_DIFF, X509_R_NO_CRL_NUMBER);
return NULL;
}
/* Issuer names must match */
if (X509_NAME_cmp(X509_CRL_get_issuer(base), X509_CRL_get_issuer(newer))) {
X509err(X509_F_X509_CRL_DIFF, X509_R_ISSUER_MISMATCH);
return NULL;
}
/* AKID and IDP must match */
if (!crl_extension_match(base, newer, NID_authority_key_identifier)) {
X509err(X509_F_X509_CRL_DIFF, X509_R_AKID_MISMATCH);
return NULL;
}
if (!crl_extension_match(base, newer, NID_issuing_distribution_point)) {
X509err(X509_F_X509_CRL_DIFF, X509_R_IDP_MISMATCH);
return NULL;
}
/* Newer CRL number must exceed full CRL number */
if (ASN1_INTEGER_cmp(newer->crl_number, base->crl_number) <= 0) {
X509err(X509_F_X509_CRL_DIFF, X509_R_NEWER_CRL_NOT_NEWER);
return NULL;
}
/* CRLs must verify */
if (skey && (X509_CRL_verify(base, skey) <= 0 ||
X509_CRL_verify(newer, skey) <= 0)) {
X509err(X509_F_X509_CRL_DIFF, X509_R_CRL_VERIFY_FAILURE);
return NULL;
}
/* Create new CRL */
crl = X509_CRL_new();
if (crl == NULL || !X509_CRL_set_version(crl, 1))
goto memerr;
/* Set issuer name */
if (!X509_CRL_set_issuer_name(crl, X509_CRL_get_issuer(newer)))
goto memerr;
if (!X509_CRL_set1_lastUpdate(crl, X509_CRL_get0_lastUpdate(newer)))
goto memerr;
if (!X509_CRL_set1_nextUpdate(crl, X509_CRL_get0_nextUpdate(newer)))
goto memerr;
/* Set base CRL number: must be critical */
if (!X509_CRL_add1_ext_i2d(crl, NID_delta_crl, base->crl_number, 1, 0))
goto memerr;
/*
* Copy extensions across from newest CRL to delta: this will set CRL
* number to correct value too.
*/
for (i = 0; i < X509_CRL_get_ext_count(newer); i++) {
X509_EXTENSION *ext;
ext = X509_CRL_get_ext(newer, i);
if (!X509_CRL_add_ext(crl, ext, -1))
goto memerr;
}
/* Go through revoked entries, copying as needed */
revs = X509_CRL_get_REVOKED(newer);
for (i = 0; i < sk_X509_REVOKED_num(revs); i++) {
X509_REVOKED *rvn, *rvtmp;
rvn = sk_X509_REVOKED_value(revs, i);
/*
* Add only if not also in base. TODO: need something cleverer here
* for some more complex CRLs covering multiple CAs.
*/
if (!X509_CRL_get0_by_serial(base, &rvtmp, &rvn->serialNumber)) {
rvtmp = X509_REVOKED_dup(rvn);
if (!rvtmp)
goto memerr;
if (!X509_CRL_add0_revoked(crl, rvtmp)) {
X509_REVOKED_free(rvtmp);
goto memerr;
}
}
}
/* TODO: optionally prune deleted entries */
if (skey && md && !X509_CRL_sign(crl, skey, md))
goto memerr;
return crl;
memerr:
X509err(X509_F_X509_CRL_DIFF, ERR_R_MALLOC_FAILURE);
X509_CRL_free(crl);
return NULL;
}
int X509_STORE_CTX_set_ex_data(X509_STORE_CTX *ctx, int idx, void *data)
{
return CRYPTO_set_ex_data(&ctx->ex_data, idx, data);
}
void *X509_STORE_CTX_get_ex_data(X509_STORE_CTX *ctx, int idx)
{
return CRYPTO_get_ex_data(&ctx->ex_data, idx);
}
int X509_STORE_CTX_get_error(X509_STORE_CTX *ctx)
{
return ctx->error;
}
void X509_STORE_CTX_set_error(X509_STORE_CTX *ctx, int err)
{
ctx->error = err;
}
int X509_STORE_CTX_get_error_depth(X509_STORE_CTX *ctx)
{
return ctx->error_depth;
}
void X509_STORE_CTX_set_error_depth(X509_STORE_CTX *ctx, int depth)
{
ctx->error_depth = depth;
}
X509 *X509_STORE_CTX_get_current_cert(X509_STORE_CTX *ctx)
{
return ctx->current_cert;
}
void X509_STORE_CTX_set_current_cert(X509_STORE_CTX *ctx, X509 *x)
{
ctx->current_cert = x;
}
STACK_OF(X509) *X509_STORE_CTX_get0_chain(X509_STORE_CTX *ctx)
{
return ctx->chain;
}
STACK_OF(X509) *X509_STORE_CTX_get1_chain(X509_STORE_CTX *ctx)
{
if (!ctx->chain)
return NULL;
return X509_chain_up_ref(ctx->chain);
}
X509 *X509_STORE_CTX_get0_current_issuer(X509_STORE_CTX *ctx)
{
return ctx->current_issuer;
}
X509_CRL *X509_STORE_CTX_get0_current_crl(X509_STORE_CTX *ctx)
{
return ctx->current_crl;
}
X509_STORE_CTX *X509_STORE_CTX_get0_parent_ctx(X509_STORE_CTX *ctx)
{
return ctx->parent;
}
void X509_STORE_CTX_set_cert(X509_STORE_CTX *ctx, X509 *x)
{
ctx->cert = x;
}
void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx, STACK_OF(X509_CRL) *sk)
{
ctx->crls = sk;
}
int X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose)
{
/*
* XXX: Why isn't this function always used to set the associated trust?
