Fix validation of CA certificate chains

The code added to validate CA certificates did not take into
account the possibility that the cacert.pem file can contain
multiple (concatenated) cert data blocks. Extend the code for
loading CA certs to use the gnutls APIs for loading cert lists.
Add test cases to check that multi-level trees of certs will
validate correctly.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

diff --git a/src/rpc/virnettlscontext.c b/src/rpc/virnettlscontext.c
index af0ec2145479ea9bc9b108c94622a4efce594377..2beee8ff385cf994d01969f088dd56a27627c38b 100644 (file)
--- a/src/rpc/virnettlscontext.c
+++ b/src/rpc/virnettlscontext.c
@@ -455,14 +455,15 @@ static int virNetTLSContextCheckCert(gnutls_x509_crt_t cert,
 
 static int virNetTLSContextCheckCertPair(gnutls_x509_crt_t cert,
                                          const char *certFile,
-                                         gnutls_x509_crt_t cacert,
+                                         gnutls_x509_crt_t *cacerts,
+                                         size_t ncacerts,
                                          const char *cacertFile,
                                          bool isServer)
 {
     unsigned int status;
 
     if (gnutls_x509_crt_list_verify(&cert, 1,
-                                    &cacert, 1,
+                                    cacerts, ncacerts,
                                     NULL, 0,
                                     0, &status) < 0) {
         virReportError(VIR_ERR_SYSTEM_ERROR, isServer ?
@@ -500,16 +501,15 @@ static int virNetTLSContextCheckCertPair(gnutls_x509_crt_t cert,
 
 
 static gnutls_x509_crt_t virNetTLSContextLoadCertFromFile(const char *certFile,
-                                                          bool isServer,
-                                                          bool isCA ATTRIBUTE_UNUSED)
+                                                          bool isServer)
 {
     gnutls_datum_t data;
     gnutls_x509_crt_t cert = NULL;
     char *buf = NULL;
     int ret = -1;
 
-    VIR_DEBUG("isServer %d isCA %d certFile %s",
-              isServer, isCA, certFile);
+    VIR_DEBUG("isServer %d certFile %s",
+              isServer, certFile);
 
     if (gnutls_x509_crt_init(&cert) < 0) {
         virReportError(VIR_ERR_SYSTEM_ERROR, "%s",
@@ -543,31 +543,69 @@ cleanup:
 }
 
 
+static int virNetTLSContextLoadCACertListFromFile(const char *certFile,
+                                                  gnutls_x509_crt_t *certs,
+                                                  size_t *ncerts)
+{
+    gnutls_datum_t data;
+    char *buf = NULL;
+    int ret = -1;
+    unsigned int certMax = *ncerts;
+
+    *ncerts = 0;
+    VIR_DEBUG("certFile %s", certFile);
+
+    if (virFileReadAll(certFile, (1<<16), &buf) < 0)
+        goto cleanup;
+
+    data.data = (unsigned char *)buf;
+    data.size = strlen(buf);
+
+    if (gnutls_x509_crt_list_import(certs, &certMax, &data, GNUTLS_X509_FMT_PEM, 0) < 0) {
+        virReportError(VIR_ERR_SYSTEM_ERROR,
+                       _("Unable to import CA certificate list %s"),
+                       certFile);
+        goto cleanup;
+    }
+    *ncerts = certMax;
+
+    ret = 0;
+
+cleanup:
+    VIR_FREE(buf);
+    return ret;
+}
+
+
+#define MAX_CERTS 16
 static int virNetTLSContextSanityCheckCredentials(bool isServer,
                                                   const char *cacertFile,
                                                   const char *certFile)
 {
     gnutls_x509_crt_t cert = NULL;
-    gnutls_x509_crt_t cacert = NULL;
+    gnutls_x509_crt_t cacerts[MAX_CERTS];
+    size_t ncacerts = MAX_CERTS;
+    size_t i;
     int ret = -1;
 
