[libvirt] [PATCH] Solaris least privilege support
john.levon at sun.com
john.levon at sun.com
Tue Jan 20 19:13:38 UTC 2009
# HG changeset patch
# User john.levon at sun.com
# Date 1232478815 28800
# Node ID 9c7ef175f3a797ecc3ffa6b1fed5a27d1814838c
# Parent ce76623e857f5bb2cf3af8414335f891fd7902b7
Solaris least privilege support
On Solaris dom0, virtd runs as a privilege barrier: all libvirt
connections are routed through it, and it performs the relevant
privilege checks for any clients.
Signed-off-by: John Levon <john.levon at sun.com>
diff --git a/qemud/qemud.c b/qemud/qemud.c
--- a/qemud/qemud.c
+++ b/qemud/qemud.c
@@ -84,6 +84,39 @@
#endif
+#ifdef __sun
+#include <ucred.h>
+#include <priv.h>
+
+#ifndef PRIV_VIRT_MANAGE
+#define PRIV_VIRT_MANAGE ((const char *)"virt_manage")
+#endif
+
+#ifndef PRIV_XVM_CONTROL
+#define PRIV_XVM_CONTROL ((const char *)"xvm_control")
+#endif
+
+#define PU_RESETGROUPS 0x0001 /* Remove supplemental groups */
+#define PU_CLEARLIMITSET 0x0008 /* L=0 */
+
+extern int __init_daemon_priv(int, uid_t, gid_t, ...);
+
+#define SYSTEM_UID 60
+
+static gid_t unix_sock_gid = 60; /* Not used */
+static int unix_sock_rw_mask = 0666;
+static int unix_sock_ro_mask = 0666;
+
+#else
+
+#define SYSTEM_UID 0
+
+static gid_t unix_sock_gid = 0; /* Only root by default */
+static int unix_sock_rw_mask = 0700; /* Allow user only */
+static int unix_sock_ro_mask = 0777; /* Allow world */
+
+#endif /* __sun */
+
static int godaemon = 0; /* -d: Be a daemon */
static int verbose = 0; /* -v: Verbose mode */
static int timeout = -1; /* -t: Shutdown timeout */
@@ -101,10 +134,6 @@ static char *listen_addr = (char *) LIB
static char *listen_addr = (char *) LIBVIRTD_LISTEN_ADDR;
static char *tls_port = (char *) LIBVIRTD_TLS_PORT;
static char *tcp_port = (char *) LIBVIRTD_TCP_PORT;
-
-static gid_t unix_sock_gid = 0; /* Only root by default */
-static int unix_sock_rw_mask = 0700; /* Allow user only */
-static int unix_sock_ro_mask = 0777; /* Allow world */
#if HAVE_POLKIT
static int auth_unix_rw = REMOTE_AUTH_POLKIT;
@@ -638,10 +667,11 @@ static int qemudInitPaths(struct qemud_s
static int qemudInitPaths(struct qemud_server *server,
char *sockname,
char *roSockname,
- int maxlen) {
+ int maxlen)
+{
uid_t uid = geteuid();
- if (!uid) {
+ if (uid == SYSTEM_UID) {
if (snprintf (sockname, maxlen, "%s/run/libvirt/libvirt-sock",
LOCAL_STATE_DIR) >= maxlen)
goto snprintf_error;
@@ -1110,6 +1140,29 @@ static int qemudDispatchServer(struct qe
return -1;
}
+#ifdef __sun
+ {
+ ucred_t *ucred = NULL;
+ const priv_set_t *privs;
+
+ if (getpeerucred (fd, &ucred) == -1 ||
+ (privs = ucred_getprivset (ucred, PRIV_EFFECTIVE)) == NULL) {
+ if (ucred != NULL)
+ ucred_free (ucred);
+ close (fd);
+ return -1;
+ }
+
+ if (!priv_ismember (privs, PRIV_VIRT_MANAGE)) {
+ ucred_free (ucred);
+ close (fd);
+ return -1;
+ }
+
+ ucred_free (ucred);
+ }
+#endif /* __sun */
+
/* Disable Nagle. Unix sockets will ignore this. */
setsockopt (fd, IPPROTO_TCP, TCP_NODELAY, (void *)&no_slow_start,
sizeof no_slow_start);
@@ -2257,6 +2310,30 @@ version (const char *argv0)
{
printf ("%s (%s) %s\n", argv0, PACKAGE_NAME, PACKAGE_VERSION);
}
+
+#ifdef __sun
+static int
+qemudSetupPrivs (void)
+{
+ chown ("/var/run/libvirt", SYSTEM_UID, SYSTEM_UID);
+
+ if (__init_daemon_priv (PU_RESETGROUPS | PU_CLEARLIMITSET,
+ SYSTEM_UID, SYSTEM_UID, PRIV_XVM_CONTROL, NULL)) {
+ fprintf (stderr, "additional privileges are required\n");
+ return -1;
+ }
+
+ if (priv_set (PRIV_OFF, PRIV_ALLSETS, PRIV_FILE_LINK_ANY, PRIV_PROC_INFO,
+ PRIV_PROC_SESSION, PRIV_PROC_EXEC, PRIV_PROC_FORK, NULL)) {