* Should there even be a VPM->trust field at all? Or should the trust
* always be inferred from the purpose by X509_STORE_CTX_init().
*/
return X509_STORE_CTX_purpose_inherit(ctx, 0, purpose, 0);
}
int X509_STORE_CTX_set_trust(X509_STORE_CTX *ctx, int trust)
{
/*
* XXX: See above, this function would only be needed when the default
* trust for the purpose needs an override in a corner case.
*/
return X509_STORE_CTX_purpose_inherit(ctx, 0, 0, trust);
}
/*
* This function is used to set the X509_STORE_CTX purpose and trust values.
* This is intended to be used when another structure has its own trust and
* purpose values which (if set) will be inherited by the ctx. If they aren't
* set then we will usually have a default purpose in mind which should then
* be used to set the trust value. An example of this is SSL use: an SSL
* structure will have its own purpose and trust settings which the
* application can set: if they aren't set then we use the default of SSL
* client/server.
*/
int X509_STORE_CTX_purpose_inherit(X509_STORE_CTX *ctx, int def_purpose,
int purpose, int trust)
{
int idx;
/* If purpose not set use default */
if (!purpose)
purpose = def_purpose;
/* If we have a purpose then check it is valid */
if (purpose) {
X509_PURPOSE *ptmp;
idx = X509_PURPOSE_get_by_id(purpose);
if (idx == -1) {
X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
X509_R_UNKNOWN_PURPOSE_ID);
return 0;
}
ptmp = X509_PURPOSE_get0(idx);
if (ptmp->trust == X509_TRUST_DEFAULT) {
idx = X509_PURPOSE_get_by_id(def_purpose);
/*
* XXX: In the two callers above def_purpose is always 0, which is
* not a known value, so idx will always be -1. How is the
* X509_TRUST_DEFAULT case actually supposed to be handled?
*/
if (idx == -1) {
X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
X509_R_UNKNOWN_PURPOSE_ID);
return 0;
}
ptmp = X509_PURPOSE_get0(idx);
}
/* If trust not set then get from purpose default */
if (!trust)
trust = ptmp->trust;
}
if (trust) {
idx = X509_TRUST_get_by_id(trust);
if (idx == -1) {
X509err(X509_F_X509_STORE_CTX_PURPOSE_INHERIT,
X509_R_UNKNOWN_TRUST_ID);
return 0;
}
}
if (purpose && !ctx->param->purpose)
ctx->param->purpose = purpose;
if (trust && !ctx->param->trust)
ctx->param->trust = trust;
return 1;
}
X509_STORE_CTX *X509_STORE_CTX_new(void)
{
X509_STORE_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
if (ctx == NULL) {
X509err(X509_F_X509_STORE_CTX_NEW, ERR_R_MALLOC_FAILURE);
return NULL;
}
return ctx;
}
void X509_STORE_CTX_free(X509_STORE_CTX *ctx)
{
if (ctx == NULL)
return;
X509_STORE_CTX_cleanup(ctx);
OPENSSL_free(ctx);
}
int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
STACK_OF(X509) *chain)
{
int ret = 1;
ctx->ctx = store;
ctx->cert = x509;
ctx->untrusted = chain;
ctx->crls = NULL;
ctx->num_untrusted = 0;
ctx->other_ctx = NULL;
ctx->valid = 0;
ctx->chain = NULL;
ctx->error = 0;
ctx->explicit_policy = 0;
ctx->error_depth = 0;
ctx->current_cert = NULL;
ctx->current_issuer = NULL;
ctx->current_crl = NULL;
ctx->current_crl_score = 0;
ctx->current_reasons = 0;
ctx->tree = NULL;
ctx->parent = NULL;
ctx->dane = NULL;
ctx->bare_ta_signed = 0;
/* Zero ex_data to make sure we're cleanup-safe */
memset(&ctx->ex_data, 0, sizeof(ctx->ex_data));
/* store->cleanup is always 0 in OpenSSL, if set must be idempotent */
if (store)
ctx->cleanup = store->cleanup;
else
ctx->cleanup = 0;
if (store && store->check_issued)
ctx->check_issued = store->check_issued;
else
ctx->check_issued = check_issued;
if (store && store->get_issuer)
ctx->get_issuer = store->get_issuer;
else
ctx->get_issuer = X509_STORE_CTX_get1_issuer;
if (store && store->verify_cb)
ctx->verify_cb = store->verify_cb;
else
ctx->verify_cb = null_callback;
if (store && store->verify)
ctx->verify = store->verify;
else
ctx->verify = internal_verify;
if (store && store->check_revocation)
ctx->check_revocation = store->check_revocation;
else
ctx->check_revocation = check_revocation;
if (store && store->get_crl)
ctx->get_crl = store->get_crl;
else
ctx->get_crl = NULL;
if (store && store->check_crl)
ctx->check_crl = store->check_crl;
else
ctx->check_crl = check_crl;
if (store && store->cert_crl)
ctx->cert_crl = store->cert_crl;
else
ctx->cert_crl = cert_crl;
if (store && store->check_policy)
ctx->check_policy = store->check_policy;
else
ctx->check_policy = check_policy;
if (store && store->lookup_certs)
ctx->lookup_certs = store->lookup_certs;
else
ctx->lookup_certs = X509_STORE_CTX_get1_certs;
if (store && store->lookup_crls)
ctx->lookup_crls = store->lookup_crls;
else
ctx->lookup_crls = X509_STORE_CTX_get1_crls;
ctx->param = X509_VERIFY_PARAM_new();
if (ctx->param == NULL) {
X509err(X509_F_X509_STORE_CTX_INIT, ERR_R_MALLOC_FAILURE);
goto err;
}
/*
* Inherit callbacks and flags from X509_STORE if not set use defaults.