     if ((access(certFile, R_OK) == 0) &&
-        !(cert = virNetTLSContextLoadCertFromFile(certFile, isServer, false)))
+        !(cert = virNetTLSContextLoadCertFromFile(certFile, isServer)))
         goto cleanup;
     if ((access(cacertFile, R_OK) == 0) &&
-        !(cacert = virNetTLSContextLoadCertFromFile(cacertFile, isServer, false)))
+        virNetTLSContextLoadCACertListFromFile(cacertFile, cacerts, &ncacerts) < 0)
         goto cleanup;
 
     if (cert &&
         virNetTLSContextCheckCert(cert, certFile, isServer, false) < 0)
         goto cleanup;
 
-    if (cacert &&
-        virNetTLSContextCheckCert(cacert, cacertFile, isServer, true) < 0)
-        goto cleanup;
+    for (i = 0; i < ncacerts; i++) {
+        if (virNetTLSContextCheckCert(cacerts[i], cacertFile, isServer, true) < 0)
+            goto cleanup;
+    }
 
-    if (cert && cacert &&
-        virNetTLSContextCheckCertPair(cert, certFile, cacert, cacertFile, isServer) < 0)
+    if (cert && ncacerts &&
+        virNetTLSContextCheckCertPair(cert, certFile, cacerts, ncacerts, cacertFile, isServer) < 0)
         goto cleanup;
 
     ret = 0;
@@ -575,8 +613,8 @@ static int virNetTLSContextSanityCheckCredentials(bool isServer,
 cleanup:
     if (cert)
         gnutls_x509_crt_deinit(cert);
-    if (cacert)
-        gnutls_x509_crt_deinit(cacert);
+    for (i = 0; i < ncacerts; i++)
+        gnutls_x509_crt_deinit(cacerts[i]);
     return ret;
 }
 

diff --git a/tests/virnettlscontexttest.c b/tests/virnettlscontexttest.c
index 3012c4a4f2dbee6c544e5f38d1f00409093a799e..9ade7858cafe22c4b7409b2ba4ffc8117e58497d 100644 (file)
--- a/tests/virnettlscontexttest.c
+++ b/tests/virnettlscontexttest.c
@@ -510,6 +510,57 @@ mymain(void)
     DO_CTX_TEST(true, cacertreq.filename, servercertnew1req.filename, true);
     DO_CTX_TEST(false, cacertreq.filename, clientcertnew1req.filename, true);
 
+    TLS_ROOT_REQ(cacertrootreq,
+                 "UK", "libvirt root", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(cacertlevel1areq, cacertrootreq,
+                 "UK", "libvirt level 1a", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(cacertlevel1breq, cacertrootreq,
+                 "UK", "libvirt level 1b", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(cacertlevel2areq, cacertlevel1areq,
+                 "UK", "libvirt level 2a", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(servercertlevel3areq, cacertlevel2areq,
+                 "UK", "libvirt.org", NULL, NULL, NULL, NULL,
+                 true, true, false,
+                 true, true, GNUTLS_KEY_DIGITAL_SIGNATURE | GNUTLS_KEY_KEY_ENCIPHERMENT,
+                 true, true, GNUTLS_KP_TLS_WWW_SERVER, NULL,
+                 0, 0);
+    TLS_CERT_REQ(clientcertlevel2breq, cacertlevel1breq,
+                 "UK", "libvirt client level 2b", NULL, NULL, NULL, NULL,
+                 true, true, false,
+                 true, true, GNUTLS_KEY_DIGITAL_SIGNATURE | GNUTLS_KEY_KEY_ENCIPHERMENT,
+                 true, true, GNUTLS_KP_TLS_WWW_CLIENT, NULL,
+                 0, 0);
+
+    gnutls_x509_crt_t certchain[] = {
+        cacertrootreq.crt,
+        cacertlevel1areq.crt,
+        cacertlevel1breq.crt,
+        cacertlevel2areq.crt,
+    };
+
+    testTLSWriteCertChain("cacertchain.pem",
+                          certchain,
+                          ARRAY_CARDINALITY(certchain));
+
+    DO_CTX_TEST(true, "cacertchain.pem", servercertlevel3areq.filename, false);
+    DO_CTX_TEST(false, "cacertchain.pem", clientcertlevel2breq.filename, false);
+
     testTLSDiscardCert(&cacertreq);
     testTLSDiscardCert(&cacert1req);
     testTLSDiscardCert(&cacert2req);
@@ -558,6 +609,14 @@ mymain(void)
     testTLSDiscardCert(&servercertnew1req);
     testTLSDiscardCert(&clientcertnew1req);
 
