OCSP: Add return value checks.

The calls are unlikely to fail but better checking their return than not.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/12648)

crypto/err/openssl.txt

@@ -2678,6 +2678,8 @@ OBJ_R_UNKNOWN_NID:101:unknown nid
 OBJ_R_UNKNOWN_OBJECT_NAME:103:unknown object name
 OCSP_R_CERTIFICATE_VERIFY_ERROR:101:certificate verify error
 OCSP_R_DIGEST_ERR:102:digest err
+OCSP_R_DIGEST_NAME_ERR:106:digest name err
+OCSP_R_DIGEST_SIZE_ERR:107:digest size err
 OCSP_R_ERROR_IN_NEXTUPDATE_FIELD:122:error in nextupdate field
 OCSP_R_ERROR_IN_THISUPDATE_FIELD:123:error in thisupdate field
 OCSP_R_MISSING_OCSPSIGNING_USAGE:103:missing ocspsigning usage

crypto/ocsp/ocsp_err.c

@@ -17,6 +17,8 @@ static const ERR_STRING_DATA OCSP_str_reasons[] = {
     {ERR_PACK(ERR_LIB_OCSP, 0, OCSP_R_CERTIFICATE_VERIFY_ERROR),
     "certificate verify error"},
     {ERR_PACK(ERR_LIB_OCSP, 0, OCSP_R_DIGEST_ERR), "digest err"},
+    {ERR_PACK(ERR_LIB_OCSP, 0, OCSP_R_DIGEST_NAME_ERR), "digest name err"},
+    {ERR_PACK(ERR_LIB_OCSP, 0, OCSP_R_DIGEST_SIZE_ERR), "digest size err"},
     {ERR_PACK(ERR_LIB_OCSP, 0, OCSP_R_ERROR_IN_NEXTUPDATE_FIELD),
     "error in nextupdate field"},
     {ERR_PACK(ERR_LIB_OCSP, 0, OCSP_R_ERROR_IN_THISUPDATE_FIELD),

crypto/ocsp/ocsp_vfy.c

@@ -54,6 +54,7 @@ int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
         flags |= OCSP_NOVERIFY;
     if (!(flags & OCSP_NOSIGS)) {
         EVP_PKEY *skey;
+
         skey = X509_get0_pubkey(signer);
         if (skey == NULL) {
             OCSPerr(OCSP_F_OCSP_BASIC_VERIFY, OCSP_R_NO_SIGNER_KEY);
@@ -153,6 +154,7 @@ static int ocsp_find_signer(X509 **psigner, OCSP_BASICRESP *bs,
 {
     X509 *signer;
     OCSP_RESPID *rid = &bs->tbsResponseData.responderId;
+
     if ((signer = ocsp_find_signer_sk(certs, rid))) {
         *psigner = signer;
         return 2;
@@ -187,8 +189,9 @@ static X509 *ocsp_find_signer_sk(STACK_OF(X509) *certs, OCSP_RESPID *id)
     /* Calculate hash of each key and compare */
     for (i = 0; i < sk_X509_num(certs); i++) {
         x = sk_X509_value(certs, i);
-        X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL);
+        if (!X509_pubkey_digest(x, EVP_sha1(), tmphash, NULL))
-        if (!memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH))
+            break;
+        if (memcmp(keyhash, tmphash, SHA_DIGEST_LENGTH) == 0)
             return x;
     }
     return NULL;
@@ -200,8 +203,8 @@ static int ocsp_check_issuer(OCSP_BASICRESP *bs, STACK_OF(X509) *chain)
     X509 *signer, *sca;
     OCSP_CERTID *caid = NULL;
     int i;
-    sresp = bs->tbsResponseData.responses;
 
+    sresp = bs->tbsResponseData.responses;
     if (sk_X509_num(chain) <= 0) {
         OCSPerr(OCSP_F_OCSP_CHECK_ISSUER, OCSP_R_NO_CERTIFICATES_IN_CHAIN);
         return -1;
@@ -274,52 +277,60 @@ static int ocsp_check_ids(STACK_OF(OCSP_SINGLERESP) *sresp, OCSP_CERTID **ret)
     return 1;
 }
 
