File 5fc590a-CVE-2013-6456.patch of Package libvirt.4601
From f639b2d17ce935b650bb2aca7bdd8d727cab8b02 Mon Sep 17 00:00:00 2001
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Thu, 30 Jan 2014 17:58:36 +0000
Subject: [PATCH 14/14] CVE-2013-6456: Avoid unsafe use of /proc/$PID/root in
LXC hotunplug code
Rewrite multiple hotunplug functions to to use the
virProcessRunInMountNamespace helper. This avoids
risk of a malicious guest replacing /dev with an absolute
symlink, tricking the driver into changing the host OS
filesystem.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 5fc590ad9f4071350a8df4d567ba88baacc8334d)
---
src/lxc/lxc_driver.c | 79 ++++++++++++++++++++++++++--------------------------
1 file changed, 39 insertions(+), 40 deletions(-)
Index: libvirt-1.1.2/src/lxc/lxc_driver.c
===================================================================
--- libvirt-1.1.2.orig/src/lxc/lxc_driver.c
+++ libvirt-1.1.2/src/lxc/lxc_driver.c
@@ -3176,6 +3176,39 @@ lxcDomainAttachDeviceMknod(virLXCDriverP
static int
+lxcDomainAttachDeviceUnlinkHelper(pid_t pid ATTRIBUTE_UNUSED,
+ void *opaque)
+{
+ const char *path = opaque;
+
+ VIR_DEBUG("Unlinking %s", path);
+ if (unlink(path) < 0 && errno != ENOENT) {
+ virReportSystemError(errno,
+ _("Unable to remove device %s"), path);
+ return -1;
+ }
+
+ return 0;
+}
+
+
+static int
+lxcDomainAttachDeviceUnlink(virDomainObjPtr vm,
+ char *file)
+{
+ virLXCDomainObjPrivatePtr priv = vm->privateData;
+
+ if (virProcessRunInMountNamespace(priv->initpid,
+ lxcDomainAttachDeviceUnlinkHelper,
+ file) < 0) {
+ return -1;
+ }
+
+ return 0;
+}
+
+
+static int
lxcDomainAttachDeviceDiskLive(virLXCDriverPtr driver,
virDomainObjPtr vm,
virDomainDeviceDefPtr dev)
@@ -3766,8 +3799,7 @@ lxcDomainDetachDeviceDiskLive(virDomainO
def = vm->def->disks[idx];
- if (virAsprintf(&dst, "/proc/%llu/root/dev/%s",
- (unsigned long long)priv->initpid, def->dst) < 0)
+ if (virAsprintf(&dst, "/dev/%s", def->dst) < 0)
goto cleanup;
if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_DEVICES)) {
@@ -3776,11 +3808,8 @@ lxcDomainDetachDeviceDiskLive(virDomainO
goto cleanup;
}
- VIR_DEBUG("Unlinking %s (backed by %s)", dst, def->src);
- if (unlink(dst) < 0 && errno != ENOENT) {
+ if (lxcDomainAttachDeviceUnlink(vm, dst) < 0) {
virDomainAuditDisk(vm, def->src, NULL, "detach", false);
- virReportSystemError(errno,
- _("Unable to remove device %s"), dst);
goto cleanup;
}
virDomainAuditDisk(vm, def->src, NULL, "detach", true);
@@ -3875,7 +3904,6 @@ lxcDomainDetachDeviceHostdevUSBLive(virL
virDomainHostdevDefPtr def = NULL;
int idx, ret = -1;
char *dst = NULL;
- char *vroot;
virUSBDevicePtr usb = NULL;
if ((idx = virDomainHostdevFind(vm->def,
@@ -3886,12 +3914,7 @@ lxcDomainDetachDeviceHostdevUSBLive(virL
goto cleanup;
}
- if (virAsprintf(&vroot, "/proc/%llu/root",
- (unsigned long long)priv->initpid) < 0)
- goto cleanup;
-
- if (virAsprintf(&dst, "%s/dev/bus/usb/%03d/%03d",
- vroot,
+ if (virAsprintf(&dst, "/dev/bus/usb/%03d/%03d",
def->source.subsys.u.usb.bus,
def->source.subsys.u.usb.device) < 0)
goto cleanup;
@@ -3906,11 +3929,8 @@ lxcDomainDetachDeviceHostdevUSBLive(virL
def->source.subsys.u.usb.device, NULL)))
goto cleanup;
- VIR_DEBUG("Unlinking %s", dst);
- if (unlink(dst) < 0 && errno != ENOENT) {
+ if (lxcDomainAttachDeviceUnlink(vm, dst) < 0) {
virDomainAuditHostdev(vm, def, "detach", false);
- virReportSystemError(errno,
- _("Unable to remove device %s"), dst);
goto cleanup;
}
virDomainAuditHostdev(vm, def, "detach", true);
@@ -3944,7 +3964,6 @@ lxcDomainDetachDeviceHostdevStorageLive(
virLXCDomainObjPrivatePtr priv = vm->privateData;
virDomainHostdevDefPtr def = NULL;
int idx, ret = -1;
- char *dst = NULL;
if (!priv->initpid) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
@@ -3961,22 +3980,14 @@ lxcDomainDetachDeviceHostdevStorageLive(
goto cleanup;
}
- if (virAsprintf(&dst, "/proc/%llu/root/%s",
- (unsigned long long)priv->initpid,
- def->source.caps.u.storage.block) < 0)
- goto cleanup;
-
if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_DEVICES)) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("devices cgroup isn't mounted"));
goto cleanup;
}
- VIR_DEBUG("Unlinking %s", dst);
- if (unlink(dst) < 0 && errno != ENOENT) {
+ if (lxcDomainAttachDeviceUnlink(vm, def->source.caps.u.storage.block) < 0) {
virDomainAuditHostdev(vm, def, "detach", false);
- virReportSystemError(errno,
- _("Unable to remove device %s"), dst);
goto cleanup;
}
virDomainAuditHostdev(vm, def, "detach", true);
@@ -3991,7 +4002,6 @@ lxcDomainDetachDeviceHostdevStorageLive(
ret = 0;
cleanup:
- VIR_FREE(dst);
return ret;
}
@@ -4003,7 +4013,6 @@ lxcDomainDetachDeviceHostdevMiscLive(vir
virLXCDomainObjPrivatePtr priv = vm->privateData;
virDomainHostdevDefPtr def = NULL;
int idx, ret = -1;
- char *dst = NULL;
if (!priv->initpid) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
@@ -4020,22 +4029,14 @@ lxcDomainDetachDeviceHostdevMiscLive(vir
goto cleanup;
}
- if (virAsprintf(&dst, "/proc/%llu/root/%s",
- (unsigned long long)priv->initpid,
- def->source.caps.u.misc.chardev) < 0)
- goto cleanup;
-
if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_DEVICES)) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("devices cgroup isn't mounted"));
goto cleanup;
}
- VIR_DEBUG("Unlinking %s", dst);
- if (unlink(dst) < 0 && errno != ENOENT) {
+ if (lxcDomainAttachDeviceUnlink(vm, def->source.caps.u.misc.chardev) < 0) {
virDomainAuditHostdev(vm, def, "detach", false);
- virReportSystemError(errno,
- _("Unable to remove device %s"), dst);
goto cleanup;
}
virDomainAuditHostdev(vm, def, "detach", true);
@@ -4050,7 +4051,6 @@ lxcDomainDetachDeviceHostdevMiscLive(vir
ret = 0;
cleanup:
- VIR_FREE(dst);
return ret;
}