+    testTLSDiscardCert(&cacertrootreq);
+    testTLSDiscardCert(&cacertlevel1areq);
+    testTLSDiscardCert(&cacertlevel1breq);
+    testTLSDiscardCert(&cacertlevel2areq);
+    testTLSDiscardCert(&servercertlevel3areq);
+    testTLSDiscardCert(&clientcertlevel2breq);
+    unlink("cacertchain.pem");
+
     testTLSCleanup();
 
     return ret==0 ? EXIT_SUCCESS : EXIT_FAILURE;

diff --git a/tests/virnettlshelpers.c b/tests/virnettlshelpers.c
index 8236e8203c3ef4335fbca8ce3ad9b04a8061ccb8..39a2df65ab7f5bc54363affaf07b571b2e7952d9 100644 (file)
--- a/tests/virnettlshelpers.c
+++ b/tests/virnettlshelpers.c
@@ -406,6 +406,40 @@ testTLSGenerateCert(struct testTLSCertReq *req,
 }
 
 
+void testTLSWriteCertChain(const char *filename,
+                           gnutls_x509_crt_t *certs,
+                           size_t ncerts)
+{
+    size_t i;
+    int fd;
+    int err;
+    static char buffer[1024*1024];
+    size_t size;
+
+    if ((fd = open(filename, O_WRONLY|O_CREAT, 0600)) < 0) {
+        VIR_WARN("Failed to open %s", filename);
+        abort();
+    }
+
+    for (i = 0; i < ncerts; i++) {
+        size = sizeof(buffer);
+        if ((err = gnutls_x509_crt_export(certs[i], GNUTLS_X509_FMT_PEM, buffer, &size) < 0)) {
+            VIR_WARN("Failed to export certificate %s", gnutls_strerror(err));
+            unlink(filename);
+            abort();
+        }
+
+        if (safewrite(fd, buffer, size) != size) {
+            VIR_WARN("Failed to write certificate to %s", filename);
+            unlink(filename);
+            abort();
+        }
+    }
+
+    VIR_FORCE_CLOSE(fd);
+}
+
+
 void testTLSDiscardCert(struct testTLSCertReq *req)
 {
     if (!req->crt)

diff --git a/tests/virnettlshelpers.h b/tests/virnettlshelpers.h
index 50a4ba1b537c6c3dca346d18968b4b88f6b2bdb1..7c3f8da944af1db2451f9148e7a14a2b84aed532 100644 (file)
--- a/tests/virnettlshelpers.h
+++ b/tests/virnettlshelpers.h
@@ -71,6 +71,9 @@ struct testTLSCertReq {
 
 void testTLSGenerateCert(struct testTLSCertReq *req,
                          gnutls_x509_crt_t ca);
+void testTLSWriteCertChain(const char *filename,
+                           gnutls_x509_crt_t *certs,
+                           size_t ncerts);
 void testTLSDiscardCert(struct testTLSCertReq *req);
 
 void testTLSInit(void);

diff --git a/tests/virnettlssessiontest.c b/tests/virnettlssessiontest.c
index 8636fc8e81281b697236e95d6b519594b02e3566..bc176aaad410c3467214009f473a7e87f1689f0d 100644 (file)
--- a/tests/virnettlssessiontest.c
+++ b/tests/virnettlssessiontest.c
@@ -193,7 +193,7 @@ static int testTLSSessionInit(const void *opaque)
             VIR_WARN("Expected server cert check fail");
             goto cleanup;
         } else {
-            VIR_DEBUG("Not unexpected server cert fail");
+            VIR_DEBUG("No unexpected server cert fail");
         }
     }
 
