Support for AKID in CRLs and partial support for IDP. Overhaul of CRL

handling to support this.
This commit is contained in:
Dr. Stephen Henson 2006-09-14 17:25:02 +00:00
parent 83357f047d
commit bc7535bc7f
6 changed files with 218 additions and 41 deletions

12
CHANGES
View file

@ -4,6 +4,18 @@
Changes between 0.9.8d and 0.9.9 [xx XXX xxxx]
*) Partial support for Issuing Distribution Point CRL extension. CRLs
partitioned by DP are handled but no indirect CRL or reason partitioning
(yet). Complete overhaul of CRL handling: now the most suitable CRL is
selected via a scoring technique which handles IDP and AKID in CRLs.
[Steve Henson]
*) New X509_STORE_CTX callbacks lookup_crls() and lookup_certs() which
will ultimately be used for all verify operations: this will remove the
X509_STORE dependency on certificate verification and allow alternative
lookup methods. X509_STORE based implementations of these two callbacks.
[Steve Henson]
*) Allow multiple CRLs to exist in an X509_STORE with matching issuer names.
Modify get_crl() to find a valid (unexpired) CRL if possible.
[Steve Henson]

View file

@ -162,6 +162,10 @@ const char *X509_verify_cert_error_string(long n)
return("invalid or inconsistent certificate policy extension");
case X509_V_ERR_NO_EXPLICIT_POLICY:
return("no explicit policy");
case X509_V_ERR_DIFFERENT_CRL_SCOPE:
return("Different CRL scope");
case X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE:
return("Unsupported extension feature");
default:
BIO_snprintf(buf,sizeof buf,"error number %ld",n);
return(buf);

