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[libvirt] [PATCH 1/3] Refactor some daemon code to facilitate introduction of static probes



Refactor some daemon code to facilitate the introductioin of static
probes, sanitizing function exit paths in many places

* daemon/libvirtd.c: Pass the dname string into remoteCheckDN
  to let caller deal with failure paths. Add separate exit paths
  to remoteCheckCertificate for auth failure vs denial. Merge
  all exit paths in qemudDispatchServer to one cleanup block
* daemon/remote.c: Add separate exit paths to SASL & PolicyKit
  functions for auth failure vs denial
---
 daemon/libvirtd.c |  160 +++++++++++++++++++++++++++--------------------------
 daemon/remote.c   |   83 ++++++++++++++++++++++------
 2 files changed, 147 insertions(+), 96 deletions(-)

diff --git a/daemon/libvirtd.c b/daemon/libvirtd.c
index 711360b..5e18077 100644
--- a/daemon/libvirtd.c
+++ b/daemon/libvirtd.c
@@ -1116,19 +1116,9 @@ remoteInitializeTLSSession (void)
 
 /* Check DN is on tls_allowed_dn_list. */
 static int
-remoteCheckDN (gnutls_x509_crt_t cert)
+remoteCheckDN (const char *dname)
 {
-    char name[256];
-    size_t namesize = sizeof name;
     char **wildcards;
-    int err;
-
-    err = gnutls_x509_crt_get_dn (cert, name, &namesize);
-    if (err != 0) {
-        VIR_ERROR(_("remoteCheckDN: gnutls_x509_cert_get_dn: %s"),
-                  gnutls_strerror (err));
-        return 0;
-    }
 
     /* If the list is not set, allow any DN. */
     wildcards = tls_allowed_dn_list;
@@ -1136,62 +1126,62 @@ remoteCheckDN (gnutls_x509_crt_t cert)
         return 1;
 
     while (*wildcards) {
-        if (fnmatch (*wildcards, name, 0) == 0)
+        if (fnmatch (*wildcards, dname, 0) == 0)
             return 1;
         wildcards++;
     }
 
     /* Print the client's DN. */
-    DEBUG(_("remoteCheckDN: failed: client DN is %s"), name);
+    DEBUG(_("remoteCheckDN: failed: client DN is %s"), dname);
 
     return 0; // Not found.
 }
 
 static int
-remoteCheckCertificate (gnutls_session_t session)
+remoteCheckCertificate(struct qemud_client *client)
 {
     int ret;
     unsigned int status;
     const gnutls_datum_t *certs;
     unsigned int nCerts, i;
     time_t now;
+    char name[256];
+    size_t namesize = sizeof name;
+
+    memset(name, 0, namesize);
 
-    if ((ret = gnutls_certificate_verify_peers2 (session, &status)) < 0){
-        VIR_ERROR(_("remoteCheckCertificate: verify failed: %s"),
+    if ((ret = gnutls_certificate_verify_peers2 (client->tlssession, &status)) < 0){
+        VIR_ERROR(_("Failed to verify certificate peers: %s"),
                   gnutls_strerror (ret));
-        return -1;
+        goto authdeny;
     }
 
     if (status != 0) {
         if (status & GNUTLS_CERT_INVALID)
-            VIR_ERROR0(_("remoteCheckCertificate: "
-                         "the client certificate is not trusted."));
+            VIR_ERROR0(_("The client certificate is not trusted."));
 
         if (status & GNUTLS_CERT_SIGNER_NOT_FOUND)
-            VIR_ERROR0(_("remoteCheckCertificate: the client "
-                         "certificate has unknown issuer."));
+            VIR_ERROR0(_("The client certificate has unknown issuer."));
 
         if (status & GNUTLS_CERT_REVOKED)
-            VIR_ERROR0(_("remoteCheckCertificate: "
-                         "the client certificate has been revoked."));
+            VIR_ERROR0(_("The client certificate has been revoked."));
 