*/
if (store)
ret = X509_VERIFY_PARAM_inherit(ctx->param, store->param);
else
ctx->param->inh_flags |= X509_VP_FLAG_DEFAULT | X509_VP_FLAG_ONCE;
if (ret)
ret = X509_VERIFY_PARAM_inherit(ctx->param,
X509_VERIFY_PARAM_lookup("default"));
if (ret == 0) {
X509err(X509_F_X509_STORE_CTX_INIT, ERR_R_MALLOC_FAILURE);
goto err;
}
/*
* XXX: For now, continue to inherit trust from VPM, but infer from the
* purpose if this still yields the default value.
*/
if (ctx->param->trust == X509_TRUST_DEFAULT) {
int idx = X509_PURPOSE_get_by_id(ctx->param->purpose);
X509_PURPOSE *xp = X509_PURPOSE_get0(idx);
if (xp != NULL)
ctx->param->trust = X509_PURPOSE_get_trust(xp);
}
if (CRYPTO_new_ex_data(CRYPTO_EX_INDEX_X509_STORE_CTX, ctx,
&ctx->ex_data))
return 1;
X509err(X509_F_X509_STORE_CTX_INIT, ERR_R_MALLOC_FAILURE);
err:
/*
* On error clean up allocated storage, if the store context was not
* allocated with X509_STORE_CTX_new() this is our last chance to do so.
*/
X509_STORE_CTX_cleanup(ctx);
return 0;
}
/*
* Set alternative lookup method: just a STACK of trusted certificates. This
* avoids X509_STORE nastiness where it isn't needed.
*/
void X509_STORE_CTX_set0_trusted_stack(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
{
ctx->other_ctx = sk;
ctx->get_issuer = get_issuer_sk;
ctx->lookup_certs = lookup_certs_sk;
}
void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx)
{
/*
* We need to be idempotent because, unfortunately, free() also calls
* cleanup(), so the natural call sequence new(), init(), cleanup(), free()
* calls cleanup() for the same object twice! Thus we must zero the
* pointers below after they're freed!
*/
/* Seems to always be 0 in OpenSSL, do this at most once. */
if (ctx->cleanup != NULL) {
ctx->cleanup(ctx);
ctx->cleanup = NULL;
}
if (ctx->param != NULL) {
if (ctx->parent == NULL)
X509_VERIFY_PARAM_free(ctx->param);
ctx->param = NULL;
}
X509_policy_tree_free(ctx->tree);
ctx->tree = NULL;
sk_X509_pop_free(ctx->chain, X509_free);
ctx->chain = NULL;
CRYPTO_free_ex_data(CRYPTO_EX_INDEX_X509_STORE_CTX, ctx, &(ctx->ex_data));
memset(&ctx->ex_data, 0, sizeof(ctx->ex_data));
}
void X509_STORE_CTX_set_depth(X509_STORE_CTX *ctx, int depth)
{
X509_VERIFY_PARAM_set_depth(ctx->param, depth);
}
void X509_STORE_CTX_set_flags(X509_STORE_CTX *ctx, unsigned long flags)
{
X509_VERIFY_PARAM_set_flags(ctx->param, flags);
}
void X509_STORE_CTX_set_time(X509_STORE_CTX *ctx, unsigned long flags,
time_t t)
{
X509_VERIFY_PARAM_set_time(ctx->param, t);
}
X509 *X509_STORE_CTX_get0_cert(X509_STORE_CTX *ctx)
{
return ctx->cert;
}
STACK_OF(X509) *X509_STORE_CTX_get0_untrusted(X509_STORE_CTX *ctx)
{
return ctx->untrusted;
}
void X509_STORE_CTX_set0_untrusted(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
{
ctx->untrusted = sk;
}
void X509_STORE_CTX_set0_verified_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *sk)
{
sk_X509_pop_free(ctx->chain, X509_free);
ctx->chain = sk;
}
void X509_STORE_CTX_set_verify_cb(X509_STORE_CTX *ctx,
X509_STORE_CTX_verify_cb verify_cb)
{
ctx->verify_cb = verify_cb;
}
X509_STORE_CTX_verify_cb X509_STORE_CTX_get_verify_cb(X509_STORE_CTX *ctx)
{
return ctx->verify_cb;
}
void X509_STORE_CTX_set_verify(X509_STORE_CTX *ctx,
X509_STORE_CTX_verify_fn verify)
{
ctx->verify = verify;
}
X509_STORE_CTX_verify_fn X509_STORE_CTX_get_verify(X509_STORE_CTX *ctx)
{
return ctx->verify;
}
X509_STORE_CTX_get_issuer_fn X509_STORE_CTX_get_get_issuer(X509_STORE_CTX *ctx)
{
return ctx->get_issuer;
}
X509_STORE_CTX_check_issued_fn X509_STORE_CTX_get_check_issued(X509_STORE_CTX *ctx)
{
return ctx->check_issued;
}
X509_STORE_CTX_check_revocation_fn X509_STORE_CTX_get_check_revocation(X509_STORE_CTX *ctx)
{
return ctx->check_revocation;
}
X509_STORE_CTX_get_crl_fn X509_STORE_CTX_get_get_crl(X509_STORE_CTX *ctx)
{
return ctx->get_crl;
}
X509_STORE_CTX_check_crl_fn X509_STORE_CTX_get_check_crl(X509_STORE_CTX *ctx)
{
return ctx->check_crl;
}
X509_STORE_CTX_cert_crl_fn X509_STORE_CTX_get_cert_crl(X509_STORE_CTX *ctx)