View file

@ -78,6 +78,8 @@ static int check_trust(X509_STORE_CTX *ctx);
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 crl_akid_check(X509_STORE_CTX *ctx, AUTHORITY_KEYID *akid);
static int idp_check_scope(X509 *x, X509_CRL *crl);
static int internal_verify(X509_STORE_CTX *ctx);
const char *X509_version="X.509" OPENSSL_VERSION_PTEXT;
@ -649,30 +651,81 @@ static int check_crl_time(X509_STORE_CTX *ctx, X509_CRL *crl, int notify)
return 1;
}
/* Lookup CRLs from the supplied list. Look for matching isser name
* and validity. If we can't find a valid CRL return the last one
* with matching name. This gives more meaningful error codes. Otherwise
* we'd get a CRL not found error if a CRL existed with matching name but
* was invalid.
/* Based on a set of possible CRLs decide which one is best suited
* to handle the current certificate. This is determined by a number
* of criteria. If any of the "must" criteria is not satisfied then
* the candidate CRL is rejected. If all "must" and all "should" are
* satisfied the CRL is accepted. If no CRL satisfies all criteria then
* a "best CRL" is used to provide some meaningful error information.
*
* CRL issuer name must match "nm" if not NULL.
* If IDP is present:
* a. it must be consistent.
* b. onlyuser, onlyCA, onlyAA should match certificate being checked.
* c. indirectCRL must be FALSE.
* d. onlysomereason must be absent.
* e. if name present a DP in certificate CRLDP must match.
* If AKID present it should match certificate AKID.
* Check time should fall between lastUpdate and nextUpdate.
*/
/* IDP name field matches CRLDP or IDP name not present */
#define CRL_SCORE_SCOPE 4
/* AKID present and matches cert, or AKID not present */
#define CRL_SCORE_AKID 2
/* times OK */
#define CRL_SCORE_TIME 1
#define CRL_SCORE_ALL 7
/* IDP flags which cause a CRL to be rejected */
#define IDP_REJECT (IDP_INVALID|IDP_INDIRECT|IDP_REASONS)
static int get_crl_sk(X509_STORE_CTX *ctx, X509_CRL **pcrl,
X509_NAME *nm, STACK_OF(X509_CRL) *crls)
{
int i;
int i, crl_score, best_score = -1;
X509_CRL *crl, *best_crl = NULL;
for (i = 0; i < sk_X509_CRL_num(crls); i++)
{
crl_score = 0;
crl = sk_X509_CRL_value(crls, i);
if (nm && X509_NAME_cmp(nm, X509_CRL_get_issuer(crl)))
continue;
if (check_crl_time(ctx, crl, 0))
crl_score |= CRL_SCORE_TIME;
if (crl->idp_flags & IDP_PRESENT)
{
if (crl->idp_flags & IDP_REJECT)
continue;
if (idp_check_scope(ctx->current_cert, crl))
crl_score |= CRL_SCORE_SCOPE;
}
else
crl_score |= CRL_SCORE_SCOPE;
if (crl->akid)
{
if (crl_akid_check(ctx, crl->akid))
crl_score |= CRL_SCORE_AKID;
}
else
crl_score |= CRL_SCORE_AKID;
if (crl_score == CRL_SCORE_ALL)
{
*pcrl = crl;
CRYPTO_add(&crl->references, 1, CRYPTO_LOCK_X509_CRL);
return 1;
}
if (crl_score > best_score)
{
best_crl = crl;
best_score = crl_score;
}
}
if (best_crl)
{
@ -683,9 +736,71 @@ static int get_crl_sk(X509_STORE_CTX *ctx, X509_CRL **pcrl,
return 0;
}
/* Retrieve CRL corresponding to certificate: currently just a
* subject lookup: maybe use AKID later...
static int crl_akid_check(X509_STORE_CTX *ctx, AUTHORITY_KEYID *akid)
{
int cidx = ctx->error_depth;
if (cidx != sk_X509_num(ctx->chain) - 1)
cidx++;
if (X509_check_akid(sk_X509_value(ctx->chain, cidx), akid) == X509_V_OK)
return 1;
return 0;
}
/* Check IDP name matches at least one CRLDP name */
static int idp_check_scope(X509 *x, X509_CRL *crl)
{
int i, j, k;
GENERAL_NAMES *inames, *dnames;
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;
}
if (!crl->idp->distpoint)
return 1;
if (crl->idp->distpoint->type != 0)
return 1;
if (!x->crldp)
return 0;
inames = crl->idp->distpoint->name.fullname;
for (i = 0; i < sk_GENERAL_NAME_num(inames); i++)
{
GENERAL_NAME *igen = sk_GENERAL_NAME_value(inames, i);
for (j = 0; j < sk_DIST_POINT_num(x->crldp); j++)
{
DIST_POINT *dp = sk_DIST_POINT_value(x->crldp, j);
/* We don't handle these at present */
if (dp->reasons || dp->CRLissuer)
continue;
if (!dp->distpoint || (dp->distpoint->type != 0))
continue;
dnames = dp->distpoint->name.fullname;
for (k = 0; k < sk_GENERAL_NAME_num(dnames); k++)
{
GENERAL_NAME *cgen =
sk_GENERAL_NAME_value(dnames, k);
if (!GENERAL_NAME_cmp(igen, cgen))
return 1;
}
}
}
return 0;
}
/* Retrieve CRL corresponding to current certificate. Currently only
* one CRL is retrieved. Multiple CRLs may be needed if we handle
* CRLs partitioned on reason code later.
*/
static int get_crl(X509_STORE_CTX *ctx, X509_CRL **pcrl, X509 *x)
{
int ok;
@ -765,6 +880,28 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl)
if(!ok) goto err;
}
if (crl->idp_flags & IDP_PRESENT)
{
if (crl->idp_flags & IDP_INVALID)
{
ctx->error = X509_V_ERR_INVALID_EXTENSION;
ok = ctx->verify_cb(0, ctx);
if(!ok) goto err;
}
if (crl->idp_flags & (IDP_REASONS|IDP_INDIRECT))
{
ctx->error = X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE;
ok = ctx->verify_cb(0, ctx);
if(!ok) goto err;
}
if (!idp_check_scope(ctx->current_cert, crl))
{
ctx->error = X509_V_ERR_DIFFERENT_CRL_SCOPE;
ok = ctx->verify_cb(0, ctx);
if(!ok) goto err;
}
}
/* Attempt to get issuer certificate public key */
ikey = X509_get_pubkey(issuer);
@ -843,6 +980,10 @@ static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x)
ext = sk_X509_EXTENSION_value(exts, idx);
if (ext->critical > 0)
{
/* We handle IDP now so permit it */
if (OBJ_obj2nid(ext->object) ==
NID_issuing_distribution_point)
continue;
ctx->error =
X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION;
ok = ctx->verify_cb(0, ctx);