+ fprintf (stderr, "failed to set reduced privileges\n");
+ return -1;
+ }
+
+ return 0;
+}
+#else
+#define qemudSetupPrivs() 0
+#endif
/* Print command-line usage. */
static void
@@ -2435,6 +2512,21 @@ int main(int argc, char **argv) {
sig_action.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sig_action, NULL);
+ /* Ensure the rundir exists (on tmpfs on some systems) */
+ if (geteuid () == 0) {
+ const char *rundir = LOCAL_STATE_DIR "/run/libvirt";
+
+ if (mkdir (rundir, 0755)) {
+ if (errno != EEXIST) {
+ VIR_ERROR0 (_("unable to create rundir"));
+ return -1;
+ }
+ }
+ }
+
+ if (qemudSetupPrivs() < 0)
+ goto error2;
+
if (!(server = qemudInitialize(sigpipe[0]))) {
ret = 2;
goto error2;
diff --git a/src/remote_internal.c b/src/remote_internal.c
--- a/src/remote_internal.c
+++ b/src/remote_internal.c
@@ -885,18 +885,21 @@ remoteOpen (virConnectPtr conn,
}
/*
- * If URI is NULL, then do a UNIX connection
- * possibly auto-spawning unprivileged server
- * and probe remote server for URI
+ * If URI is NULL, then do a UNIX connection possibly auto-spawning
+ * unprivileged server and probe remote server for URI. On Solaris,
+ * this isn't supported, but we may be privileged enough to connect
+ * to the UNIX socket anyway.
*/
if (!conn->uri) {
DEBUG0("Auto-probe remote URI");
rflags |= VIR_DRV_OPEN_REMOTE_UNIX;
+#ifndef __sun
if (getuid() > 0) {
DEBUG0("Auto-spawn user daemon instance");
rflags |= VIR_DRV_OPEN_REMOTE_USER;
rflags |= VIR_DRV_OPEN_REMOTE_AUTOSTART;
}
+#endif
}
priv->sock = -1;
diff --git a/src/xen_internal.c b/src/xen_internal.c
--- a/src/xen_internal.c
+++ b/src/xen_internal.c
@@ -26,6 +26,17 @@
#include <errno.h>
#include <sys/utsname.h>
+#ifdef __sun
+#include <sys/systeminfo.h>
+
+#include <priv.h>
+
+#ifndef PRIV_XVM_CONTROL
+#define PRIV_XVM_CONTROL ((const char *)"xvm_control")
+#endif
+
+#endif /* __sun */
+
/* required for dom0_getdomaininfo_t */
#include <xen/dom0_ops.h>
#include <xen/version.h>
@@ -35,10 +46,6 @@
#ifdef HAVE_XEN_SYS_PRIVCMD_H
#include <xen/sys/privcmd.h>
#endif
-#endif
-
-#ifdef __sun
-#include <sys/systeminfo.h>
#endif
/* required for shutdown flags */
@@ -3393,3 +3400,17 @@ xenHypervisorGetVcpuMax(virDomainPtr dom
return maxcpu;
}
+/**
+ * xenHavePrivilege()
+ *
+ * Return true if the current process should be able to connect to Xen.
+ */
+int
+xenHavePrivilege()
+{
+#ifdef __sun
+ return priv_ineffect (PRIV_XVM_CONTROL);
+#else
+ return getuid () == 0;
+#endif
+}
diff --git a/src/xen_internal.h b/src/xen_internal.h
--- a/src/xen_internal.h
+++ b/src/xen_internal.h
@@ -104,4 +104,6 @@ int xenHypervisorNodeGetCellsFreeMem
int startCell,
int maxCells);
+int xenHavePrivilege(void);
+
#endif /* __VIR_XEN_INTERNAL_H__ */
diff --git a/src/xen_unified.c b/src/xen_unified.c
--- a/src/xen_unified.c
+++ b/src/xen_unified.c
@@ -65,6 +65,8 @@ static struct xenUnifiedDriver *drivers[
#endif
};
+static int inside_daemon;
+
#define xenUnifiedError(conn, code, fmt...) \
virReportErrorHelper(conn, VIR_FROM_XEN, code, __FILE__, \
__FUNCTION__, __LINE__, fmt)
@@ -195,6 +197,21 @@ done:
return(res);
}
+#ifdef WITH_LIBVIRTD
+
+static int
+xenInitialize (void)
+{
+ inside_daemon = 1;
+ return 0;
+}
+
+static virStateDriver state_driver = {
+ .initialize = xenInitialize,
+};
+
+#endif
+
/*----- Dispatch functions. -----*/
/* These dispatch functions follow the model used historically
@@ -231,6 +248,15 @@ xenUnifiedOpen (virConnectPtr conn, virC
xenUnifiedPrivatePtr priv;
virDomainEventCallbackListPtr cbList;
+#ifdef __sun
+ /*
+ * Only the libvirtd instance can open this driver.