 #ifndef GNUTLS_1_0_COMPAT
         if (status & GNUTLS_CERT_INSECURE_ALGORITHM)
-            VIR_ERROR0(_("remoteCheckCertificate: the client certificate"
-                         " uses an insecure algorithm."));
+            VIR_ERROR0(_("The client certificate uses an insecure algorithm."));
 #endif
 
-        return -1;
+        goto authdeny;
     }
 
-    if (gnutls_certificate_type_get (session) != GNUTLS_CRT_X509) {
-        VIR_ERROR0(_("remoteCheckCertificate: certificate is not X.509"));
-        return -1;
+    if (gnutls_certificate_type_get(client->tlssession) != GNUTLS_CRT_X509) {
+        VIR_ERROR0(_("Only x509 certificates are supported"));
+        goto authdeny;
     }
 
-    if (!(certs = gnutls_certificate_get_peers(session, &nCerts))) {
-        VIR_ERROR0(_("remoteCheckCertificate: no peers"));
-        return -1;
+    if (!(certs = gnutls_certificate_get_peers(client->tlssession, &nCerts))) {
+        VIR_ERROR0(_("The certificate has no peers"));
+        goto authdeny;
     }
 
     now = time (NULL);
@@ -1200,40 +1190,57 @@ remoteCheckCertificate (gnutls_session_t session)
         gnutls_x509_crt_t cert;
 
         if (gnutls_x509_crt_init (&cert) < 0) {
-            VIR_ERROR0(_("remoteCheckCertificate: gnutls_x509_crt_init failed"));
-            return -1;
+            VIR_ERROR0(_("Unable to initialize certificate"));
+            goto authfail;
         }
 
         if (gnutls_x509_crt_import(cert, &certs[i], GNUTLS_X509_FMT_DER) < 0) {
+            VIR_ERROR0(_("Unable to load certificate"));
             gnutls_x509_crt_deinit (cert);
-            return -1;
+            goto authfail;
+        }
+
+        if (i == 0) {
+            ret = gnutls_x509_crt_get_dn (cert, name, &namesize);
+            if (ret != 0) {
+                VIR_ERROR(_("Failed to get certificate distinguished name: %s"),
+                          gnutls_strerror(ret));
+                gnutls_x509_crt_deinit (cert);
+                goto authfail;
+            }
+
+            if (!remoteCheckDN (name)) {
+                /* This is the most common error: make it informative. */
+                VIR_ERROR0(_("Client's Distinguished Name is not on the list "
+                             "of allowed clients (tls_allowed_dn_list).  Use "
+                             "'certtool -i -infile clientcert.pem' to view the"
+                             "Distinguished Name field in the client certificate,"
+                             "or run this daemon with --verbose option."));
+                gnutls_x509_crt_deinit (cert);
+                goto authdeny;
+            }
         }
 
         if (gnutls_x509_crt_get_expiration_time (cert) < now) {
-            VIR_ERROR0(_("remoteCheckCertificate: "
-                         "the client certificate has expired"));
+            VIR_ERROR0(_("The client certificate has expired"));
             gnutls_x509_crt_deinit (cert);
-            return -1;
+            goto authdeny;
         }
 
         if (gnutls_x509_crt_get_activation_time (cert) > now) {
-            VIR_ERROR0(_("remoteCheckCertificate: the client "
-                         "certificate is not yet activated"));
+            VIR_ERROR0(_("The client certificate is not yet active"));
             gnutls_x509_crt_deinit (cert);
-            return -1;
-        }
-
-        if (i == 0) {
-            if (!remoteCheckDN (cert)) {
-                /* This is the most common error: make it informative. */
-                VIR_ERROR0(_("remoteCheckCertificate: client's Distinguished Name is not on the list of allowed clients (tls_allowed_dn_list).  Use 'openssl x509 -in clientcert.pem -text' to view the Distinguished Name field in the client certificate, or run this daemon with --verbose option."));
-                gnutls_x509_crt_deinit (cert);
-                return -1;
-            }
+            goto authdeny;
         }
     }
 
     return 0;
+
+authdeny:
+    return -1;
+
+authfail:
+    return -1;
 }
 
 /* Check the client's access. */
@@ -1243,7 +1250,7 @@ remoteCheckAccess (struct qemud_client *client)
     struct qemud_client_message *confirm;
 