+/*
+ * Match the certificate issuer ID.
+ * Returns -1 on error, 0 if there is no match and 1 if there is a match.
+ */
 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) {
+    if (cid != NULL) {
         const EVP_MD *dgst;
         const X509_NAME *iname;
         int mdlen;
         unsigned char md[EVP_MAX_MD_SIZE];
-        if ((dgst = EVP_get_digestbyobj(cid->hashAlgorithm.algorithm))
+
-                == NULL) {
+        dgst = EVP_get_digestbyobj(cid->hashAlgorithm.algorithm);
-            OCSPerr(OCSP_F_OCSP_MATCH_ISSUERID,
+        if (dgst == NULL) {
-                    OCSP_R_UNKNOWN_MESSAGE_DIGEST);
+            OCSPerr(0, OCSP_R_UNKNOWN_MESSAGE_DIGEST);
             return -1;
         }
 
         mdlen = EVP_MD_size(dgst);
-        if (mdlen < 0)
+        if (mdlen < 0) {
+            OCSPerr(0, OCSP_R_DIGEST_SIZE_ERR);
             return -1;
-        if ((cid->issuerNameHash.length != mdlen) ||
+        }
-            (cid->issuerKeyHash.length != mdlen))
+        if (cid->issuerNameHash.length != mdlen ||
+            cid->issuerKeyHash.length != mdlen)
             return 0;
         iname = X509_get_subject_name(cert);
-        if (!X509_NAME_digest(iname, dgst, md, NULL))
+        if (!X509_NAME_digest(iname, dgst, md, NULL)) {
+            OCSPerr(0, OCSP_R_DIGEST_NAME_ERR);
             return -1;
-        if (memcmp(md, cid->issuerNameHash.data, mdlen))
+        }
+        if (memcmp(md, cid->issuerNameHash.data, mdlen) != 0)
             return 0;
-        X509_pubkey_digest(cert, dgst, md, NULL);
+        if (!X509_pubkey_digest(cert, dgst, md, NULL)) {
-        if (memcmp(md, cid->issuerKeyHash.data, mdlen))
+            OCSPerr(0, OCSP_R_DIGEST_ERR);
+            return -1;
+        }
+        if (memcmp(md, cid->issuerKeyHash.data, mdlen) != 0)
             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, i)->certId;
             ret = ocsp_match_issuerid(cert, tmpid, NULL);
             if (ret <= 0)
                 return ret;
         }
-        return 1;
     }
-
+    return 1;
 }
 
 static int ocsp_check_delegated(X509 *x)
@@ -381,6 +392,7 @@ int OCSP_request_verify(OCSP_REQUEST *req, STACK_OF(X509) *certs,
     }
     if (!(flags & OCSP_NOVERIFY)) {
         int init_res;
+
         if (flags & OCSP_NOCHAIN)
             init_res = X509_STORE_CTX_init(ctx, store, signer, NULL);
         else
@@ -419,6 +431,7 @@ static int ocsp_req_find_signer(X509 **psigner, OCSP_REQUEST *req,
                                 unsigned long flags)
 {
     X509 *signer;
+
     if (!(flags & OCSP_NOINTERN)) {
         signer = X509_find_by_subject(req->optionalSignature->certs, nm);
         if (signer) {

include/openssl/ocsperr.h

@@ -50,6 +50,8 @@ int ERR_load_OCSP_strings(void);
  */
 #  define OCSP_R_CERTIFICATE_VERIFY_ERROR                  101
 #  define OCSP_R_DIGEST_ERR                                102
+#  define OCSP_R_DIGEST_NAME_ERR                           106
+#  define OCSP_R_DIGEST_SIZE_ERR                           107
 #  define OCSP_R_ERROR_IN_NEXTUPDATE_FIELD                 122
 #  define OCSP_R_ERROR_IN_THISUPDATE_FIELD                 123
 #  define OCSP_R_MISSING_OCSPSIGNING_USAGE                 103