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fix: verification of self issued certificates

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Resolves: #657984
This commit is contained in:
Jan Vcelak 2011-01-06 20:46:58 +01:00
parent 9320cfab96
commit 5ae2484fb8
2 changed files with 326 additions and 1 deletions
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324
openldap-verify-self-issued-certs.patch Normal file
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@ -0,0 +1,324 @@
openldap does not trust certs with Basic Constraint ext. with CA == FALSE
Resolves: #657984
Upstream: ITS #6742
Author: Rich Megginson <rmeggins@redhat.com>
diff -uNPrp openldap-2.4.23/libraries/libldap/tls_m.c openldap-2.4.23/libraries/libldap/tls_m.c
--- openldap-2.4.23/libraries/libldap/tls_m.c 2011-01-06 20:24:54.401170400 +0100
+++ openldap-2.4.23/libraries/libldap/tls_m.c 2011-01-06 20:40:21.180097089 +0100
@@ -63,6 +63,7 @@
#include <nss/secerr.h>
#include <nss/keyhi.h>
#include <nss/secmod.h>
+#include <nss/cert.h>
/* NSS 3.12.5 and later have NSS_InitContext */
#if NSS_VMAJOR <= 3 && NSS_VMINOR <= 12 && NSS_VPATCH < 5
@@ -900,29 +901,137 @@ tlsm_pin_prompt(PK11SlotInfo *slot, PRBo
}
static SECStatus
-tlsm_auth_cert_handler(void *arg, PRFileDesc *fd,
- PRBool checksig, PRBool isServer)
+tlsm_get_basic_constraint_extension( CERTCertificate *cert,
+ CERTBasicConstraints *cbcval )
{
- SECStatus ret = SSL_AuthCertificate(arg, fd, checksig, isServer);
+ SECItem encodedVal = { 0, NULL };
+ SECStatus rc;
- if ( ret != SECSuccess ) {
- PRErrorCode errcode = PORT_GetError();
- /* we bypass NSS's hostname checks and do our own - tlsm_session_chkhost will handle it */
- if ( errcode == SSL_ERROR_BAD_CERT_DOMAIN ) {
- Debug( LDAP_DEBUG_TRACE,
- "TLS certificate verification: defer\n",
- 0, 0, 0 );
- } else {
+ rc = CERT_FindCertExtension( cert, SEC_OID_X509_BASIC_CONSTRAINTS,
+ &encodedVal);
+ if ( rc != SECSuccess ) {
+ return rc;
+ }
+
+ rc = CERT_DecodeBasicConstraintValue( cbcval, &encodedVal );
+
+ /* free the raw extension data */
+ PORT_Free( encodedVal.data );
+
+ return rc;
+}
+
+static PRBool
+tlsm_cert_is_self_issued( CERTCertificate *cert )
+{
+ /* A cert is self-issued if its subject and issuer are equal and
+ * both are of non-zero length.
+ */
+ PRBool is_self_issued = cert &&
+ (PRBool)SECITEM_ItemsAreEqual( &cert->derIssuer,
+ &cert->derSubject ) &&
+ cert->derSubject.len > 0;
+ return is_self_issued;
+}
+
+static SECStatus
+tlsm_verify_cert(CERTCertDBHandle *handle, CERTCertificate *cert, void *pinarg,
+ PRBool checksig, SECCertUsage certUsage, int errorToIgnore )
+{
+ CERTVerifyLog verifylog;
+ SECStatus ret = SECSuccess;
+ const char *name;
+
+ /* the log captures information about every cert in the chain, so we can tell
+ which cert caused the problem and what the problem was */
+ memset( &verifylog, 0, sizeof( verifylog ) );
+ verifylog.arena = PORT_NewArena( DER_DEFAULT_CHUNKSIZE );
+ if ( verifylog.arena == NULL ) {
+ Debug( LDAP_DEBUG_ANY,
