[libvirt] [PATCH 2/2] Add sanity checking of basic constraints, key purpose & key usage
Daniel P. Berrange
berrange at redhat.com
Tue Jul 19 13:55:09 UTC 2011
Gnutls requires that certificates have basic constraints present
to be used as a CA certificate. OpenSSL doesn't add this data
by default, so add a sanity check to catch this situation. Also
validate that the key usage and key purpose constraints contain
correct data
* src/rpc/virnettlscontext.c: Add sanity checking of certificate
constraints
---
src/rpc/virnettlscontext.c | 132 +++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 130 insertions(+), 2 deletions(-)
diff --git a/src/rpc/virnettlscontext.c b/src/rpc/virnettlscontext.c
index b0dcfe5..d2b1ded 100644
--- a/src/rpc/virnettlscontext.c
+++ b/src/rpc/virnettlscontext.c
@@ -98,6 +98,7 @@ static void virNetTLSLog(int level, const char *str) {
static gnutls_x509_crt_t virNetTLSContextSanityCheckCert(bool isServer,
+ bool isCA,
const char *certFile)
{
gnutls_datum_t data;
@@ -105,6 +106,14 @@ static gnutls_x509_crt_t virNetTLSContextSanityCheckCert(bool isServer,
char *buf = NULL;
int ret = -1;
time_t now;
+ int status;
+ int i;
+ char *buffer = NULL;
+ size_t size;
+ unsigned int usage;
+
+ VIR_DEBUG("isServer %d isCA %d certFile %s",
+ isServer, isCA, certFile);
if ((now = time(NULL)) == ((time_t)-1)) {
virReportSystemError(errno, "%s",
@@ -148,6 +157,124 @@ static gnutls_x509_crt_t virNetTLSContextSanityCheckCert(bool isServer,
goto cleanup;
}
+ status = gnutls_x509_crt_get_basic_constraints(cert, NULL, NULL, NULL);
+ VIR_DEBUG("Cert %s basic constraints %d", certFile, status);
+
+ if (status > 0) { /* It is a CA cert */
+ if (!isCA) {
+ virNetError(VIR_ERR_SYSTEM_ERROR, isServer ?
+ _("The certificate %s basic constraints show a CA, but we need one for a server") :
+ _("The certificate %s basic constraints show a CA, but we need one for a client"),
+ certFile);
+ goto cleanup;
+ }
+ } else if (status == 0) { /* It is not a CA cert */
+ if (isCA) {
+ virNetError(VIR_ERR_SYSTEM_ERROR,
+ _("The certificate %s basic constraints do not show a CA"),
+ certFile);
+ goto cleanup;
+ }
+ } else if (status == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) { /* Missing basicConstraints */
+ if (isCA) {
+ virNetError(VIR_ERR_SYSTEM_ERROR,
+ _("The certificate %s is missing basic constraints for a CA"),
+ certFile);
+ goto cleanup;
+ }
+ } else { /* General error */
+ virNetError(VIR_ERR_SYSTEM_ERROR,
+ _("Unable to query certificate %s basic constraints %s"),
+ certFile, gnutls_strerror(status));
+ goto cleanup;
+ }
+
+ status = gnutls_x509_crt_get_key_usage(cert, &usage, NULL);
+
+ VIR_DEBUG("Cert %s key usage status %d usage %d", certFile, status, usage);
+ if (status < 0) {
+ virNetError(VIR_ERR_SYSTEM_ERROR,
+ _("Unable to query certificate %s basic constraints %s"),
+ certFile, gnutls_strerror(status));
+ goto cleanup;
+ }
+
+ if (usage & GNUTLS_KEY_KEY_CERT_SIGN) {
+ if (!isCA) {
+ virNetError(VIR_ERR_SYSTEM_ERROR, isServer ?