     /* Verify client certificate. */
-    if (remoteCheckCertificate (client->tlssession) == -1) {
+    if (remoteCheckCertificate (client) == -1) {
         VIR_ERROR0(_("remoteCheckCertificate: "
                      "failed to verify client's certificate"));
         if (!tls_no_verify_certificate) return -1;
@@ -1301,7 +1308,7 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
     int fd;
     struct sockaddr_storage addr;
     socklen_t addrlen = (socklen_t) (sizeof addr);
-    struct qemud_client *client;
+    struct qemud_client *client = NULL;
     int no_slow_start = 1;
     int i;
 
@@ -1316,14 +1323,12 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
 
     if (server->nclients >= max_clients) {
         VIR_ERROR(_("Too many active clients (%d), dropping connection"), max_clients);
-        close(fd);
-        return -1;
+        goto error;
     }
 
     if (VIR_REALLOC_N(server->clients, server->nclients+1) < 0) {
         VIR_ERROR0(_("Out of memory allocating clients"));
-        close(fd);
-        return -1;
+        goto error;
     }
 
 #ifdef __sun
@@ -1335,14 +1340,12 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
             (privs = ucred_getprivset (ucred, PRIV_EFFECTIVE)) == NULL) {
             if (ucred != NULL)
                 ucred_free (ucred);
-            close (fd);
-            return -1;
+            goto error;
         }
 
         if (!priv_ismember (privs, PRIV_VIRT_MANAGE)) {
             ucred_free (ucred);
-            close (fd);
-            return -1;
+            goto error;
         }
 
         ucred_free (ucred);
@@ -1355,16 +1358,14 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
 
     if (virSetCloseExec(fd) < 0 ||
         virSetNonBlock(fd) < 0) {
-        close(fd);
-        return -1;
+        goto error;
     }
 
     if (VIR_ALLOC(client) < 0)
-        goto cleanup;
+        goto error;
     if (virMutexInit(&client->lock) < 0) {
         VIR_ERROR0(_("cannot initialize mutex"));
-        VIR_FREE(client);
-        goto cleanup;
+        goto error;
     }
 
     client->magic = QEMUD_CLIENT_MAGIC;
@@ -1381,7 +1382,7 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
 
     /* Prepare one for packet receive */
     if (VIR_ALLOC(client->rx) < 0)
-        goto cleanup;
+        goto error;
     client->rx->bufferLength = REMOTE_MESSAGE_HEADER_XDR_LEN;
 
 
@@ -1395,7 +1396,7 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
         pid_t pid;
 
         if (qemudGetSocketIdentity(client->fd, &uid, &pid) < 0)
-            goto cleanup;
+            goto error;
 
         /* Client is running as root, so disable auth */
         if (uid == 0) {
@@ -1408,13 +1409,13 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
     if (client->type != QEMUD_SOCK_TYPE_TLS) {
         /* Plain socket, so prepare to read first message */
         if (qemudRegisterClientEvent (server, client) < 0)
-            goto cleanup;
+            goto error;
     } else {
         int ret;
 
         client->tlssession = remoteInitializeTLSSession ();
         if (client->tlssession == NULL)
-            goto cleanup;
+            goto error;
 
         gnutls_transport_set_ptr (client->tlssession,
                                   (gnutls_transport_ptr_t) (long) fd);
@@ -1426,21 +1427,21 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
 
             /* Unlikely, but ...  Next step is to check the certificate. */
             if (remoteCheckAccess (client) == -1)
-                goto cleanup;
+                goto error;
 
