Implement remaining OCSP verify checks in
authorDr. Stephen Henson <steve@openssl.org>
Thu, 18 Jan 2001 01:35:39 +0000 (01:35 +0000)
committerDr. Stephen Henson <steve@openssl.org>
Thu, 18 Jan 2001 01:35:39 +0000 (01:35 +0000)
accordance with RFC2560.

CHANGES
apps/ocsp.c
crypto/ocsp/ocsp.h
crypto/ocsp/ocsp_err.c
crypto/ocsp/ocsp_vfy.c

diff --git a/CHANGES b/CHANGES
index 569f8ce..dedd7c3 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,16 @@
 
  Changes between 0.9.6 and 0.9.7  [xx XXX 2000]
 
+  *) Add additional OCSP certificate checks. These are those specified
+     in RFC2560. This consists of two separate checks: the CA of the
+     certificate being checked must either be the OCSP signer certificate
+     or the issuer of the OCSP signer certificate. In the latter case the
+     OCSP signer certificate must contain the OCSP signing extended key
+     usage. This check is performed by attempting to match the OCSP
+     signer or the OCSP signer CA to the issuerNameHash and issuerKeyHash
+     in the OCSP_CERTID structures of the response.
+     [Steve Henson]
+
   *) Initial OCSP certificate verification added to OCSP_basic_verify()
      and related routines. This uses the standard OpenSSL certificate
      verify routines to perform initial checks (just CA validity) and
index 3125583..bea16eb 100644 (file)
@@ -420,6 +420,8 @@ int MAIN(int argc, char **argv)
                BIO_printf(bio_err, "Response verify error (%d)\n", i);
                ERR_print_errors(bio_err);
                }
+       else
+               BIO_printf(bio_err, "Response verify OK\n");
 
        ret = 0;
 
