Prevent a CA from the peer's chain from being used to satisfy the NameConstraints check.

certs/test/include.am

@@ -121,9 +121,16 @@ EXTRA_DIST += \
          certs/test/nc-ancestor/00-uri-permit-ca-permissive-key.pem \
          certs/test/nc-ancestor/01-uri-permit-ca-cert.pem \
          certs/test/nc-ancestor/01-uri-permit-ca-key.pem \
+         certs/test/nc-ancestor/01-uri-permit-ca-selfissued-cert.pem \
+         certs/test/nc-ancestor/01-uri-permit-ca-selfloop-cert.pem \
+         certs/test/nc-ancestor/01-uri-permit-ca-selfloop-key.pem \
          certs/test/nc-ancestor/02-benign-sub-ca-cert.pem \
          certs/test/nc-ancestor/02-benign-sub-ca-key.pem \
          certs/test/nc-ancestor/03-leaf-attacker-key.pem \
          certs/test/nc-ancestor/03-leaf-chain.pem \
+         certs/test/nc-ancestor/03-selfissued-leaf-cert.pem \
+         certs/test/nc-ancestor/03-selfissued-valid-leaf-cert.pem \
+         certs/test/nc-ancestor/03-selfloop-leaf-cert.pem \
+         certs/test/nc-ancestor/03-selfloop-valid-leaf-cert.pem \
          certs/test/nc-ancestor/03-valid-leaf-cert.pem \
          certs/test/nc-ancestor/03-valid-leaf-key.pem

certs/test/nc-ancestor/01-uri-permit-ca-selfissued-cert.pem

@@ -0,0 +1,12 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

certs/test/nc-ancestor/01-uri-permit-ca-selfloop-cert.pem

@@ -0,0 +1,13 @@
+-----BEGIN CERTIFICATE-----
+MIIB7jCCAZSgAwIBAgIBFDAKBggqhkjOPQQDAjA4MQswCQYDVQQGEwJVUzERMA8G
+A1UECgwITkMgVGVzdHMxFjAUBgNVBAMMDVVSSSBQZXJtaXQgQ0EwHhcNMjYxMTA2
+MjA1NzIxWhcNNDYxMTAxMjA1NzIxWjA4MQswCQYDVQQGEwJVUzERMA8GA1UECgwI
+TkMgVGVzdHMxFjAUBgNVBAMMDVVSSSBQZXJtaXQgQ0EwWTATBgcqhkjOPQIBBggq
+hkjOPQMBBwNCAASd89ZOqUGRiGZ6EJPe5Ixql3SJDWwGPoak7hIJUbG1gpq1yPE9
+qRrrjttx/Wdd7F1J2V0Tz06w5U+knZTFg/dvo4GOMIGLMA8GA1UdEwEB/wQFMAMB
+Af8wDgYDVR0PAQH/BAQDAgGGMB0GA1UdDgQWBBQiIiIAIiIiIiIiIiIiIiIiIiIi
+IjBJBgNVHSMEQjBAoTukOTA3MQswCQYDVQQGEwJVUzERMA8GA1UECgwITkMgVGVz
+dHMxFTATBgNVBAMMDE5DIFRlc3QgUm9vdIIBETAKBggqhkjOPQQDAgNIADBFAiEA
+gfxWUW18vk1M0fZz/ATHRqOvgnl6vWzbIfGqIsaXVcoCIHhgbIbWQLRDxzynrd7v
+Ub3/LpirS785DU66GItJ9T39
+-----END CERTIFICATE-----

certs/test/nc-ancestor/01-uri-permit-ca-selfloop-key.pem

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIJiHP3Uaox1ooRULgObGYNCm+lWFtYKA21kCLG7gVJzHoAoGCCqGSM49
+AwEHoUQDQgAEnfPWTqlBkYhmehCT3uSMapd0iQ1sBj6GpO4SCVGxtYKatcjxPaka
+647bcf1nXexdSdldE89OsOVPpJ2UxYP3bw==
+-----END EC PRIVATE KEY-----

