Only allow the UNIX transport in remote driver when setuid

We don't know enough about quality of external libraries used
for non-UNIX transports, nor do we want to spawn external
commands when setuid. Restrict to the bare minimum which is
UNIX transport for local usage. Users shouldn't need to be
running setuid if connecting to remote hypervisors in any
case.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
(cherry picked from commit e22b0232c7b94aefaef87c52c4d626fa532fcce3)

diff --git a/src/libvirt.c b/src/libvirt.c
index 5c65e2a8fa67b2f23a47d51c04706e054a154e37..baa62c44d471c97ee6606cd7deb3810ae1ff08ff 100644 (file)
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -1135,6 +1135,12 @@ do_open(const char *name,
     if (name && name[0] == '\0')
         name = NULL;
 
+    if (!name && virIsSUID()) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("An explicit URI must be provided when setuid"));
+        goto failed;
+    }
+
     /*
      *  If no URI is passed, then check for an environment string if not
      *  available probe the compiled in drivers to find a default hypervisor

diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c
index 67daf792b2152a25cce4cb30ed68d15d31cf362c..b6b629cdf8f8cffadd2da62b293d8f1a92316b90 100644 (file)
--- a/src/remote/remote_driver.c
+++ b/src/remote/remote_driver.c
@@ -488,6 +488,20 @@ doRemoteOpen(virConnectPtr conn,
         transport = trans_unix;
     }
 
+    /*
+     * We don't want to be executing external programs in setuid mode,
+     * so this rules out 'ext' and 'ssh' transports. Exclude libssh
+     * and tls too, since we're not confident the libraries are safe
+     * for setuid usage. Just allow UNIX sockets, since that does
+     * not require any external libraries or command execution
+     */
+    if (virIsSUID() &&
+        transport != trans_unix) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Only Unix socket URI transport is allowed in setuid mode"));
+        return VIR_DRV_OPEN_ERROR;
+    }
+
     /* Local variables which we will initialize. These can
      * get freed in the failed: path.
      */