View file

@ -334,6 +334,8 @@ void X509_STORE_CTX_set_depth(X509_STORE_CTX *ctx, int depth);
#define X509_V_ERR_INVALID_EXTENSION 41
#define X509_V_ERR_INVALID_POLICY_EXTENSION 42
#define X509_V_ERR_NO_EXPLICIT_POLICY 43
#define X509_V_ERR_DIFFERENT_CRL_SCOPE 44
#define X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE 45
/* The application is not happy */

View file

@ -644,39 +644,14 @@ int X509_check_issued(X509 *issuer, X509 *subject)
return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
x509v3_cache_extensions(issuer);
x509v3_cache_extensions(subject);
if(subject->akid) {
/* Check key ids (if present) */
if(subject->akid->keyid && issuer->skid &&
ASN1_OCTET_STRING_cmp(subject->akid->keyid, issuer->skid) )
return X509_V_ERR_AKID_SKID_MISMATCH;
/* Check serial number */
if(subject->akid->serial &&
ASN1_INTEGER_cmp(X509_get_serialNumber(issuer),
subject->akid->serial))
return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
/* Check issuer name */
if(subject->akid->issuer) {
/* Ugh, for some peculiar reason AKID includes
* SEQUENCE OF GeneralName. So look for a DirName.
* There may be more than one but we only take any
* notice of the first.
*/
GENERAL_NAMES *gens;
GENERAL_NAME *gen;
X509_NAME *nm = NULL;
int i;
gens = subject->akid->issuer;
for(i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
gen = sk_GENERAL_NAME_value(gens, i);
if(gen->type == GEN_DIRNAME) {
nm = gen->d.dirn;
break;
}
}
if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
}
if(subject->akid)
{
int ret = X509_check_akid(issuer, subject->akid);
if (ret != X509_V_OK)
return ret;
}
if(subject->ex_flags & EXFLAG_PROXY)
{
if(ku_reject(issuer, KU_DIGITAL_SIGNATURE))
@ -687,3 +662,45 @@ int X509_check_issued(X509 *issuer, X509 *subject)
return X509_V_OK;
}
int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
{
if(!akid)
return X509_V_OK;
/* Check key ids (if present) */
if(akid->keyid && issuer->skid &&
ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) )
return X509_V_ERR_AKID_SKID_MISMATCH;
/* Check serial number */
if(akid->serial &&
ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
/* Check issuer name */
if(akid->issuer)
{
/* Ugh, for some peculiar reason AKID includes
* SEQUENCE OF GeneralName. So look for a DirName.
* There may be more than one but we only take any
* notice of the first.
*/
GENERAL_NAMES *gens;
GENERAL_NAME *gen;
X509_NAME *nm = NULL;
int i;
gens = akid->issuer;
for(i = 0; i < sk_GENERAL_NAME_num(gens); i++)
{
gen = sk_GENERAL_NAME_value(gens, i);
if(gen->type == GEN_DIRNAME)
{
nm = gen->d.dirn;
break;
}
}
if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
}
return X509_V_OK;
}

View file

@ -632,6 +632,7 @@ int X509_check_purpose(X509 *x, int id, int ca);
int X509_supported_extension(X509_EXTENSION *ex);
int X509_PURPOSE_set(int *p, int purpose);
int X509_check_issued(X509 *issuer, X509 *subject);
int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid);
int X509_PURPOSE_get_count(void);
X509_PURPOSE * X509_PURPOSE_get0(int idx);
int X509_PURPOSE_get_by_sname(char *sname);