Perform DANE-EE(3) name checks by default
[oweals/openssl.git] / crypto / x509 / x509_vfy.c
index fe0ea988265e3d083e519ec58633cbf0b8f1274e..ee1c9af977509f104fccc44e7385a87a263c00f2 100644 (file)
@@ -251,9 +251,11 @@ static int verify_chain(X509_STORE_CTX *ctx)
 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;
     }
 
@@ -263,6 +265,7 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
          * 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;
     }
 
@@ -273,6 +276,7 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
     if (((ctx->chain = sk_X509_new_null()) == NULL) ||
         (!sk_X509_push(ctx->chain, ctx->cert))) {
         X509err(X509_F_X509_VERIFY_CERT, ERR_R_MALLOC_FAILURE);
+        ctx->error = X509_V_ERR_OUT_OF_MEM;
         return -1;
     }
     X509_up_ref(ctx->cert);
@@ -283,15 +287,19 @@ int X509_verify_cert(X509_STORE_CTX *ctx)
         !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);
+
     /*
-     * If dane->trecs is an empty stack, we'll fail, since the user enabled
-     * DANE.  If none of the TLSA records were usable, and it makes sense to
-     * keep going with an unauthenticated handshake, they can handle that in
-     * the verify callback, or not set SSL_VERIFY_PEER.
+     * 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 (DANETLS_ENABLED(dane))
-        return dane_verify(ctx);
-    return verify_chain(ctx);
+    if (ret <= 0 && ctx->error == X509_V_OK)
+        ctx->error = X509_V_ERR_UNSPECIFIED;
+    return ret;
 }
 
 /*
@@ -453,12 +461,6 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
     } else {
         allow_proxy_certs =
             ! !(ctx->param->flags & X509_V_FLAG_ALLOW_PROXY_CERTS);
-        /*
-         * A hack to keep people who don't want to modify their software
-         * happy
-         */
-        if (getenv("OPENSSL_ALLOW_PROXY_CERTS"))
-            allow_proxy_certs = 1;
         purpose = ctx->param->purpose;
     }
 
@@ -525,10 +527,24 @@ static int check_chain_extensions(X509_STORE_CTX *ctx)
          * the next certificate must be a CA certificate.
          */
         if (x->ex_flags & EXFLAG_PROXY) {
-            if (x->ex_pcpathlen != -1 && i > x->ex_pcpathlen) {
-                if (!verify_cb_cert(ctx, x, i,
-                                    X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED))
-                    return 0;
+            /*
+             * 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;
@@ -550,6 +566,79 @@ static int check_name_constraints(X509_STORE_CTX *ctx)
         /* 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
@@ -562,8 +651,20 @@ static int check_name_constraints(X509_STORE_CTX *ctx)
             if (nc) {
                 int rv = NAME_CONSTRAINTS_check(x, nc);
 
-                if (rv != X509_V_OK && !verify_cb_cert(ctx, x, i, rv))
+                /* If EE certificate check commonName too */
+                if (rv == X509_V_OK && i == 0)
+                    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;
+                }
             }
         }
     }
@@ -1457,6 +1558,7 @@ static int check_policy(X509_STORE_CTX *ctx)
      */
     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,
@@ -1466,6 +1568,7 @@ static int check_policy(X509_STORE_CTX *ctx)
 
     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 */
@@ -1496,7 +1599,12 @@ static int check_policy(X509_STORE_CTX *ctx)
 
     if (ctx->param->flags & X509_V_FLAG_NOTIFY_POLICY) {
         ctx->current_cert = NULL;
-        ctx->error = X509_V_OK;
+        /*
+         * 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;
     }
@@ -2172,12 +2280,12 @@ int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
     if (store && store->lookup_certs)
         ctx->lookup_certs = store->lookup_certs;
     else
-        ctx->lookup_certs = X509_STORE_get1_certs;
+        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_get1_crls;
+        ctx->lookup_crls = X509_STORE_CTX_get1_crls;
 
     ctx->check_policy = check_policy;
 
@@ -2428,7 +2536,7 @@ static int dane_match(X509_STORE_CTX *ctx, X509 *cert, int depth)
 
     /*
      * If we've previously matched a PKIX-?? record, no need to test any
-     * further PKIX-?? records,  it remains to just build the PKIX chain.
+     * 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)
@@ -2657,6 +2765,10 @@ static int dane_verify(X509_STORE_CTX *ctx)
         /* 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;
@@ -2742,6 +2854,7 @@ static int build_chain(X509_STORE_CTX *ctx)
      */
     if (ctx->untrusted && (sktmp = sk_X509_dup(ctx->untrusted)) == NULL) {
         X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
+        ctx->error = X509_V_ERR_OUT_OF_MEM;
         return 0;
     }
 
@@ -2758,12 +2871,14 @@ static int build_chain(X509_STORE_CTX *ctx)
     if (DANETLS_ENABLED(dane) && dane->certs != NULL) {
         if (sktmp == NULL && (sktmp = sk_X509_new_null()) == NULL) {
             X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
+            ctx->error = X509_V_ERR_OUT_OF_MEM;
             return 0;
         }
         for (i = 0; i < sk_X509_num(dane->certs); ++i) {
             if (!sk_X509_push(sktmp, sk_X509_value(dane->certs, i))) {
                 sk_X509_free(sktmp);
                 X509err(X509_F_BUILD_CHAIN, ERR_R_MALLOC_FAILURE);
+                ctx->error = X509_V_ERR_OUT_OF_MEM;
                 return 0;
             }
         }
@@ -2827,6 +2942,7 @@ static int build_chain(X509_STORE_CTX *ctx)
 
             if (ok < 0) {
                 trust = X509_TRUST_REJECTED;
+                ctx->error = X509_V_ERR_STORE_LOOKUP;
                 search = 0;
                 continue;
             }
@@ -2873,6 +2989,7 @@ static int build_chain(X509_STORE_CTX *ctx)
                         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;
                     }
@@ -2969,6 +3086,7 @@ static int build_chain(X509_STORE_CTX *ctx)
             if (!sk_X509_push(ctx->chain, 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;
             }