libvirt/src/qemu/qemu_conf.h
Daniel P. Berrangé 1902356231 qemu: keep capabilities when running QEMU as root
When QEMU uid/gid is set to non-root this is pointless as if we just
used a regular setuid/setgid call, the process will have all its
capabilities cleared anyway by the kernel.

When QEMU uid/gid is set to root, this is almost (always?) never
what people actually want. People make QEMU run as root in order
to access some privileged resource that libvirt doesn't support
yet and this often requires capabilities. As a result they have
to go find the qemu.conf param to turn this off. This is not
viable for libguestfs - they want to control everything via the
XML security label to request running as root regardless of the
qemu.conf settings for user/group.

Clearing capabilities was implemented originally because there
was a proposal in Fedora to change permissions such that root,
with no capabilities would not be able to compromise the system.
ie a locked down root account. This never went anywhere though,
and as a result clearing capabilities when running as root does
not really get us any security benefit AFAICT. The root user
can easily do something like create a cronjob, which will then
faithfully be run with full capabilities, trivially bypassing
the restriction we place.

IOW, our clearing of capabilities is both useless from a security
POV, and breaks valid use cases when people need to run as root.

This removes the clear_emulator_capabilities configuration
option from qemu.conf, and always runs QEMU with capabilities
when root.  The behaviour when non-root is unchanged.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-12-11 16:01:20 +00:00