index 1cb6ead..ef36ba9 100644 (file)
@@ -561,7 +561,11 @@ void ERR_load_OCSP_strings(void);
 #define OCSP_F_CERT_STATUS_NEW                          103
 #define OCSP_F_D2I_OCSP_NONCE                           109
 #define OCSP_F_OCSP_BASIC_VERIFY                        113
+#define OCSP_F_OCSP_CHECK_DELEGATED                     117
+#define OCSP_F_OCSP_CHECK_IDS                           114
+#define OCSP_F_OCSP_CHECK_ISSUER                        115
 #define OCSP_F_OCSP_CHECK_NONCE                                 112
+#define OCSP_F_OCSP_MATCH_ISSUERID                      116
 #define OCSP_F_OCSP_RESPONSE_GET1_BASIC                         111
 #define OCSP_F_OCSP_SENDREQ_BIO                                 110
 #define OCSP_F_REQUEST_VERIFY                           104
@@ -577,15 +581,18 @@ void ERR_load_OCSP_strings(void);
 #define OCSP_R_FAILED_TO_OPEN                           109
 #define OCSP_R_FAILED_TO_READ                           110
 #define OCSP_R_FAILED_TO_STAT                           111
+#define OCSP_R_MISSING_OCSPSIGNING_USAGE                131
 #define OCSP_R_MISSING_VALUE                            112
 #define OCSP_R_NONCE_MISSING_IN_RESPONSE                121
 #define OCSP_R_NONCE_VALUE_MISMATCH                     122
 #define OCSP_R_NOT_BASIC_RESPONSE                       120
 #define OCSP_R_NO_CERTIFICATE                           102
+#define OCSP_R_NO_CERTIFICATES_IN_CHAIN                         128
 #define OCSP_R_NO_CONTENT                               115
 #define OCSP_R_NO_PUBLIC_KEY                            103
 #define OCSP_R_NO_RESPONSE_DATA                                 104
 #define OCSP_R_NO_SIGNATURE                             105
+#define OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA     129
 #define OCSP_R_REVOKED_NO_TIME                          106
 #define OCSP_R_ROOT_CA_NOT_TRUSTED                      127
 #define OCSP_R_SERVER_READ_ERROR                        116
@@ -595,6 +602,7 @@ void ERR_load_OCSP_strings(void);
 #define OCSP_R_SIGNATURE_FAILURE                        124
 #define OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND             125
 #define OCSP_R_UNEXPECTED_NONCE_IN_RESPONSE             123
+#define OCSP_R_UNKNOWN_MESSAGE_DIGEST                   130
 #define OCSP_R_UNKNOWN_NID                              107
 #define OCSP_R_UNSUPPORTED_OPTION                       113
 #define OCSP_R_VALUE_ALREADY                            114
index f4335d2..b860872 100644 (file)
@@ -73,7 +73,11 @@ static ERR_STRING_DATA OCSP_str_functs[]=
 {ERR_PACK(0,OCSP_F_CERT_STATUS_NEW,0), "CERT_STATUS_NEW"},
 {ERR_PACK(0,OCSP_F_D2I_OCSP_NONCE,0),  "D2I_OCSP_NONCE"},
 {ERR_PACK(0,OCSP_F_OCSP_BASIC_VERIFY,0),       "OCSP_basic_verify"},
+{ERR_PACK(0,OCSP_F_OCSP_CHECK_DELEGATED,0),    "OCSP_CHECK_DELEGATED"},
+{ERR_PACK(0,OCSP_F_OCSP_CHECK_IDS,0),  "OCSP_CHECK_IDS"},
+{ERR_PACK(0,OCSP_F_OCSP_CHECK_ISSUER,0),       "OCSP_CHECK_ISSUER"},
 {ERR_PACK(0,OCSP_F_OCSP_CHECK_NONCE,0),        "OCSP_check_nonce"},
+{ERR_PACK(0,OCSP_F_OCSP_MATCH_ISSUERID,0),     "OCSP_MATCH_ISSUERID"},
 {ERR_PACK(0,OCSP_F_OCSP_RESPONSE_GET1_BASIC,0),        "OCSP_response_get1_basic"},
 {ERR_PACK(0,OCSP_F_OCSP_SENDREQ_BIO,0),        "OCSP_sendreq_bio"},
 {ERR_PACK(0,OCSP_F_REQUEST_VERIFY,0),  "REQUEST_VERIFY"},
@@ -92,15 +96,18 @@ static ERR_STRING_DATA OCSP_str_reasons[]=
 {OCSP_R_FAILED_TO_OPEN                   ,"failed to open"},
 {OCSP_R_FAILED_TO_READ                   ,"failed to read"},
 {OCSP_R_FAILED_TO_STAT                   ,"failed to stat"},
+{OCSP_R_MISSING_OCSPSIGNING_USAGE        ,"missing ocspsigning usage"},
 {OCSP_R_MISSING_VALUE                    ,"missing value"},
 {OCSP_R_NONCE_MISSING_IN_RESPONSE        ,"nonce missing in response"},
 {OCSP_R_NONCE_VALUE_MISMATCH             ,"nonce value mismatch"},
 {OCSP_R_NOT_BASIC_RESPONSE               ,"not basic response"},
 {OCSP_R_NO_CERTIFICATE                   ,"no certificate"},
+{OCSP_R_NO_CERTIFICATES_IN_CHAIN         ,"no certificates in chain"},
 {OCSP_R_NO_CONTENT                       ,"no content"},
 {OCSP_R_NO_PUBLIC_KEY                    ,"no public key"},
 {OCSP_R_NO_RESPONSE_DATA                 ,"no response data"},
 {OCSP_R_NO_SIGNATURE                     ,"no signature"},
+{OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA,"response contains no revocation data"},
 {OCSP_R_REVOKED_NO_TIME                  ,"revoked no time"},
 {OCSP_R_ROOT_CA_NOT_TRUSTED              ,"root ca not trusted"},
 {OCSP_R_SERVER_READ_ERROR                ,"server read error"},
@@ -110,6 +117,7 @@ static ERR_STRING_DATA OCSP_str_reasons[]=
 {OCSP_R_SIGNATURE_FAILURE                ,"signature failure"},
 {OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND     ,"signer certificate not found"},
 {OCSP_R_UNEXPECTED_NONCE_IN_RESPONSE     ,"unexpected nonce in response"},
+{OCSP_R_UNKNOWN_MESSAGE_DIGEST           ,"unknown message digest"},
 {OCSP_R_UNKNOWN_NID                      ,"unknown nid"},
 {OCSP_R_UNSUPPORTED_OPTION               ,"unsupported option"},
 {OCSP_R_VALUE_ALREADY                    ,"value already"},
index 6110825..b656609 100644 (file)
 static X509 *ocsp_find_signer(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
                                X509_STORE *st, unsigned long flags);
 static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id);
+static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags);
+static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret);
+static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid, STACK_OF(OCSP_SINGLERESP) *sresp);
+static int ocsp_check_delegated(X509 *x, int flags);
 