+ "TLS certificate verification: Out of memory for certificate verification logger\n",
+ 0, 0, 0 );
+ return SECFailure;
+ }
+ ret = CERT_VerifyCertificate( handle, cert, checksig, certUsage, PR_Now(), pinarg, &verifylog,
+ NULL );
+ if ( ( name = cert->subjectName ) == NULL ) {
+ name = cert->nickname;
+ }
+ if ( verifylog.head == NULL ) {
+ /* it is possible for CERT_VerifyCertificate return with an error with no logging */
+ if ( ret != SECSuccess ) {
+ PRErrorCode errcode = PR_GetError();
Debug( LDAP_DEBUG_ANY,
- "TLS certificate verification: Error, %d: %s\n",
- errcode, PR_ErrorToString( errcode, PR_LANGUAGE_I_DEFAULT ), 0 ) ;
+ "TLS: certificate [%s] is not valid - error %d:%s.\n",
+ name ? name : "(unknown)",
+ errcode, PR_ErrorToString( errcode, PR_LANGUAGE_I_DEFAULT ) );
}
} else {
- Debug( LDAP_DEBUG_TRACE,
- "TLS certificate verification: ok\n",
- 0, 0, 0 );
+ const char *name;
+ CERTVerifyLogNode *node;
+
+ ret = SECSuccess; /* reset */
+ node = verifylog.head;
+ while ( node ) {
+ if ( ( name = node->cert->subjectName ) == NULL ) {
+ name = node->cert->nickname;
+ }
+ if ( node->error ) {
+ /* NSS does not like CA certs that have the basic constraints extension
+ with the CA flag set to FALSE - openssl doesn't check if the cert
+ is self issued */
+ if ( ( node->error == SEC_ERROR_CA_CERT_INVALID ) &&
+ tlsm_cert_is_self_issued( node->cert ) ) {
+ CERTBasicConstraints basicConstraint;
+ SECStatus rv = tlsm_get_basic_constraint_extension( node->cert, &basicConstraint );
+ if ( ( rv == SECSuccess ) && ( basicConstraint.isCA == PR_FALSE ) ) {
+ Debug( LDAP_DEBUG_TRACE,
+ "TLS: certificate [%s] is not correct because it is a CA cert and the "
+ "BasicConstraint CA flag is set to FALSE - allowing for now, but "
+ "please fix your certs if possible\n", name, 0, 0 );
+ } else { /* does not have basicconstraint, or some other error */
+ ret = SECFailure;
+ Debug( LDAP_DEBUG_ANY,
+ "TLS: certificate [%s] is not valid - CA cert is not valid\n",
+ name, 0, 0 );
+ }
+ } else if ( errorToIgnore && ( node->error == errorToIgnore ) ) {
+ Debug( LDAP_DEBUG_ANY,
+ "TLS: Warning: ignoring error for certificate [%s] - error %ld:%s.\n",
+ name, node->error, PR_ErrorToString( node->error, PR_LANGUAGE_I_DEFAULT ) );
+ } else {
+ ret = SECFailure;
+ Debug( LDAP_DEBUG_ANY,
+ "TLS: certificate [%s] is not valid - error %ld:%s.\n",
+ name, node->error, PR_ErrorToString( node->error, PR_LANGUAGE_I_DEFAULT ) );
+ }
+ }
+ CERT_DestroyCertificate( node->cert );
+ node = node->next;
+ }
}
+ PORT_FreeArena( verifylog.arena, PR_FALSE );
+
+ if ( ret == SECSuccess ) {
+ Debug( LDAP_DEBUG_TRACE,
+ "TLS: certificate [%s] is valid\n", name, 0, 0 );
+ }
+
+ return ret;
+}
+
+static SECStatus
+tlsm_auth_cert_handler(void *arg, PRFileDesc *fd,
+ PRBool checksig, PRBool isServer)
+{
+ SECCertUsage certUsage = isServer ? certUsageSSLClient : certUsageSSLServer;
+ SECStatus ret = SECSuccess;
+
+ ret = tlsm_verify_cert( (CERTCertDBHandle *)arg, SSL_PeerCertificate( fd ),