             /* Handshake & cert check OK,  so prepare to read first message */
             if (qemudRegisterClientEvent(server, client) < 0)
-                goto cleanup;
+                goto error;
         } else if (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN) {
             /* Most likely, need to do more handshake data */
             client->handshake = 1;
 
             if (qemudRegisterClientEvent (server, client) < 0)
-                goto cleanup;
+                goto error;
         } else {
             VIR_ERROR(_("TLS handshake failed: %s"),
                       gnutls_strerror (ret));
-            goto cleanup;
+            goto error;
         }
     }
 
@@ -1461,13 +1462,14 @@ static int qemudDispatchServer(struct qemud_server *server, struct qemud_socket
 
     return 0;
 
- cleanup:
-    if (client &&
-        client->tlssession) gnutls_deinit (client->tlssession);
+error:
+    if (client) {
+        if (client->tlssession) gnutls_deinit (client->tlssession);
+        if (client)
+            VIR_FREE(client->rx);
+        VIR_FREE(client);
+    }
     close (fd);
-    if (client)
-        VIR_FREE(client->rx);
-    VIR_FREE(client);
     return -1;
 }
 
diff --git a/daemon/remote.c b/daemon/remote.c
index 118654c..3db9790 100644
--- a/daemon/remote.c
+++ b/daemon/remote.c
@@ -3460,7 +3460,9 @@ error:
 
 
 /* We asked for an SSF layer, so sanity check that we actually
- * got what we asked for */
+ * got what we asked for
+ * Returns 0 if ok, -1 on error, -2 if rejected
+ */
 static int
 remoteSASLCheckSSF (struct qemud_client *client,
                     remote_error *rerr) {
@@ -3487,7 +3489,7 @@ remoteSASLCheckSSF (struct qemud_client *client,
         remoteDispatchAuthError(rerr);
         sasl_dispose(&client->saslconn);
         client->saslconn = NULL;
-        return -1;
+        return -2;
     }
 
     /* Only setup for read initially, because we're about to send an RPC
@@ -3502,6 +3504,9 @@ remoteSASLCheckSSF (struct qemud_client *client,
     return 0;
 }
 
+/*
+ * Returns 0 if ok, -1 on error, -2 if rejected
+ */
 static int
 remoteSASLCheckAccess (struct qemud_server *server,
                        struct qemud_client *client,
@@ -3553,7 +3558,7 @@ remoteSASLCheckAccess (struct qemud_server *server,
     remoteDispatchAuthError(rerr);
     sasl_dispose(&client->saslconn);
     client->saslconn = NULL;
-    return -1;
+    return -2;
 }
 
 
@@ -3625,12 +3630,14 @@ remoteDispatchAuthSaslStart (struct qemud_server *server,
     if (err == SASL_CONTINUE) {
         ret->complete = 0;
     } else {
-        if (remoteSASLCheckSSF(client, rerr) < 0)
-            goto error;
-
         /* Check username whitelist ACL */
-        if (remoteSASLCheckAccess(server, client, rerr) < 0)
-            goto error;
+        if ((err = remoteSASLCheckAccess(server, client, rerr)) < 0 ||
+            (err = remoteSASLCheckSSF(client, rerr)) < 0) {
+            if (err == -2)
+                goto authdeny;
+            else
+                goto authfail;
+        }
 
         REMOTE_DEBUG("Authentication successful %d", client->fd);
         ret->complete = 1;
@@ -3642,6 +3649,11 @@ remoteDispatchAuthSaslStart (struct qemud_server *server,
 
 authfail:
     remoteDispatchAuthError(rerr);
+    goto error;
+
+authdeny:
+    goto error;
+
 error:
     virMutexUnlock(&client->lock);
     return -1;
@@ -3714,12 +3726,14 @@ remoteDispatchAuthSaslStep (struct qemud_server *server,
     if (err == SASL_CONTINUE) {
         ret->complete = 0;
     } else {
-        if (remoteSASLCheckSSF(client, rerr) < 0)
-            goto error;
-
         /* Check username whitelist ACL */
-        if (remoteSASLCheckAccess(server, client, rerr) < 0)
-            goto error;
+        if ((err = remoteSASLCheckAccess(server, client, rerr)) < 0 ||
+            (err = remoteSASLCheckSSF(client, rerr)) < 0) {
+            if (err == -2)
+                goto authdeny;
+            else
+                goto authfail;
+        }
 