{
return ctx->cert_crl;
}
X509_STORE_CTX_check_policy_fn X509_STORE_CTX_get_check_policy(X509_STORE_CTX *ctx)
{
return ctx->check_policy;
}
X509_STORE_CTX_lookup_certs_fn X509_STORE_CTX_get_lookup_certs(X509_STORE_CTX *ctx)
{
return ctx->lookup_certs;
}
X509_STORE_CTX_lookup_crls_fn X509_STORE_CTX_get_lookup_crls(X509_STORE_CTX *ctx)
{
return ctx->lookup_crls;
}
X509_STORE_CTX_cleanup_fn X509_STORE_CTX_get_cleanup(X509_STORE_CTX *ctx)
{
return ctx->cleanup;
}
X509_POLICY_TREE *X509_STORE_CTX_get0_policy_tree(X509_STORE_CTX *ctx)
{
return ctx->tree;
}
int X509_STORE_CTX_get_explicit_policy(X509_STORE_CTX *ctx)
{
return ctx->explicit_policy;
}
int X509_STORE_CTX_get_num_untrusted(X509_STORE_CTX *ctx)
{
return ctx->num_untrusted;
}
int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx, const char *name)
{
const X509_VERIFY_PARAM *param;
param = X509_VERIFY_PARAM_lookup(name);
if (!param)
return 0;
return X509_VERIFY_PARAM_inherit(ctx->param, param);
}
X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(X509_STORE_CTX *ctx)
{
return ctx->param;
}
void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx, X509_VERIFY_PARAM *param)
{
X509_VERIFY_PARAM_free(ctx->param);
ctx->param = param;
}
void X509_STORE_CTX_set0_dane(X509_STORE_CTX *ctx, SSL_DANE *dane)
{
ctx->dane = dane;
}
static unsigned char *dane_i2d(
X509 *cert,
uint8_t selector,
unsigned int *i2dlen)
{
unsigned char *buf = NULL;
int len;
/*
* Extract ASN.1 DER form of certificate or public key.
*/
switch (selector) {
case DANETLS_SELECTOR_CERT:
len = i2d_X509(cert, &buf);
break;
case DANETLS_SELECTOR_SPKI:
len = i2d_X509_PUBKEY(X509_get_X509_PUBKEY(cert), &buf);
break;
default:
X509err(X509_F_DANE_I2D, X509_R_BAD_SELECTOR);
return NULL;
}
if (len < 0 || buf == NULL) {
X509err(X509_F_DANE_I2D, ERR_R_MALLOC_FAILURE);
return NULL;
}
*i2dlen = (unsigned int)len;
return buf;
}
#define DANETLS_NONE 256 /* impossible uint8_t */
static int dane_match(X509_STORE_CTX *ctx, X509 *cert, int depth)
{
SSL_DANE *dane = ctx->dane;
unsigned usage = DANETLS_NONE;
unsigned selector = DANETLS_NONE;
unsigned ordinal = DANETLS_NONE;
unsigned mtype = DANETLS_NONE;
unsigned char *i2dbuf = NULL;
unsigned int i2dlen = 0;
unsigned char mdbuf[EVP_MAX_MD_SIZE];
unsigned char *cmpbuf = NULL;
unsigned int cmplen = 0;
int i;
int recnum;
int matched = 0;
danetls_record *t = NULL;
uint32_t mask;
mask = (depth == 0) ? DANETLS_EE_MASK : DANETLS_TA_MASK;
/*
* The trust store is not applicable with DANE-TA(2)
*/
if (depth >= ctx->num_untrusted)
mask &= DANETLS_PKIX_MASK;
/*
* If we've previously matched a PKIX-?? record, no need to test any
* further PKIX-?? records, it remains to just build the PKIX chain.
* Had the match been a DANE-?? record, we'd be done already.
*/
if (dane->mdpth >= 0)
mask &= ~DANETLS_PKIX_MASK;
/*-
* https://tools.ietf.org/html/rfc7671#section-5.1
* https://tools.ietf.org/html/rfc7671#section-5.2
* https://tools.ietf.org/html/rfc7671#section-5.3
* https://tools.ietf.org/html/rfc7671#section-5.4
*
* We handle DANE-EE(3) records first as they require no chain building
* and no expiration or hostname checks. We also process digests with
* higher ordinals first and ignore lower priorities except Full(0) which
* is always processed (last). If none match, we then process PKIX-EE(1).
*
* NOTE: This relies on DANE usages sorting before the corresponding PKIX
* usages in SSL_dane_tlsa_add(), and also on descending sorting of digest
* priorities. See twin comment in ssl/ssl_lib.c.
*
* We expect that most TLSA RRsets will have just a single usage, so we
* don't go out of our way to cache multiple selector-specific i2d buffers
* across usages, but if the selector happens to remain the same as switch
* usages, that's OK. Thus, a set of "3 1 1", "3 0 1", "1 1 1", "1 0 1",
* records would result in us generating each of the certificate and public
* key DER forms twice, but more typically we'd just see multiple "3 1 1"
* or multiple "3 0 1" records.