certs/test/nc-ancestor/03-selfissued-leaf-cert.pem

@@ -0,0 +1,13 @@
+-----BEGIN CERTIFICATE-----
+MIICBjCCAa2gAwIBAgIBMjAKBggqhkjOPQQDAjA4MQswCQYDVQQGEwJVUzERMA8G
+A1UECgwITkMgVGVzdHMxFjAUBgNVBAMMDVVSSSBQZXJtaXQgQ0EwHhcNMjYxMTA2
+MTkyNzIxWhcNNDYxMTAxMTkyNzIxWjBAMQswCQYDVQQGEwJVUzERMA8GA1UECgwI
+TkMgVGVzdHMxHjAcBgNVBAMMFU5DIFRlc3QgQXR0YWNrZXIgTGVhZjBZMBMGByqG
+SM49AgEGCCqGSM49AwEHA0IABNAzKoFsCE7NysRkRxmHdI61HECHaMhInraZ3s1v
+GrgyYRXvmesAjzZIfCpm58kjRKdJpcKJFL74uaJeM/Gzsl+jgZ8wgZwwDAYDVR0T
+AQH/BAIwADAOBgNVHQ8BAf8EBAMCBaAwEwYDVR0lBAwwCgYIKwYBBQUHAwEwHQYD
+VR0OBBYEFO6GdfO6MvjzgDGAs71HPqOXaCtBMB8GA1UdIwQYMBaAFBERERERERER
+ERERERERERERERERMCcGA1UdEQEB/wQdMBuGGWh0dHBzOi8vYXR0YWNrZXIuY29t
+L2xlYWYwCgYIKoZIzj0EAwIDRwAwRAIgeV2lLWd0ex2wmlUGBL6EKe3qt473LI4P
+q4N9Fb559I0CIB2jHrsRNz+eTJnYGSr1ulYn97ebQD6ZIuDn8lQhvYum
+-----END CERTIFICATE-----

certs/test/nc-ancestor/03-selfissued-valid-leaf-cert.pem

@@ -0,0 +1,13 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

certs/test/nc-ancestor/03-selfloop-leaf-cert.pem

@@ -0,0 +1,13 @@
+-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----

certs/test/nc-ancestor/gen-nc-ancestor.sh

@@ -73,6 +73,29 @@ subjectKeyIdentifier = hash
 authorityKeyIdentifier = keyid
 EOF
 
+cat > "$WORK/selfissued-ca.cnf" <<'EOF'
+[req]
+distinguished_name = dn
+prompt = no
+[dn]
+[v3_selfissued_ca]
+basicConstraints = critical, CA:TRUE
+keyUsage = critical, digitalSignature, keyCertSign, cRLSign
+subjectKeyIdentifier = 11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11:11
+authorityKeyIdentifier = keyid
+EOF
+
+cat > "$WORK/selfloop-ca.cnf" <<'EOF'
+[req]
+distinguished_name = dn
+prompt = no
+[v3_selfloop_ca]
+basicConstraints = critical, CA:TRUE
+keyUsage = critical, digitalSignature, keyCertSign, cRLSign
+subjectKeyIdentifier = 22:22:22:00:22:22:22:22:22:22:22:22:22:22:22:22:22:22:22:22
+authorityKeyIdentifier = issuer:always
+EOF
+
 cat > "$WORK/leaf-attacker.cnf" <<'EOF'
 [req]
 distinguished_name = dn
@@ -149,6 +172,47 @@ mkchild "$DIR/03-valid-leaf-key.pem" "NC Test Valid Leaf" \
     "$DIR/03-valid-leaf-cert.pem" "$WORK/leaf-valid.cnf" \
     v3_leaf_valid 0x31
 
+# ---- 01 uri-permit-ca-selfissued: subject == issuer == uri-permit-ca's DN
+# and uri-permit-ca's key, no NC, distinct SKID. Issued by uri-permit-ca,
+# so it reaches a peer in the chain below it. ----
+
+issuer_cert="$DIR/01-uri-permit-ca-cert.pem"
+issuer_key="$DIR/01-uri-permit-ca-key.pem"
+mkchild "$DIR/01-uri-permit-ca-key.pem" "URI Permit CA" \
+    "$DIR/01-uri-permit-ca-selfissued-cert.pem" "$WORK/selfissued-ca.cnf" \
+    v3_selfissued_ca 0x13
+
+# ---- 03 leaves issued by the self-issued CA ----
+
+issuer_cert="$DIR/01-uri-permit-ca-selfissued-cert.pem"
+issuer_key="$DIR/01-uri-permit-ca-key.pem"
+mkchild "$DIR/03-leaf-attacker-key.pem" "NC Test Attacker Leaf" \
+    "$DIR/03-selfissued-leaf-cert.pem" "$WORK/leaf-attacker.cnf" \
+    v3_leaf_attacker 0x32
+mkchild "$DIR/03-valid-leaf-key.pem" "NC Test Valid Leaf" \
+    "$DIR/03-selfissued-valid-leaf-cert.pem" "$WORK/leaf-valid.cnf" \
+    v3_leaf_valid 0x33
+
+# ---- 01 uri-permit-ca-selfloop: same DN as uri-permit-ca, own key, and an
+# AKID with no keyIdentifier. Its SKID is pinned to uri-permit-ca's CA-table
+# row (first 4 bytes big-endian, modulo 11) so a name lookup reaches it
+# first. ----
+
+issuer_cert="$DIR/01-uri-permit-ca-cert.pem"
+issuer_key="$DIR/01-uri-permit-ca-key.pem"
+mkchild "$DIR/01-uri-permit-ca-selfloop-key.pem" "URI Permit CA" \
+    "$DIR/01-uri-permit-ca-selfloop-cert.pem" "$WORK/selfloop-ca.cnf" \
+    v3_selfloop_ca 0x14
+
+issuer_cert="$DIR/01-uri-permit-ca-selfloop-cert.pem"
+issuer_key="$DIR/01-uri-permit-ca-selfloop-key.pem"
+mkchild "$DIR/03-leaf-attacker-key.pem" "NC Test Attacker Leaf" \
+    "$DIR/03-selfloop-leaf-cert.pem" "$WORK/leaf-attacker.cnf" \
+    v3_leaf_attacker 0x34
+mkchild "$DIR/03-valid-leaf-key.pem" "NC Test Valid Leaf" \
+    "$DIR/03-selfloop-valid-leaf-cert.pem" "$WORK/leaf-valid.cnf" \
+    v3_leaf_valid 0x35
+
 # ---- Concatenated bundle: attacker leaf + benign-sub-ca + uri-permit-ca ----
 