         REMOTE_DEBUG("Authentication successful %d", client->fd);
         ret->complete = 1;
@@ -3731,6 +3745,11 @@ remoteDispatchAuthSaslStep (struct qemud_server *server,
 
 authfail:
     remoteDispatchAuthError(rerr);
+    goto error;
+
+authdeny:
+    goto error;
+
 error:
     virMutexUnlock(&client->lock);
     return -1;
@@ -3792,13 +3811,16 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
                           void *args ATTRIBUTE_UNUSED,
                           remote_auth_polkit_ret *ret)
 {
-    pid_t callerPid;
-    uid_t callerUid;
+    pid_t callerPid = -1;
+    uid_t callerUid = -1;
     const char *action;
     int status = -1;
     char pidbuf[50];
+    char ident[100];
     int rv;
 
+    memset(ident, 0, sizeof ident);
+
     virMutexLock(&server->lock);
     virMutexLock(&client->lock);
     virMutexUnlock(&server->lock);
@@ -3834,6 +3856,12 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
         goto authfail;
     }
 
+    rv = snprintf(ident, sizeof ident, "pid:%d,uid:%d", callerPid, callerUid);
+    if (rv < 0 || rv >= sizeof ident) {
+        VIR_ERROR(_("Caller identity was too large %d:%d"), callerPid, callerUid);
+        goto authfail;
+    }
+
     if (virRun(pkcheck, &status) < 0) {
         VIR_ERROR(_("Cannot invoke %s"), PKCHECK_PATH);
         goto authfail;
@@ -3841,7 +3869,7 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
     if (status != 0) {
         VIR_ERROR(_("Policy kit denied action %s from pid %d, uid %d, result: %d"),
                   action, callerPid, callerUid, status);
-        goto authfail;
+        goto authdeny;
     }
     VIR_INFO(_("Policy allowed action %s from pid %d, uid %d"),
              action, callerPid, callerUid);
@@ -3852,6 +3880,12 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
     return 0;
 
 authfail:
+    goto error;
+
+authdeny:
+    goto error;
+
+error:
     remoteDispatchAuthError(rerr);
     virMutexUnlock(&client->lock);
     return -1;
@@ -3875,6 +3909,9 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
     PolKitResult pkresult;
     DBusError err;
     const char *action;
+    char ident[100];
+
+    memset(ident, 0, sizeof ident);
 
     virMutexLock(&server->lock);
     virMutexLock(&client->lock);
@@ -3895,6 +3932,12 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
         goto authfail;
     }
 
+    rv = snprintf(ident, sizeof ident, "pid:%d,uid:%d", callerPid, callerUid);
+    if (rv < 0 || rv >= sizeof ident) {
+        VIR_ERROR(_("Caller identity was too large %d:%d"), callerPid, callerUid);
+        goto authfail;
+    }
+
     VIR_INFO(_("Checking PID %d running as %d"), callerPid, callerUid);
     dbus_error_init(&err);
     if (!(pkcaller = polkit_caller_new_from_pid(server->sysbus,
@@ -3951,7 +3994,7 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
         VIR_ERROR(_("Policy kit denied action %s from pid %d, uid %d, result: %s"),
                   action, callerPid, callerUid,
                   polkit_result_to_string_representation(pkresult));
-        goto authfail;
+        goto authdeny;
     }
     VIR_INFO(_("Policy allowed action %s from pid %d, uid %d, result %s"),
              action, callerPid, callerUid,
@@ -3963,6 +4006,12 @@ remoteDispatchAuthPolkit (struct qemud_server *server,
     return 0;
 
 authfail:
+    goto error;
+
+authdeny:
+    goto error;
+
+error:
     remoteDispatchAuthError(rerr);
     virMutexUnlock(&client->lock);
     return -1;
-- 
1.7.2.2


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