 /* Verify a basic response message */
 
@@ -78,7 +82,7 @@ int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
                OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_SIGNER_CERTIFICATE_NOT_FOUND);
                goto end;
                }
-       if(!(flags & OCSP_NOSIGS))
+       if (!(flags & OCSP_NOSIGS))
                {
                EVP_PKEY *skey;
                skey = X509_get_pubkey(signer);
@@ -90,7 +94,7 @@ int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
                        goto end;
                        }
                }
-       if(!(flags & OCSP_NOVERIFY))
+       if (!(flags & OCSP_NOVERIFY))
                {
                if(flags & OCSP_NOCHAIN)
                        X509_STORE_CTX_init(&ctx, st, signer, NULL);
@@ -115,15 +119,12 @@ int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
                        goto end;
                        }
                /* At this point we have a valid certificate chain
-                * need to verify it against the OCSP criteria.
+                * need to verify it against the OCSP issuer criteria.
                 */
-#if 0
-               if(ocsp_check_issuer(bs, chain, flags))
-                       {
-                       ret = 1;
-                       goto end;
-                       }
-#endif
+               ret = ocsp_check_issuer(bs, chain, flags);
+
+               /* If fatal error or valid match then finish */
+               if (ret != 0) goto end;
 
                /* Easy case: explicitly trusted. Get root CA and
                 * check for explicit trust
@@ -172,16 +173,16 @@ static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
        X509 *x;
 
        /* Easy if lookup by name */
-       if(id->type == V_OCSP_RESPID_NAME)
+       if (id->type == V_OCSP_RESPID_NAME)
                return X509_find_by_subject(certs, id->value.byName);
 
        /* Lookup by key hash */
 
        /* If key hash isn't SHA1 length then forget it */
-       if(id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
+       if (id->value.byKey->length != SHA_DIGEST_LENGTH) return NULL;
        keyhash = id->value.byKey->data;
        /* Calculate hash of each key and compare */
-       for(i = 0; i < sk_X509_num(certs); i++)
+       for (i = 0; i < sk_X509_num(certs); i++)
                {
                x = sk_X509_value(certs, i);
                key = x->cert_info->key->public_key;
@@ -195,3 +196,148 @@ static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
        }
 