+ * Everything else falls back to the remote driver.
+ */
+ if (!inside_daemon)
+ return VIR_DRV_OPEN_DECLINED;
+#endif
+
if (conn->uri == NULL) {
if (!xenUnifiedProbe())
return VIR_DRV_OPEN_DECLINED;
@@ -283,8 +309,8 @@ xenUnifiedOpen (virConnectPtr conn, virC
priv->proxy = -1;
- /* Hypervisor is only run as root & required to succeed */
- if (getuid() == 0) {
+ /* Hypervisor is only run with privilege & required to succeed */
+ if (xenHavePrivilege()) {
DEBUG0("Trying hypervisor sub-driver");
if (drivers[XEN_UNIFIED_HYPERVISOR_OFFSET]->open(conn, auth, flags) ==
VIR_DRV_OPEN_SUCCESS) {
@@ -293,7 +319,7 @@ xenUnifiedOpen (virConnectPtr conn, virC
}
}
- /* XenD is required to suceed if root.
+ /* XenD is required to succeed if privileged.
* If it fails as non-root, then the proxy driver may take over
*/
DEBUG0("Trying XenD sub-driver");
@@ -318,12 +344,12 @@ xenUnifiedOpen (virConnectPtr conn, virC
DEBUG0("Activated XS sub-driver");
priv->opened[XEN_UNIFIED_XS_OFFSET] = 1;
} else {
- if (getuid() == 0)
- goto fail; /* XS is mandatory as root */
+ if (xenHavePrivilege())
+ goto fail; /* XS is mandatory when privileged */
}
} else {
- if (getuid() == 0) {
- goto fail; /* XenD is mandatory as root */
+ if (xenHavePrivilege()) {
+ goto fail; /* XenD is mandatory when privileged */
} else {
#if WITH_PROXY
DEBUG0("Trying proxy sub-driver");
@@ -1472,6 +1498,10 @@ xenRegister (void)
(void) xenHypervisorInit ();
(void) xenXMInit ();
+#ifdef WITH_LIBVIRTD
+ if (virRegisterStateDriver (&state_driver) == -1) return -1;
+#endif
+
return virRegisterDriver (&xenUnifiedDriver);
}
diff --git a/src/xend_internal.c b/src/xend_internal.c
--- a/src/xend_internal.c
+++ b/src/xend_internal.c
@@ -42,7 +42,7 @@
#include "buf.h"
#include "uuid.h"
#include "xen_unified.h"
-#include "xen_internal.h" /* for DOM0_INTERFACE_VERSION */
+#include "xen_internal.h"
#include "xs_internal.h" /* To extract VNC port & Serial console TTY */
#include "memory.h"
@@ -159,9 +159,10 @@ do_connect(virConnectPtr xend)
s = -1;
/*
- * Connecting to XenD as root is mandatory, so log this error
+ * Connecting to XenD when privileged is mandatory, so log this
+ * error
*/
- if (getuid() == 0) {
+ if (xenHavePrivilege()) {
virXendError(xend, VIR_ERR_INTERNAL_ERROR,
"%s", _("failed to connect to xend"));
}
diff --git a/src/xs_internal.c b/src/xs_internal.c
--- a/src/xs_internal.c
+++ b/src/xs_internal.c
@@ -35,7 +35,7 @@
#include "uuid.h"
#include "xen_unified.h"
#include "xs_internal.h"
-#include "xen_internal.h" /* for xenHypervisorCheckID */
+#include "xen_internal.h"
#ifdef __linux__
#define XEN_HYPERVISOR_SOCKET "/proc/xen/privcmd"
@@ -299,11 +299,11 @@ xenStoreOpen(virConnectPtr conn,
if (priv->xshandle == NULL) {
/*
- * not being able to connect via the socket as a normal user
- * is rather normal, this should fallback to the proxy (or
+ * not being able to connect via the socket as an unprivileged
+ * user is rather normal, this should fallback to the proxy (or
* remote) mechanism.
*/
- if (getuid() == 0) {
+ if (xenHavePrivilege()) {
virXenStoreError(NULL, VIR_ERR_NO_XEN,
"%s", _("failed to connect to Xen Store"));
}
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