*
* As soon as we find a match at any given depth, we stop, because either
* we've matched a DANE-?? record and the peer is authenticated, or, after
* exhausting all DANE-?? records, we've matched a PKIX-?? record, which is
* sufficient for DANE, and what remains to do is ordinary PKIX validation.
*/
recnum = (dane->umask & mask) ? sk_danetls_record_num(dane->trecs) : 0;
for (i = 0; matched == 0 && i < recnum; ++i) {
t = sk_danetls_record_value(dane->trecs, i);
if ((DANETLS_USAGE_BIT(t->usage) & mask) == 0)
continue;
if (t->usage != usage) {
usage = t->usage;
/* Reset digest agility for each usage/selector pair */
mtype = DANETLS_NONE;
ordinal = dane->dctx->mdord[t->mtype];
}
if (t->selector != selector) {
selector = t->selector;
/* Update per-selector state */
OPENSSL_free(i2dbuf);
i2dbuf = dane_i2d(cert, selector, &i2dlen);
if (i2dbuf == NULL)
return -1;
/* Reset digest agility for each usage/selector pair */
mtype = DANETLS_NONE;
ordinal = dane->dctx->mdord[t->mtype];
} else if (t->mtype != DANETLS_MATCHING_FULL) {
/*-
* Digest agility:
*
* <https://tools.ietf.org/html/rfc7671#section-9>
*
* For a fixed selector, after processing all records with the
* highest mtype ordinal, ignore all mtypes with lower ordinals
* other than "Full".
*/
if (dane->dctx->mdord[t->mtype] < ordinal)
continue;
}
/*
* Each time we hit a (new selector or) mtype, re-compute the relevant
* digest, more complex caching is not worth the code space.
*/
if (t->mtype != mtype) {
const EVP_MD *md = dane->dctx->mdevp[mtype = t->mtype];
cmpbuf = i2dbuf;
cmplen = i2dlen;
if (md != NULL) {
cmpbuf = mdbuf;
if (!EVP_Digest(i2dbuf, i2dlen, cmpbuf, &cmplen, md, 0)) {
matched = -1;
break;
}
}
}
/*
* Squirrel away the certificate and depth if we have a match. Any
* DANE match is dispositive, but with PKIX we still need to build a
* full chain.
*/
if (cmplen == t->dlen &&
memcmp(cmpbuf, t->data, cmplen) == 0) {
if (DANETLS_USAGE_BIT(usage) & DANETLS_DANE_MASK)
matched = 1;
if (matched || dane->mdpth < 0) {
dane->mdpth = depth;
dane->mtlsa = t;
OPENSSL_free(dane->mcert);
dane->mcert = cert;
X509_up_ref(cert);
}
break;
}
}
/* Clear the one-element DER cache */
OPENSSL_free(i2dbuf);
return matched;
}
static int check_dane_issuer(X509_STORE_CTX *ctx, int depth)
{
SSL_DANE *dane = ctx->dane;
int matched = 0;
X509 *cert;
if (!DANETLS_HAS_TA(dane) || depth == 0)
return X509_TRUST_UNTRUSTED;
/*
* Record any DANE trust-anchor matches, for the first depth to test, if
* there's one at that depth. (This'll be false for length 1 chains looking
* for an exact match for the leaf certificate).
*/
cert = sk_X509_value(ctx->chain, depth);
if (cert != NULL && (matched = dane_match(ctx, cert, depth)) < 0)
return X509_TRUST_REJECTED;
if (matched > 0) {
ctx->num_untrusted = depth - 1;
return X509_TRUST_TRUSTED;
}
return X509_TRUST_UNTRUSTED;
}
static int check_dane_pkeys(X509_STORE_CTX *ctx)
{
SSL_DANE *dane = ctx->dane;
danetls_record *t;
int num = ctx->num_untrusted;
X509 *cert = sk_X509_value(ctx->chain, num - 1);
int recnum = sk_danetls_record_num(dane->trecs);
int i;
for (i = 0; i < recnum; ++i) {
t = sk_danetls_record_value(dane->trecs, i);
if (t->usage != DANETLS_USAGE_DANE_TA ||
t->selector != DANETLS_SELECTOR_SPKI ||
t->mtype != DANETLS_MATCHING_FULL ||
X509_verify(cert, t->spki) <= 0)
continue;
/* Clear any PKIX-?? matches that failed to extend to a full chain */
X509_free(dane->mcert);
dane->mcert = NULL;
/* Record match via a bare TA public key */
ctx->bare_ta_signed = 1;
dane->mdpth = num - 1;
dane->mtlsa = t;
/* Prune any excess chain certificates */
num = sk_X509_num(ctx->chain);
for (; num > ctx->num_untrusted; --num)
X509_free(sk_X509_pop(ctx->chain));
return X509_TRUST_TRUSTED;
}
return X509_TRUST_UNTRUSTED;
}
static void dane_reset(SSL_DANE *dane)
{
/*
* Reset state to verify another chain, or clear after failure.