 
+static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain, unsigned long flags)
+       {
+       STACK_OF(OCSP_SINGLERESP) *sresp;
+       X509 *signer, *sca;
+       OCSP_CERTID *caid = NULL;
+       int i;
+       sresp = bs->tbsResponseData->responses;
+
+       if (sk_X509_num(chain) <= 0)
+               {
+               OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
+               return -1;
+               }
+
+       /* See if the issuer IDs match. */
+       i = ocsp_check_ids(sresp, &caid);
+
+       /* If ID mismatch or other error then return */
+       if (i <= 0) return i;
+
+       signer = sk_X509_value(chain, 0);
+       /* Check to see if OCSP responder CA matches request CA */
+       if (sk_X509_num(chain) > 1)
+               {
+               sca = sk_X509_value(chain, 1);
+               i = ocsp_match_issuerid(sca, caid, sresp);
+               if (i < 0) return i;
+               if (i)
+                       {
+                       /* We have a match, if extensions OK then success */
+                       if (ocsp_check_delegated(signer, flags)) return 1;
+                       return 0;
+                       }
+               }
+
+       /* Otherwise check if OCSP request signed directly by request CA */
+       return ocsp_match_issuerid(signer, caid, sresp);
+       }
+
+
+/* Check the issuer certificate IDs for equality. If there is a mismatch with the same
+ * algorithm then there's no point trying to match any certificates against the issuer.
+ * If the issuer IDs all match then we just need to check equality against one of them.
+ */
+       
+static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
+       {
+       OCSP_CERTID *tmpid, *cid;
+       int i, idcount;
+
+       idcount = sk_OCSP_SINGLERESP_num(sresp);
+       if (idcount <= 0)
+               {
+               OCSPerr(OCSP_F_OCSP_CHECK_IDS, OCSP_R_RESPONSE_CONTAINS_NO_REVOCATION_DATA);
+               return -1;
+               }
+
+       cid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
+
+       *ret = NULL;
+
+       for (i = 1; i < idcount; i++)
+               {
+               tmpid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
+               /* Check to see if IDs match */
+               if (OCSP_id_issuer_cmp(cid, tmpid))
+                       {
+                       /* If algoritm mismatch let caller deal with it */
+                       if (OBJ_cmp(tmpid->hashAlgorithm->algorithm,
+                                       cid->hashAlgorithm->algorithm))
+                                       return 2;
+                       /* Else mismatch */
+                       return 0;
+                       }
+               }
+
+       /* All IDs match: only need to check one ID */
+       *ret = cid;
+       return 1;
+       }
+
+
+static int ocsp_match_issuerid(X509 *cert, OCSP_CERTID *cid,
+                       STACK_OF(OCSP_SINGLERESP) *sresp)
+       {
+       /* If only one ID to match then do it */
+       if(cid)
+               {
+               const EVP_MD *dgst;
+               EVP_MD_CTX ctx;
+               X509_NAME *iname;
+               ASN1_BIT_STRING *ikey;
+               int mdlen;
+               unsigned char md[EVP_MAX_MD_SIZE];
+               if (!(dgst = EVP_get_digestbyobj(cid->hashAlgorithm->algorithm)))
+                       {
+                       OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
+                       return -1;
+                       }
+
+               mdlen = EVP_MD_size(dgst);
+               if ((cid->issuerNameHash->length != mdlen) ||
+                  (cid->issuerKeyHash->length != mdlen))
+                       return 0;
+               iname = X509_get_issuer_name(cert);
+               if (!X509_NAME_digest(iname, dgst, md, NULL))
+                       return -1;
+               if (memcmp(md, cid->issuerNameHash->data, mdlen))
+                       return 0;
+               ikey = cert->cert_info->key->public_key;
+
+               EVP_DigestInit(&ctx,dgst);
+               EVP_DigestUpdate(&ctx,ikey->data, ikey->length);
+               EVP_DigestFinal(&ctx,md,NULL);
+               if (memcmp(md, cid->issuerKeyHash->data, mdlen))
+                       return 0;
+
+               return 1;
+
+               }
+       else
+               {
+               /* We have to match the whole lot */
+               int i, ret;
+               OCSP_CERTID *tmpid;
+               for (i = 0; i < sk_OCSP_SINGLERESP_num(sresp); i++)
+                       {
+                       tmpid = sk_OCSP_SINGLERESP_value(sresp, 0)->certId;
+                       ret = ocsp_match_issuerid(cert, tmpid, NULL);
+                       if (ret <= 0) return ret;
+                       }
+               return 1;
+               }
+                       
+       }
+
+static int ocsp_check_delegated(X509 *x, int flags)
+       {
+       X509_check_purpose(x, -1, 0);
+       if ((x->ex_flags & EXFLAG_XKUSAGE) &&
+           (x->ex_xkusage & XKU_OCSP_SIGN))
+               return 1;
+       OCSPerr(OCSP_F_OCSP_CHECK_DELEGATED, OCSP_R_MISSING_OCSPSIGNING_USAGE);
+       return 0;
+       }