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openssl/crypto/x509/x509_vfy.c

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v1.1.1t
2023-05-09 22:08:48 +00:00
/*
* Copyright 1995-2022 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 "crypto/ctype.h"
#include "internal/cryptlib.h"
#include <openssl/crypto.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 "crypto/x509.h"
#include "x509_local.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 check_curve(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 if given cert is considered self-signed, 0 if not or on error.
* This does not verify self-signedness but relies on x509v3_cache_extensions()
* matching issuer and subject names (i.e., the cert being self-issued) and any
* present authority key identifier matching the subject key identifier, etc.
*/
static int cert_self_signed(X509 *x)
{
if (X509_check_purpose(x, -1, 0) != 1)
return 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;
xtmp = NULL;
}
if (xtmp != NULL && !X509_up_ref(xtmp))
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_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;
if ((ok = check_name_constraints(ctx)) == 0)
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;
}
if (!X509_up_ref(ctx->cert)) {
X509err(X509_F_X509_VERIFY_CERT, ERR_R_INTERNAL_ERROR);
ctx->error = X509_V_ERR_UNSPECIFIED;
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)) {
X509_free(ctx->cert);
X509err(X509_F_X509_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return -1;
}
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;
}
static int sk_X509_contains(STACK_OF(X509) *sk, X509 *cert)
{
int i, n = sk_X509_num(sk);
for (i = 0; i < n; i++)
if (X509_cmp(sk_X509_value(sk, i), cert) == 0)
return 1;
return 0;
}
/*
* Find in given STACK_OF(X509) sk an issuer cert of given cert x.
* The issuer must not yet be in ctx->chain, where the exceptional case
* that x is self-issued and ctx->chain has just one element is allowed.
* Prefer the first one that is not expired, else take the last expired one.
*/
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)
&& (((x->ex_flags & EXFLAG_SI) != 0 && sk_X509_num(ctx->chain) == 1)
|| !sk_X509_contains(ctx->chain, issuer))) {
rv = issuer;
if (x509_check_cert_time(ctx, rv, -1))
break;
}
}
return rv;
}
/* Check that the given certificate 'x' is issued by the certificate 'issuer' */
static int check_issued(X509_STORE_CTX *ctx, X509 *x, X509 *issuer)
{
return x509_likely_issued(issuer, x) == 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 == NULL || !X509_up_ref(*issuer))
goto err;
return 1;
err:
*issuer = NULL;
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 (!X509_up_ref(x)) {
sk_X509_pop_free(sk, X509_free);
X509err(X509_F_LOOKUP_CERTS_SK, ERR_R_INTERNAL_ERROR);
ctx->error = X509_V_ERR_UNSPECIFIED;
return NULL;
}
if (sk == NULL)
sk = sk_X509_new_null();
if (sk == NULL || !sk_X509_push(sk, x)) {
X509_free(x);
sk_X509_pop_free(sk, X509_free);
X509err(X509_F_LOOKUP_CERTS_SK, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return NULL;
}
}
}
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
&& (ctx->param->flags & X509_V_FLAG_X509_STRICT) && num > 1) {
/* Check for presence of explicit elliptic curve parameters */
ret = check_curve(x);
if (ret < 0) {
ctx->error = X509_V_ERR_UNSPECIFIED;
ret = 0;
} else if (ret == 0) {
ctx->error = X509_V_ERR_EC_KEY_EXPLICIT_PARAMS;
}
}
if (ret > 0
&& (x->ex_flags & EXFLAG_CA) == 0
&& x->ex_pathlen != -1
&& (ctx->param->flags & X509_V_FLAG_X509_STRICT)) {
ctx->error = X509_V_ERR_INVALID_EXTENSION;
ret = 0;
}
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 ((i > 1) && (x->ex_pathlen != -1)
&& (plen > (x->ex_pathlen + proxy_path_length))) {
if (!verify_cb_cert(ctx, x, i, X509_V_ERR_PATH_LENGTH_EXCEEDED))
return 0;
}
/* Increment path length if not a self issued intermediate CA */
if (i > 0 && (x->ex_flags & EXFLAG_SI) == 0)
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 has_san_id(X509 *x, int gtype)
{
int i;
int ret = 0;
GENERAL_NAMES *gs = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
if (gs == NULL)
return 0;
for (i = 0; i < sk_GENERAL_NAME_num(gs); i++) {
GENERAL_NAME *g = sk_GENERAL_NAME_value(gs, i);
if (g->type == gtype) {
ret = 1;
break;
}
}
GENERAL_NAMES_free(gs);
return ret;
}
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
&& (ctx->param->hostflags
& X509_CHECK_FLAG_NEVER_CHECK_SUBJECT) == 0
&& ((ctx->param->hostflags
& X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT) != 0
|| !has_san_id(x, GEN_DNS)))
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 (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;
if (notify)
ctx->current_crl = crl;
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;
}
/* verify the issuer signatures and cert times of ctx->chain */
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_time;
}
if (ctx->check_issued(ctx, xi, xi))
xs = xi; /* the typical case: last cert in the chain is self-issued */
else {
if (ctx->param->flags & X509_V_FLAG_PARTIAL_CHAIN) {
xs = xi;
goto check_cert_time;
}
if (n <= 0) {
if (!verify_cb_cert(ctx, xi, 0,
X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE))
return 0;
xs = xi;
goto check_cert_time;
}
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) {
/*
* For each iteration of this loop:
* n is the subject depth
* xs is the subject cert, for which the signature is to be checked
* xi is the supposed issuer cert containing the public key to use
* Initially xs == xi if the last cert in the chain is self-issued.