+ SSL_RevealPinArg( fd ),
+ checksig, certUsage, 0 );
+
return ret;
}
@@ -1017,7 +1126,7 @@ tlsm_free_pem_objs( tlsm_ctx *ctx )
}
static int
-tlsm_add_cert_from_file( tlsm_ctx *ctx, const char *filename, PRBool isca )
+tlsm_add_cert_from_file( tlsm_ctx *ctx, const char *filename, PRBool isca, PRBool istrusted )
{
CK_SLOT_ID slotID;
PK11SlotInfo *slot = NULL;
@@ -1059,9 +1168,14 @@ tlsm_add_cert_from_file( tlsm_ctx *ctx,
slotID = 0; /* CA and trust objects use slot 0 */
PR_snprintf( tmpslotname, sizeof(tmpslotname), TLSM_PEM_TOKEN_FMT, slotID );
slotname = tmpslotname;
+ istrusted = PR_TRUE;
} else {
if ( ctx->tc_slotname == NULL ) { /* need new slot */
- slotID = ++tlsm_slot_count;
+ if ( istrusted ) {
+ slotID = 0;
+ } else {
+ slotID = ++tlsm_slot_count;
+ }
ctx->tc_slotname = PR_smprintf( TLSM_PEM_TOKEN_FMT, slotID );
}
slotname = ctx->tc_slotname;
@@ -1069,7 +1183,15 @@ tlsm_add_cert_from_file( tlsm_ctx *ctx,
if ( ( ptr = PL_strrchr( filename, sep ) ) ) {
PL_strfree( ctx->tc_certname );
++ptr;
- ctx->tc_certname = PR_smprintf( "%s:%s", slotname, ptr );
+ if ( istrusted ) {
+ /* pemnss conflates trusted certs with CA certs - since there can
+ be more than one CA cert in a file (e.g. ca-bundle.crt) pemnss
+ numbers each trusted cert - in the case of a server cert, there will be
+ only one, so it will be number 0 */
+ ctx->tc_certname = PR_smprintf( "%s:%s - 0", slotname, ptr );
+ } else {
+ ctx->tc_certname = PR_smprintf( "%s:%s", slotname, ptr );
+ }
}
}
@@ -1087,7 +1209,7 @@ tlsm_add_cert_from_file( tlsm_ctx *ctx,
PK11_SETATTRS( attrs, CKA_CLASS, &objClass, sizeof(objClass) ); attrs++;
PK11_SETATTRS( attrs, CKA_TOKEN, &cktrue, sizeof(CK_BBOOL) ); attrs++;
PK11_SETATTRS( attrs, CKA_LABEL, (unsigned char *)filename, strlen(filename)+1 ); attrs++;
- if ( isca ) {
+ if ( istrusted ) {
PK11_SETATTRS( attrs, CKA_TRUST, &cktrue, sizeof(CK_BBOOL) ); attrs++;
} else {
PK11_SETATTRS( attrs, CKA_TRUST, &ckfalse, sizeof(CK_BBOOL) ); attrs++;
@@ -1204,7 +1326,7 @@ tlsm_init_ca_certs( tlsm_ctx *ctx, const
}
if ( cacertfile ) {
- int rc = tlsm_add_cert_from_file( ctx, cacertfile, isca );
+ int rc = tlsm_add_cert_from_file( ctx, cacertfile, isca, PR_TRUE );
if ( rc ) {
errcode = PR_GetError();
Debug( LDAP_DEBUG_ANY,
@@ -1268,7 +1390,7 @@ tlsm_init_ca_certs( tlsm_ctx *ctx, const
continue;
}
fullpath = PR_smprintf( "%s/%s", cacertdir, entry->name );
- if ( !tlsm_add_cert_from_file( ctx, fullpath, isca ) ) {
+ if ( !tlsm_add_cert_from_file( ctx, fullpath, isca, PR_TRUE ) ) {
Debug( LDAP_DEBUG_TRACE,
"TLS: loaded CA certificate file %s from CA certificate directory %s.\n",
fullpath, cacertdir, 0 );
@@ -1627,45 +1749,11 @@ tlsm_find_and_verify_cert_key(tlsm_ctx *
} else {
checkSig = PR_FALSE;
}
- status = CERT_VerifyCertificateNow( ctx->tc_certdb, cert,
- checkSig, certUsage,
- pin_arg, NULL );
- if ( status != SECSuccess ) {
- /* NSS doesn't like self-signed CA certs that are also used for
- TLS/SSL server certs (such as generated by openssl req -x509)