 cat "$WORK/03-leaf-cert.pem" \

linuxkm/linuxkm_wc_port.h

@@ -1171,6 +1171,9 @@
         #ifndef NO_SKID
             struct Signer *GetCAByName(struct WOLFSSL_CERT_MANAGER *cm,
                                        unsigned char *hash);
+            struct Signer *GetCAByNameSkip(struct WOLFSSL_CERT_MANAGER *cm,
+                                           unsigned char *hash,
+                                           const struct Signer *skip);
             #ifdef HAVE_OCSP
                 struct Signer* GetCAByKeyHash(struct WOLFSSL_CERT_MANAGER *cm,
                                               const unsigned char* keyHash);
@@ -1546,6 +1549,7 @@
         typeof(GetCA) *GetCA;
         #ifndef NO_SKID
         typeof(GetCAByName) *GetCAByName;
+        typeof(GetCAByNameSkip) *GetCAByNameSkip;
         #ifdef HAVE_OCSP
         typeof(GetCAByKeyHash) *GetCAByKeyHash;
         #endif /* HAVE_OCSP */
@@ -1842,6 +1846,7 @@
         #define GetCA WC_PIE_INDIRECT_SYM(GetCA)
         #ifndef NO_SKID
             #define GetCAByName WC_PIE_INDIRECT_SYM(GetCAByName)
+            #define GetCAByNameSkip WC_PIE_INDIRECT_SYM(GetCAByNameSkip)
             #ifdef HAVE_OCSP
                 #define GetCAByKeyHash WC_PIE_INDIRECT_SYM(GetCAByKeyHash)
             #endif /* HAVE_OCSP */

linuxkm/module_hooks.c

@@ -2402,6 +2402,7 @@ static int set_up_wolfssl_linuxkm_pie_redirect_table(void) {
     wolfssl_linuxkm_pie_redirect_table.GetCA = GetCA;
 #ifndef NO_SKID
     wolfssl_linuxkm_pie_redirect_table.GetCAByName = GetCAByName;
+    wolfssl_linuxkm_pie_redirect_table.GetCAByNameSkip = GetCAByNameSkip;
 #ifdef HAVE_OCSP
     wolfssl_linuxkm_pie_redirect_table.GetCAByKeyHash = GetCAByKeyHash;
 #endif /* HAVE_OCSP */

src/ssl_certman.c

@@ -3069,6 +3069,13 @@ Signer* GetCAByAKID(WOLFSSL_CERT_MANAGER* cm, const byte* issuer,
 #ifndef NO_SKID
 /* return CA if found, otherwise NULL. Walk through hash table. */
 Signer* GetCAByName(WOLFSSL_CERT_MANAGER* cm, byte* hash)
+{
+    return GetCAByNameSkip(cm, hash, NULL);
+}
+
+/* As GetCAByName() but never returns skip. */
+Signer* GetCAByNameSkip(WOLFSSL_CERT_MANAGER* cm, byte* hash,
+    const Signer* skip)
 {
     Signer* ret = NULL;
     Signer* signers;
@@ -3083,7 +3090,7 @@ Signer* GetCAByName(WOLFSSL_CERT_MANAGER* cm, byte* hash)
     for (row = 0; row < CA_TABLE_SIZE && ret == NULL; row++) {
         signers = cm->caTable[row];
         while (signers && ret == NULL) {
-            if (XMEMCMP(hash, signers->subjectNameHash,
+            if (signers != skip && XMEMCMP(hash, signers->subjectNameHash,
                         SIGNER_DIGEST_SIZE) == 0) {
                 ret = signers;
             }