+ _("Certificate server usage is for certificate signing, but wanted a %s certificate") :
+ _("Certificate client usage is for certificate signing, but wanted a %s certificate"),
+ certFile);
+ goto cleanup;
+ }
+ } else {
+ if (isCA) {
+ virNetError(VIR_ERR_SYSTEM_ERROR,
+ _("Certificate %s usage is for not certificate signing"),
+ certFile);
+ goto cleanup;
+ }
+ }
+
+ for (i = 0 ; ; i++) {
+ size = 0;
+ status = gnutls_x509_crt_get_key_purpose_oid(cert, i, buffer, &size, NULL);
+
+ if (status == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {
+ VIR_DEBUG("No key purpose data available, skipping checks");
+ break;
+ }
+ if (status != GNUTLS_E_SHORT_MEMORY_BUFFER) {
+ virNetError(VIR_ERR_SYSTEM_ERROR,
+ _("Unable to query certificate %s key purpose %s"),
+ certFile, gnutls_strerror(status));
+ goto cleanup;
+ }
+
+ if (VIR_ALLOC_N(buffer, size) < 0) {
+ virReportOOMError();
+ goto cleanup;
+ }
+
+ status = gnutls_x509_crt_get_key_purpose_oid(cert, i, buffer, &size, NULL);
+ if (status < 0) {
+ virNetError(VIR_ERR_SYSTEM_ERROR,
+ _("Unable to query certificate %s key purpose %s"),
+ certFile, gnutls_strerror(status));
+ goto cleanup;
+ }
+
+ VIR_DEBUG("Key purpose %d %s", status, buffer);
+ if (STREQ(buffer, GNUTLS_KP_TLS_WWW_SERVER)) {
+ if (isCA || !isServer) {
+ virNetError(VIR_ERR_SYSTEM_ERROR, isCA ?
+ _("Certificate CA purpose is TLS server, but wanted a %s certificate") :
+ _("Certificate TLS client purpose is TLS server, but wanted a %s certificate"),
+ certFile);
+ goto cleanup;
+ }
+ } else if (STREQ(buffer, GNUTLS_KP_TLS_WWW_CLIENT)) {
+ if (isCA || isServer) {
+ virNetError(VIR_ERR_SYSTEM_ERROR, isCA ?
+ _("Certificate CA purpose is TLS client, but wanted a %s certificate") :
+ _("Certificate TLS server purpose is TLS client, but wanted a %s certificate"),
+ certFile);
+ goto cleanup;
+ }
+ } else if (STRNEQ(buffer, GNUTLS_KP_ANY)) {
+ virNetError(VIR_ERR_SYSTEM_ERROR, (isCA ?
+ _("Certificate CA purpose is wrong, wanted a %s certificate") :
+ (isServer ?
+ _("Certificate TLS server purpose is wrong, wanted a %s certificate") :
+ _("Certificate TLS client purpose is wrong, wanted a %s certificate"))),
+ certFile);
+ goto cleanup;
+ }
+
+ VIR_FREE(buffer);
+ }
+
+
ret = 0;
cleanup:
@@ -155,6 +282,7 @@ cleanup:
gnutls_x509_crt_deinit(cert);
cert = NULL;
}
+ VIR_FREE(buffer);
VIR_FREE(buf);
return cert;
}
@@ -170,11 +298,11 @@ static int virNetTLSContextSanityCheckCredentials(bool isServer,
unsigned int status;
if (access(certFile, R_OK) == 0) {
- if (!(cert = virNetTLSContextSanityCheckCert(isServer, certFile)))
+ if (!(cert = virNetTLSContextSanityCheckCert(isServer, false, certFile)))
goto cleanup;
}
if (access(cacertFile, R_OK) == 0) {
- if (!(cacert = virNetTLSContextSanityCheckCert(isServer, cacertFile)))
+ if (!(cacert = virNetTLSContextSanityCheckCert(isServer, true, cacertFile)))
goto cleanup;
}
--
1.7.4.4
More information about the libvir-list
mailing list