- CERT_VerifyCertificateNow returns SEC_ERROR_UNTRUSTED_ISSUER in that case
- so, see if the cert and issuer are the same cert
- */
- PRErrorCode errcode = PR_GetError();
-
- if ( errcode == SEC_ERROR_UNTRUSTED_ISSUER ) {
- CERTCertificate *issuer = CERT_FindCertIssuer( cert, PR_Now(), certUsageSSLServer );
- if ( NULL == issuer ) {
- /* no issuer - warn and allow */
- status = SECSuccess;
- rc = 0;
- Debug( LDAP_DEBUG_ANY,
- "TLS: warning: the server certificate %s has no issuer - "
- "please check this certificate for validity\n",
- certname, 0, 0 );
- } else if ( CERT_CompareCerts( cert, issuer ) ) {
- /* self signed - warn and allow */
- status = SECSuccess;
- rc = 0;
- Debug( LDAP_DEBUG_ANY,
- "TLS: warning: using self-signed server certificate %s\n",
- certname, 0, 0 );
- }
- CERT_DestroyCertificate( issuer );
- }
-
- if ( status != SECSuccess ) {
- Debug( LDAP_DEBUG_ANY,
- "TLS: error: the certificate %s is not valid - error %d:%s\n",
- certname, errcode, PR_ErrorToString( errcode, PR_LANGUAGE_I_DEFAULT ) );
- }
- } else {
- rc = 0; /* success */
+ /* may not have a CA cert - ok - ignore SEC_ERROR_UNKNOWN_ISSUER */
+ status = tlsm_verify_cert( ctx->tc_certdb, cert, pin_arg,
+ checkSig, certUsage, SEC_ERROR_UNKNOWN_ISSUER );
+ if ( status == SECSuccess ) {
+ rc = 0;
}
} else {
PRErrorCode errcode = PR_GetError();
@@ -1963,7 +2051,7 @@ tlsm_deferred_ctx_init( void *arg )
/* otherwise, assume this is the name of a cert already in the db */
if ( ctx->tc_using_pem ) {
/* this sets ctx->tc_certname to the correct value */
- int rc = tlsm_add_cert_from_file( ctx, lt->lt_certfile, PR_FALSE /* not a ca */ );
+ int rc = tlsm_add_cert_from_file( ctx, lt->lt_certfile, PR_FALSE, PR_TRUE );
if ( rc ) {
return rc;
}
@@ -2291,8 +2379,8 @@ static char *
tlsm_session_errmsg( tls_session *sess, int rc, char *buf, size_t len )
{
int i;
+ int prerror = PR_GetError();
- rc = PR_GetError();
i = PR_GetErrorTextLength();
if ( i > len ) {
char *msg = LDAP_MALLOC( i+1 );
@@ -2301,9 +2389,12 @@ tlsm_session_errmsg( tls_session *sess,
LDAP_FREE( msg );
} else if ( i ) {
PR_GetErrorText( buf );
+ } else if ( prerror ) {
+ i = PR_snprintf( buf, len, "TLS error %d:%s",
+ prerror, PR_ErrorToString( prerror, PR_LANGUAGE_I_DEFAULT ) );
}
- return i ? buf : NULL;
+ return ( i > 0 ) ? buf : NULL;
}
static int

3
openldap.spec
View File

@ -36,8 +36,8 @@ Patch103: openldap-reject-non-file-keyfiles.patch
Patch104: openldap-use-cacert-dir-and-file.patch
Patch105: openldap-cacertdir-hash-only.patch
Patch106: openldap-improve-trace-messages.patch
# patches sent upstream
Patch107: openldap-nss-non-blocking.patch
Patch108: openldap-verify-self-issued-certs.patch
# patches for the evolution library (see README.evolution)
Patch200: openldap-evolution-ntlm.patch
@ -147,6 +147,7 @@ pushd openldap-%{version}
%patch105 -p1 -b .cacertdir-hash-only
%patch106 -p1 -b .improve-trace-messages
%patch107 -p1 -b .nss-non-blocking
%patch108 -p1 -b .verify-self-issued-certs
cp %{_datadir}/libtool/config/config.{sub,guess} build/