*/
X509_free(dane->mcert);
dane->mcert = NULL;
dane->mtlsa = NULL;
dane->mdpth = -1;
dane->pdpth = -1;
}
static int check_leaf_suiteb(X509_STORE_CTX *ctx, X509 *cert)
{
int err = X509_chain_check_suiteb(NULL, cert, NULL, ctx->param->flags);
if (err == X509_V_OK)
return 1;
return verify_cb_cert(ctx, cert, 0, err);
}
static int dane_verify(X509_STORE_CTX *ctx)
{
X509 *cert = ctx->cert;
SSL_DANE *dane = ctx->dane;
int matched;
int done;
dane_reset(dane);
/*-
* When testing the leaf certificate, if we match a DANE-EE(3) record,
* dane_match() returns 1 and we're done. If however we match a PKIX-EE(1)
* record, the match depth and matching TLSA record are recorded, but the
* return value is 0, because we still need to find a PKIX trust-anchor.
* Therefore, when DANE authentication is enabled (required), we're done
* if:
* + matched < 0, internal error.
* + matched == 1, we matched a DANE-EE(3) record
* + matched == 0, mdepth < 0 (no PKIX-EE match) and there are no
* DANE-TA(2) or PKIX-TA(0) to test.
*/
matched = dane_match(ctx, ctx->cert, 0);
done = matched != 0 || (!DANETLS_HAS_TA(dane) && dane->mdpth < 0);
if (done)
X509_get_pubkey_parameters(NULL, ctx->chain);
if (matched > 0) {
/* Callback invoked as needed */
if (!check_leaf_suiteb(ctx, cert))
return 0;
/* Callback invoked as needed */
if ((dane->flags & DANE_FLAG_NO_DANE_EE_NAMECHECKS) == 0 &&
!check_id(ctx))
return 0;
/* Bypass internal_verify(), issue depth 0 success callback */
ctx->error_depth = 0;
ctx->current_cert = cert;
return ctx->verify_cb(1, ctx);
}
if (matched < 0) {
ctx->error_depth = 0;
ctx->current_cert = cert;
ctx->error = X509_V_ERR_OUT_OF_MEM;
return -1;
}
if (done) {
/* Fail early, TA-based success is not possible */
if (!check_leaf_suiteb(ctx, cert))
return 0;
return verify_cb_cert(ctx, cert, 0, X509_V_ERR_DANE_NO_MATCH);
}
/*
* Chain verification for usages 0/1/2. TLSA record matching of depth > 0
* certificates happens in-line with building the rest of the chain.
*/
return verify_chain(ctx);
}
/* Get issuer, without duplicate suppression */
static int get_issuer(X509 **issuer, X509_STORE_CTX *ctx, X509 *cert)
{
STACK_OF(X509) *saved_chain = ctx->chain;
int ok;
ctx->chain = NULL;
ok = ctx->get_issuer(issuer, ctx, cert);
ctx->chain = saved_chain;
return ok;
}
static int build_chain(X509_STORE_CTX *ctx)
{
SSL_DANE *dane = ctx->dane;
int num = sk_X509_num(ctx->chain);
X509 *cert = sk_X509_value(ctx->chain, num - 1);
int ss = cert_self_signed(cert);
STACK_OF(X509) *sktmp = NULL;
unsigned int search;
int may_trusted = 0;
int may_alternate = 0;
int trust = X509_TRUST_UNTRUSTED;
int alt_untrusted = 0;
int depth;
int ok = 0;
int i;
/* Our chain starts with a single untrusted element. */
if (!ossl_assert(num == 1 && ctx->num_untrusted == num)) {
X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
ctx->error = X509_V_ERR_UNSPECIFIED;
return 0;
}
#define S_DOUNTRUSTED (1 << 0) /* Search untrusted chain */
#define S_DOTRUSTED (1 << 1) /* Search trusted store */
#define S_DOALTERNATE (1 << 2) /* Retry with pruned alternate chain */
/*
* Set up search policy, untrusted if possible, trusted-first if enabled.
* If we're doing DANE and not doing PKIX-TA/PKIX-EE, we never look in the
* trust_store, otherwise we might look there first. If not trusted-first,
* and alternate chains are not disabled, try building an alternate chain
* if no luck with untrusted first.
*/
search = (ctx->untrusted != NULL) ? S_DOUNTRUSTED : 0;
if (DANETLS_HAS_PKIX(dane) || !DANETLS_HAS_DANE(dane)) {
if (search == 0 || ctx->param->flags & X509_V_FLAG_TRUSTED_FIRST)
search |= S_DOTRUSTED;
else if (!(ctx->param->flags & X509_V_FLAG_NO_ALT_CHAINS))
may_alternate = 1;
may_trusted = 1;
}
/*
* Shallow-copy the stack of untrusted certificates (with TLS, this is
* typically the content of the peer's certificate message) so can make
* multiple passes over it, while free to remove elements as we go.
*/
if (ctx->untrusted && (sktmp = sk_X509_dup(ctx->untrusted)) == NULL) {
X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
/*
* If we got any "DANE-TA(2) Cert(0) Full(0)" trust-anchors from DNS, add
* them to our working copy of the untrusted certificate stack. Since the
* caller of X509_STORE_CTX_init() may have provided only a leaf cert with
* no corresponding stack of untrusted certificates, we may need to create
* an empty stack first. [ At present only the ssl library provides DANE
* support, and ssl_verify_cert_chain() always provides a non-null stack
* containing at least the leaf certificate, but we must be prepared for
* this to change. ]
*/
if (DANETLS_ENABLED(dane) && dane->certs != NULL) {
if (sktmp == NULL && (sktmp = sk_X509_new_null()) == NULL) {
X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
for (i = 0; i < sk_X509_num(dane->certs); ++i) {
if (!sk_X509_push(sktmp, sk_X509_value(dane->certs, i))) {
sk_X509_free(sktmp);
X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
}
}
/*
* Still absurdly large, but arithmetically safe, a lower hard upper bound
* might be reasonable.
