10:39 a.m.
Rewrite lxcDomainAttachDeviceHostdevSubsysUSBLive function
to use the virProcessRunInMountNamespace helper. This avoids
risk of a malicious guest replacing /dev with a absolute
symlink, tricking the driver into changing the host OS
filesystem.
Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com>
---
src/lxc/lxc_driver.c | 73 ++++++++++++++++------------------------------------
1 file changed, 22 insertions(+), 51 deletions(-)
diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index 409f8b7..30aa31f 100644
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -3715,6 +3715,13 @@ lxcDomainAttachDeviceMknodHelper(pid_t pid ATTRIBUTE_UNUSED,
def->src = tmpsrc;
} break;
+ case VIR_DOMAIN_DEVICE_HOSTDEV: {
+ virDomainHostdevDefPtr def = data->def->data.hostdev;
+ if (virSecurityManagerSetHostdevLabel(data->driver->securityManager,
+ data->vm->def, def, NULL) < 0)
+ goto cleanup;
+ } break;
+
default:
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Unexpected device type %d"),
@@ -4009,13 +4016,8 @@ lxcDomainAttachDeviceHostdevSubsysUSBLive(virLXCDriverPtr driver,
virLXCDomainObjPrivatePtr priv = vm->privateData;
virDomainHostdevDefPtr def = dev->data.hostdev;
int ret = -1;
- char *vroot = NULL;
char *src = NULL;
- char *dstdir = NULL;
- char *dstfile = NULL;
struct stat sb;
- mode_t mode;
- bool created = false;
virUSBDevicePtr usb = NULL;
if (virDomainHostdevFind(vm->def, def, NULL) >= 0) {
@@ -4024,27 +4026,13 @@ lxcDomainAttachDeviceHostdevSubsysUSBLive(virLXCDriverPtr driver,
return -1;
}
- if (virAsprintf(&vroot, "/proc/%llu/root",
- (unsigned long long)priv->initpid) < 0)
- goto cleanup;
-
- if (virAsprintf(&dstdir, "%s/dev/bus/usb/%03d",
- vroot,
- def->source.subsys.u.usb.bus) < 0)
- goto cleanup;
-
- if (virAsprintf(&dstfile, "%s/%03d",
- dstdir,
- def->source.subsys.u.usb.device) < 0)
- goto cleanup;
-
if (virAsprintf(&src, "/dev/bus/usb/%03d/%03d",
def->source.subsys.u.usb.bus,
def->source.subsys.u.usb.device) < 0)
goto cleanup;
if (!(usb = virUSBDeviceNew(def->source.subsys.u.usb.bus,
- def->source.subsys.u.usb.device, vroot)))
+ def->source.subsys.u.usb.device, NULL)))
goto cleanup;
if (stat(src, &sb) < 0) {
@@ -4060,53 +4048,36 @@ lxcDomainAttachDeviceHostdevSubsysUSBLive(virLXCDriverPtr driver,
goto cleanup;
}
- mode = 0700 | S_IFCHR;
-
if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0)
goto cleanup;
- if (virFileMakePath(dstdir) < 0) {
- virReportSystemError(errno,
- _("Unable to create %s"), dstdir);
- goto cleanup;
- }
-
- VIR_DEBUG("Creating dev %s (%d,%d)",
- dstfile, major(sb.st_rdev), minor(sb.st_rdev));
- if (mknod(dstfile, mode, sb.st_rdev) < 0) {
- virReportSystemError(errno,
- _("Unable to create device %s"),
- dstfile);
- goto cleanup;
- }
- created = true;
-
- if (lxcContainerChown(vm->def, dstfile) < 0)
- goto cleanup;
-
- if (virSecurityManagerSetHostdevLabel(driver->securityManager,
- vm->def, def, vroot) < 0)
- goto cleanup;
-
if (virUSBDeviceFileIterate(usb,
virLXCSetupHostUsbDeviceCgroup,
priv->cgroup) < 0)
goto cleanup;
+ if (lxcDomainAttachDeviceMknod(driver,
+ 0700 | S_IFCHR,
+ sb.st_rdev,
+ vm,
+ dev,
+ src) < 0) {
+ if (virUSBDeviceFileIterate(usb,
+ virLXCTeardownHostUsbDeviceCgroup,
+ priv->cgroup) < 0)
+ VIR_WARN("cannot deny device %s for domain %s",
+ src, vm->def->name);
+ goto cleanup;
+ }
+
vm->def->hostdevs[vm->def->nhostdevs++] = def;
ret = 0;
cleanup:
virDomainAuditHostdev(vm, def, "attach", ret == 0);
- if (ret < 0 && created)
- unlink(dstfile);
-
virUSBDeviceFree(usb);
VIR_FREE(src);
- VIR_FREE(dstfile);
- VIR_FREE(dstdir);
- VIR_FREE(vroot);
return ret;
}
--
1.8.5.3