@@ -213,7 +213,7 @@ static int testTLSSessionInit(const void *opaque)
             VIR_WARN("Expected client cert check fail");
             goto cleanup;
         } else {
-            VIR_DEBUG("Not unexpected client cert fail");
+            VIR_DEBUG("No unexpected client cert fail");
         }
     }
 
@@ -405,6 +405,57 @@ mymain(void)
     DO_SESS_TEST(cacertreq.filename, servercertreq.filename, clientcertreq.filename,
                  false, false, "libvirt.org", wildcards6);
 
+    TLS_ROOT_REQ(cacertrootreq,
+                 "UK", "libvirt root", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(cacertlevel1areq, cacertrootreq,
+                 "UK", "libvirt level 1a", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(cacertlevel1breq, cacertrootreq,
+                 "UK", "libvirt level 1b", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(cacertlevel2areq, cacertlevel1areq,
+                 "UK", "libvirt level 2a", NULL, NULL, NULL, NULL,
+                 true, true, true,
+                 true, true, GNUTLS_KEY_KEY_CERT_SIGN,
+                 false, false, NULL, NULL,
+                 0, 0);
+    TLS_CERT_REQ(servercertlevel3areq, cacertlevel2areq,
+                 "UK", "libvirt.org", NULL, NULL, NULL, NULL,
+                 true, true, false,
+                 true, true, GNUTLS_KEY_DIGITAL_SIGNATURE | GNUTLS_KEY_KEY_ENCIPHERMENT,
+                 true, true, GNUTLS_KP_TLS_WWW_SERVER, NULL,
+                 0, 0);
+    TLS_CERT_REQ(clientcertlevel2breq, cacertlevel1breq,
+                 "UK", "libvirt client level 2b", NULL, NULL, NULL, NULL,
+                 true, true, false,
+                 true, true, GNUTLS_KEY_DIGITAL_SIGNATURE | GNUTLS_KEY_KEY_ENCIPHERMENT,
+                 true, true, GNUTLS_KP_TLS_WWW_CLIENT, NULL,
+                 0, 0);
+
+    gnutls_x509_crt_t certchain[] = {
+        cacertrootreq.crt,
+        cacertlevel1areq.crt,
+        cacertlevel1breq.crt,
+        cacertlevel2areq.crt,
+    };
+
+    testTLSWriteCertChain("cacertchain.pem",
+                          certchain,
+                          ARRAY_CARDINALITY(certchain));
+
+    DO_SESS_TEST("cacertchain.pem", servercertlevel3areq.filename, clientcertlevel2breq.filename,
+                 false, false, "libvirt.org", NULL);
+
     testTLSDiscardCert(&clientcertreq);
     testTLSDiscardCert(&clientcertaltreq);
 
@@ -415,6 +466,14 @@ mymain(void)
     testTLSDiscardCert(&cacertreq);
     testTLSDiscardCert(&altcacertreq);
 
+    testTLSDiscardCert(&cacertrootreq);
+    testTLSDiscardCert(&cacertlevel1areq);
+    testTLSDiscardCert(&cacertlevel1breq);
+    testTLSDiscardCert(&cacertlevel2areq);
+    testTLSDiscardCert(&servercertlevel3areq);
+    testTLSDiscardCert(&clientcertlevel2breq);
+    unlink("cacertchain.pem");
+
     testTLSCleanup();
 
     return ret==0 ? EXIT_SUCCESS : EXIT_FAILURE;