*/
if (ctx->param->depth > INT_MAX/2)
ctx->param->depth = INT_MAX/2;
/*
* Try to Extend the chain until we reach an ultimately trusted issuer.
* Build chains up to one longer the limit, later fail if we hit the limit,
* with an X509_V_ERR_CERT_CHAIN_TOO_LONG error code.
*/
depth = ctx->param->depth + 1;
while (search != 0) {
X509 *x;
X509 *xtmp = NULL;
/*
* Look in the trust store if enabled for first lookup, or we've run
* out of untrusted issuers and search here is not disabled. When we
* reach the depth limit, we stop extending the chain, if by that point
* we've not found a trust-anchor, any trusted chain would be too long.
*
* The error reported to the application verify callback is at the
* maximal valid depth with the current certificate equal to the last
* not ultimately-trusted issuer. For example, with verify_depth = 0,
* the callback will report errors at depth=1 when the immediate issuer
* of the leaf certificate is not a trust anchor. No attempt will be
* made to locate an issuer for that certificate, since such a chain
* would be a-priori too long.
*/
if ((search & S_DOTRUSTED) != 0) {
i = num = sk_X509_num(ctx->chain);
if ((search & S_DOALTERNATE) != 0) {
/*
* As high up the chain as we can, look for an alternative
* trusted issuer of an untrusted certificate that currently
* has an untrusted issuer. We use the alt_untrusted variable
* to track how far up the chain we find the first match. It
* is only if and when we find a match, that we prune the chain
* and reset ctx->num_untrusted to the reduced count of
* untrusted certificates. While we're searching for such a
* match (which may never be found), it is neither safe nor
* wise to preemptively modify either the chain or
* ctx->num_untrusted.
*
* Note, like ctx->num_untrusted, alt_untrusted is a count of
* untrusted certificates, not a "depth".
*/
i = alt_untrusted;
}
x = sk_X509_value(ctx->chain, i-1);
ok = (depth < num) ? 0 : get_issuer(&xtmp, ctx, x);
if (ok < 0) {
trust = X509_TRUST_REJECTED;
ctx->error = X509_V_ERR_STORE_LOOKUP;
search = 0;
continue;
}
if (ok > 0) {
/*
* Alternative trusted issuer for a mid-chain untrusted cert?
* Pop the untrusted cert's successors and retry. We might now
* be able to complete a valid chain via the trust store. Note
* that despite the current trust-store match we might still
* fail complete the chain to a suitable trust-anchor, in which
* case we may prune some more untrusted certificates and try
* again. Thus the S_DOALTERNATE bit may yet be turned on
* again with an even shorter untrusted chain!
*
* If in the process we threw away our matching PKIX-TA trust
* anchor, reset DANE trust. We might find a suitable trusted
* certificate among the ones from the trust store.
*/
if ((search & S_DOALTERNATE) != 0) {
if (!ossl_assert(num > i && i > 0 && ss == 0)) {
X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
X509_free(xtmp);
trust = X509_TRUST_REJECTED;
ctx->error = X509_V_ERR_UNSPECIFIED;
search = 0;
continue;
}
search &= ~S_DOALTERNATE;
for (; num > i; --num)
X509_free(sk_X509_pop(ctx->chain));
ctx->num_untrusted = num;
if (DANETLS_ENABLED(dane) &&
dane->mdpth >= ctx->num_untrusted) {
dane->mdpth = -1;
X509_free(dane->mcert);
dane->mcert = NULL;
}
if (DANETLS_ENABLED(dane) &&
dane->pdpth >= ctx->num_untrusted)
dane->pdpth = -1;
}
/*
* Self-signed untrusted certificates get replaced by their
* trusted matching issuer. Otherwise, grow the chain.
*/
if (ss == 0) {
if (!sk_X509_push(ctx->chain, x = xtmp)) {
X509_free(xtmp);
X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
trust = X509_TRUST_REJECTED;
ctx->error = X509_V_ERR_OUT_OF_MEM;
search = 0;
continue;
}
ss = cert_self_signed(x);
} else if (num == ctx->num_untrusted) {
/*
* We have a self-signed certificate that has the same
* subject name (and perhaps keyid and/or serial number) as
* a trust-anchor. We must have an exact match to avoid
* possible impersonation via key substitution etc.
*/
if (X509_cmp(x, xtmp) != 0) {
/* Self-signed untrusted mimic. */
X509_free(xtmp);
ok = 0;
} else {
X509_free(x);
ctx->num_untrusted = --num;
(void) sk_X509_set(ctx->chain, num, x = xtmp);
}
}
/*
* We've added a new trusted certificate to the chain, recheck
* trust. If not done, and not self-signed look deeper.
* Whether or not we're doing "trusted first", we no longer
* look for untrusted certificates from the peer's chain.
*
* At this point ctx->num_trusted and num must reflect the
* correct number of untrusted certificates, since the DANE
* logic in check_trust() depends on distinguishing CAs from
* "the wire" from CAs from the trust store. In particular, the
* certificate at depth "num" should be the new trusted
* certificate with ctx->num_untrusted <= num.