*
* Skip signature check for self-signed certificates unless explicitly
* asked for because it does not add any security and just wastes time.
*/
if (xs != xi || ((ctx->param->flags & X509_V_FLAG_CHECK_SS_SIGNATURE)
&& (xi->ex_flags & EXFLAG_SS) != 0)) {
EVP_PKEY *pkey;
/*
* If the issuer's public key is not available or its key usage
* does not support issuing the subject cert, report the issuer
* cert and its depth (rather than n, the depth of the subject).
*/
int issuer_depth = n + (xs == xi ? 0 : 1);
/*
* According to https://tools.ietf.org/html/rfc5280#section-6.1.4
* step (n) we must check any given key usage extension in a CA cert
* when preparing the verification of a certificate issued by it.
* According to https://tools.ietf.org/html/rfc5280#section-4.2.1.3
* we must not verify a certifiate signature if the key usage of the
* CA certificate that issued the certificate prohibits signing.
* In case the 'issuing' certificate is the last in the chain and is
* not a CA certificate but a 'self-issued' end-entity cert (i.e.,
* xs == xi && !(xi->ex_flags & EXFLAG_CA)) RFC 5280 does not apply
* (see https://tools.ietf.org/html/rfc6818#section-2) and thus
* we are free to ignore any key usage restrictions on such certs.
*/
int ret = xs == xi && (xi->ex_flags & EXFLAG_CA) == 0
? X509_V_OK : x509_signing_allowed(xi, xs);
if (ret != X509_V_OK && !verify_cb_cert(ctx, xi, issuer_depth, ret))
return 0;
if ((pkey = X509_get0_pubkey(xi)) == NULL) {
ret = X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY;
if (!verify_cb_cert(ctx, xi, issuer_depth, ret))
return 0;
} else if (X509_verify(xs, pkey) <= 0) {
ret = X509_V_ERR_CERT_SIGNATURE_FAILURE;
if (!verify_cb_cert(ctx, xs, n, ret))
return 0;
}
}
check_cert_time: /* in addition to RFC 5280, do also for trusted (root) 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;
#ifdef CHARSET_EBCDIC
const char upper_z = 0x5A;
#else
const char upper_z = 'Z';
#endif
/*
* 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 (!ascii_isdigit(ctm->data[i]))
return 0;
}
if (ctm->data[ctm->length - 1] != upper_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 purpose is set but we don't have a default then set the default to
* the current purpose
*/
else if (def_purpose == 0)
def_purpose = 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);
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 augment_stack(STACK_OF(X509) *src, STACK_OF(X509) **dstPtr)
{
if (src) {
STACK_OF(X509) *dst;
int i;
if (*dstPtr == NULL)
return ((*dstPtr = sk_X509_dup(src)) != NULL);
for (dst = *dstPtr, i = 0; i < sk_X509_num(src); ++i) {
if (!sk_X509_push(dst, sk_X509_value(src, i))) {
sk_X509_free(dst);
*dstPtr = NULL;
return 0;
}
}
}
return 1;
}
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;
}
/*
* If we got any "Cert(0) Full(0)" issuer certificates from DNS, *prepend*
* 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) && !augment_stack(dane->certs, &sktmp)) {
X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
return 0;
}
/*
* 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 (!augment_stack(ctx->untrusted, &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 (!X509_up_ref(xtmp)) {
X509err(X509_F_BUILD_CHAIN, ERR_R_INTERNAL_ERROR);
trust = X509_TRUST_REJECTED;
ctx->error = X509_V_ERR_UNSPECIFIED;
search = 0;
continue;
}
if (!sk_X509_push(ctx->chain, 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;
}
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;
/*
* At security level zero, return without checking for a supported public
* key type. Some engines support key types not understood outside the
* engine, and we only need to understand the key when enforcing a security
* floor.
*/
if (level <= 0)
return 1;
/* Unsupported or malformed keys are not secure */
if (pkey == NULL)
return 0;
if (level > NUM_AUTH_LEVELS)
level = NUM_AUTH_LEVELS;
return EVP_PKEY_security_bits(pkey) >= minbits_table[level - 1];
}
/*
* Check whether the public key of ``cert`` does not use explicit params
* for an elliptic curve.
*
* Returns 1 on success, 0 if check fails, -1 for other errors.
*/
static int check_curve(X509 *cert)
{
#ifndef OPENSSL_NO_EC
EVP_PKEY *pkey = X509_get0_pubkey(cert);
/* Unsupported or malformed key */
if (pkey == NULL)
return -1;
if (EVP_PKEY_id(pkey) == EVP_PKEY_EC) {
int ret;
ret = EC_KEY_decoded_from_explicit_params(EVP_PKEY_get0_EC_KEY(pkey));
return ret < 0 ? ret : !ret;
}
#endif
return 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];
}