*/
if (ok) {
if (!ossl_assert(ctx->num_untrusted <= num)) {
X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
trust = X509_TRUST_REJECTED;
ctx->error = X509_V_ERR_UNSPECIFIED;
search = 0;
continue;
}
search &= ~S_DOUNTRUSTED;
switch (trust = check_trust(ctx, num)) {
case X509_TRUST_TRUSTED:
case X509_TRUST_REJECTED:
search = 0;
continue;
}
if (ss == 0)
continue;
}
}
/*
* No dispositive decision, and either self-signed or no match, if
* we were doing untrusted-first, and alt-chains are not disabled,
* do that, by repeatedly losing one untrusted element at a time,
* and trying to extend the shorted chain.
*/
if ((search & S_DOUNTRUSTED) == 0) {
/* Continue search for a trusted issuer of a shorter chain? */
if ((search & S_DOALTERNATE) != 0 && --alt_untrusted > 0)
continue;
/* Still no luck and no fallbacks left? */
if (!may_alternate || (search & S_DOALTERNATE) != 0 ||
ctx->num_untrusted < 2)
break;
/* Search for a trusted issuer of a shorter chain */
search |= S_DOALTERNATE;
alt_untrusted = ctx->num_untrusted - 1;
ss = 0;
}
}
/*
* Extend chain with peer-provided certificates
*/
if ((search & S_DOUNTRUSTED) != 0) {
num = sk_X509_num(ctx->chain);
if (!ossl_assert(num == ctx->num_untrusted)) {
X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
trust = X509_TRUST_REJECTED;
ctx->error = X509_V_ERR_UNSPECIFIED;
search = 0;
continue;
}
x = sk_X509_value(ctx->chain, num-1);
/*
* Once we run out of untrusted issuers, we stop looking for more
* and start looking only in the trust store if enabled.
*/
xtmp = (ss || depth < num) ? NULL : find_issuer(ctx, sktmp, x);
if (xtmp == NULL) {
search &= ~S_DOUNTRUSTED;
if (may_trusted)
search |= S_DOTRUSTED;
continue;
}
/* Drop this issuer from future consideration */
(void) sk_X509_delete_ptr(sktmp, xtmp);
if (!sk_X509_push(ctx->chain, xtmp)) {
X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
trust = X509_TRUST_REJECTED;
ctx->error = X509_V_ERR_OUT_OF_MEM;
search = 0;
continue;
}
X509_up_ref(x = xtmp);
++ctx->num_untrusted;
ss = cert_self_signed(xtmp);
/*
* Check for DANE-TA trust of the topmost untrusted certificate.
*/
switch (trust = check_dane_issuer(ctx, ctx->num_untrusted - 1)) {
case X509_TRUST_TRUSTED:
case X509_TRUST_REJECTED:
search = 0;
continue;
}
}
}
sk_X509_free(sktmp);
/*
* Last chance to make a trusted chain, either bare DANE-TA public-key
* signers, or else direct leaf PKIX trust.
*/
num = sk_X509_num(ctx->chain);
if (num <= depth) {
if (trust == X509_TRUST_UNTRUSTED && DANETLS_HAS_DANE_TA(dane))
trust = check_dane_pkeys(ctx);
if (trust == X509_TRUST_UNTRUSTED && num == ctx->num_untrusted)
trust = check_trust(ctx, num);
}
switch (trust) {
case X509_TRUST_TRUSTED:
return 1;
case X509_TRUST_REJECTED:
/* Callback already issued */
return 0;
case X509_TRUST_UNTRUSTED:
default:
num = sk_X509_num(ctx->chain);
if (num > depth)
return verify_cb_cert(ctx, NULL, num-1,
X509_V_ERR_CERT_CHAIN_TOO_LONG);
if (DANETLS_ENABLED(dane) &&
(!DANETLS_HAS_PKIX(dane) || dane->pdpth >= 0))
return verify_cb_cert(ctx, NULL, num-1, X509_V_ERR_DANE_NO_MATCH);
if (ss && sk_X509_num(ctx->chain) == 1)
return verify_cb_cert(ctx, NULL, num-1,
X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT);
if (ss)
return verify_cb_cert(ctx, NULL, num-1,
X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN);
if (ctx->num_untrusted < num)
return verify_cb_cert(ctx, NULL, num-1,
X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT);
return verify_cb_cert(ctx, NULL, num-1,
X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY);
}
}
static const int minbits_table[] = { 80, 112, 128, 192, 256 };
static const int NUM_AUTH_LEVELS = OSSL_NELEM(minbits_table);
/*
* Check whether the public key of ``cert`` meets the security level of
* ``ctx``.
*
* Returns 1 on success, 0 otherwise.
*/
static int check_key_level(X509_STORE_CTX *ctx, X509 *cert)
{
EVP_PKEY *pkey = X509_get0_pubkey(cert);
int level = ctx->param->auth_level;
/* Unsupported or malformed keys are not secure */
if (pkey == NULL)
return 0;
if (level <= 0)
return 1;
if (level > NUM_AUTH_LEVELS)
level = NUM_AUTH_LEVELS;
return EVP_PKEY_security_bits(pkey) >= minbits_table[level - 1];
}
/*
* Check whether the signature digest algorithm of ``cert`` meets the security
* level of ``ctx``. Should not be checked for trust anchors (whether
* self-signed or otherwise).
*
* Returns 1 on success, 0 otherwise.
*/
static int check_sig_level(X509_STORE_CTX *ctx, X509 *cert)
{
int secbits = -1;
int level = ctx->param->auth_level;
if (level <= 0)
return 1;
if (level > NUM_AUTH_LEVELS)
level = NUM_AUTH_LEVELS;
if (!X509_get_signature_info(cert, NULL, NULL, &secbits, NULL))
return 0;
return secbits >= minbits_table[level - 1];
}
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