403 lines
11 KiB
C

/*
* qemu_conf.h: QEMU configuration management
*
* Copyright (C) 2006-2007, 2009-2013 Red Hat, Inc.
* Copyright (C) 2006 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <unistd.h>
#include "virebtables.h"
#include "internal.h"
#include "capabilities.h"
#include "network_conf.h"
#include "domain_conf.h"
#include "checkpoint_conf.h"
#include "snapshot_conf.h"
#include "domain_event.h"
#include "virthread.h"
#include "security/security_manager.h"
#include "virpci.h"
#include "virusb.h"
#include "virscsi.h"
#include "cpu_conf.h"
#include "driver.h"
#include "virportallocator.h"
#include "vircommand.h"
#include "virthreadpool.h"
#include "locking/lock_manager.h"
#include "qemu_capabilities.h"
#include "virclosecallbacks.h"
#include "virhostdev.h"
#include "virfile.h"
#include "virfilecache.h"
#include "virfirmware.h"
#define QEMU_DRIVER_NAME "QEMU"
typedef struct _virQEMUDriver virQEMUDriver;
typedef virQEMUDriver *virQEMUDriverPtr;
typedef struct _virQEMUDriverConfig virQEMUDriverConfig;
typedef virQEMUDriverConfig *virQEMUDriverConfigPtr;
/* Main driver config. The data in these object
* instances is immutable, so can be accessed
* without locking. Threads must, however, hold
* a valid reference on the object to prevent it
* being released while they use it.
*
* eg
* qemuDriverLock(driver);
* virQEMUDriverConfigPtr cfg = virObjectRef(driver->config);
* qemuDriverUnlock(driver);
*
* ...do stuff with 'cfg'..
*
* virObjectUnref(cfg);
*/
struct _virQEMUDriverConfig {
virObject parent;
const char *uri;
uid_t user;
gid_t group;
bool dynamicOwnership;
virBitmapPtr namespaces;
bool rememberOwner;
int cgroupControllers;
char **cgroupDeviceACL;
/* These five directories are ones libvirtd uses (so must be root:root
* to avoid security risk from QEMU processes */
char *configBaseDir;
char *configDir;
char *autostartDir;
char *logDir;
char *swtpmLogDir;
char *stateDir;
char *swtpmStateDir;
char *slirpStateDir;
/* These two directories are ones QEMU processes use (so must match
* the QEMU user/group */
char *libDir;
char *cacheDir;
char *saveDir;
char *snapshotDir;
char *checkpointDir;
char *channelTargetDir;
char *nvramDir;
char *swtpmStorageDir;
char *defaultTLSx509certdir;
bool defaultTLSx509certdirPresent;
bool defaultTLSx509verify;
char *defaultTLSx509secretUUID;
bool vncAutoUnixSocket;
bool vncTLS;
bool vncTLSx509verify;
bool vncTLSx509verifyPresent;
bool vncSASL;
char *vncTLSx509certdir;
char *vncTLSx509secretUUID;
char *vncListen;
char *vncPassword;
char *vncSASLdir;
bool spiceTLS;
char *spiceTLSx509certdir;
bool spiceSASL;
char *spiceSASLdir;
char *spiceListen;
char *spicePassword;
bool spiceAutoUnixSocket;
bool chardevTLS;
char *chardevTLSx509certdir;
bool chardevTLSx509verify;
bool chardevTLSx509verifyPresent;
char *chardevTLSx509secretUUID;
char *migrateTLSx509certdir;
bool migrateTLSx509verify;
bool migrateTLSx509verifyPresent;
char *migrateTLSx509secretUUID;
unsigned int remotePortMin;
unsigned int remotePortMax;
unsigned int webSocketPortMin;
unsigned int webSocketPortMax;
virHugeTLBFSPtr hugetlbfs;
size_t nhugetlbfs;
char *bridgeHelperName;
char *prHelperName;
char *slirpHelperName;
bool macFilter;
bool relaxedACS;
bool vncAllowHostAudio;
bool nogfxAllowHostAudio;
bool setProcessName;
unsigned int maxProcesses;
unsigned int maxFiles;
unsigned int maxThreadsPerProc;
unsigned long long maxCore;
bool dumpGuestCore;
unsigned int maxQueuedJobs;
char **securityDriverNames;
bool securityDefaultConfined;
bool securityRequireConfined;
char *saveImageFormat;
char *dumpImageFormat;
char *snapshotImageFormat;
char *autoDumpPath;
bool autoDumpBypassCache;
bool autoStartBypassCache;
char *lockManagerName;
int keepAliveInterval;
unsigned int keepAliveCount;
int seccompSandbox;
char *migrateHost;
/* The default for -incoming */
char *migrationAddress;
unsigned int migrationPortMin;
unsigned int migrationPortMax;
bool logTimestamp;
bool stdioLogD;
virFirmwarePtr *firmwares;
size_t nfirmwares;
unsigned int glusterDebugLevel;
char *memoryBackingDir;
bool vxhsTLS;
char *vxhsTLSx509certdir;
bool nbdTLS;
char *nbdTLSx509certdir;
uid_t swtpm_user;
gid_t swtpm_group;
char **capabilityfilters;
};
G_DEFINE_AUTOPTR_CLEANUP_FUNC(virQEMUDriverConfig, virObjectUnref);
/* Main driver state */
struct _virQEMUDriver {
virMutex lock;
/* Require lock to get reference on 'config',
* then lockless thereafter */
virQEMUDriverConfigPtr config;
/* pid file FD, ensures two copies of the driver can't use the same root */
int lockFD;
/* Immutable pointer, self-locking APIs */
virThreadPoolPtr workerPool;
/* Atomic increment only */
int lastvmid;
/* Atomic inc/dec only */
unsigned int nactive;
/* Immutable value */
bool privileged;
/* Immutable pointers. Caller must provide locking */
virStateInhibitCallback inhibitCallback;
void *inhibitOpaque;
/* Immutable pointer, self-locking APIs */
virDomainObjListPtr domains;
/* Immutable pointer */
char *qemuImgBinary;
/* Immutable pointer, lockless APIs. Pointless abstraction */
ebtablesContext *ebtables;
/* Require lock to get a reference on the object,
* lockless access thereafter
*/
virCapsPtr caps;
/* Lazy initialized on first use, immutable thereafter.
* Require lock to get the pointer & do optional initialization
*/
virCapsHostNUMAPtr hostnuma;
/* Lazy initialized on first use, immutable thereafter.
* Require lock to get the pointer & do optional initialization
*/
virCPUDefPtr hostcpu;
/* Immutable value */
virArch hostarch;
/* Immutable pointer, Immutable object */
virDomainXMLOptionPtr xmlopt;
/* Immutable pointer, self-locking APIs */
virFileCachePtr qemuCapsCache;
/* Immutable pointer, self-locking APIs */
virObjectEventStatePtr domainEventState;
/* Immutable pointer. self-locking APIs */
virSecurityManagerPtr securityManager;
virHostdevManagerPtr hostdevMgr;
/* Immutable pointer. Unsafe APIs. XXX */
virHashTablePtr sharedDevices;
/* Immutable pointer, immutable object */
virPortAllocatorRangePtr remotePorts;
/* Immutable pointer, immutable object */
virPortAllocatorRangePtr webSocketPorts;
/* Immutable pointer, immutable object */
virPortAllocatorRangePtr migrationPorts;
/* Immutable pointer, lockless APIs*/
virSysinfoDefPtr hostsysinfo;
/* Immutable pointer. lockless access */
virLockManagerPluginPtr lockManager;
/* Immutable pointer, self-clocking APIs */
virCloseCallbacksPtr closeCallbacks;
/* Immutable pointer, self-locking APIs */
virHashAtomicPtr migrationErrors;
};
virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged);
int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
const char *filename,
bool privileged);
int
virQEMUDriverConfigValidate(virQEMUDriverConfigPtr cfg);
int
virQEMUDriverConfigSetDefaults(virQEMUDriverConfigPtr cfg);
virQEMUDriverConfigPtr virQEMUDriverGetConfig(virQEMUDriverPtr driver);
bool virQEMUDriverIsPrivileged(virQEMUDriverPtr driver);
virCapsHostNUMAPtr virQEMUDriverGetHostNUMACaps(virQEMUDriverPtr driver);
virCPUDefPtr virQEMUDriverGetHostCPU(virQEMUDriverPtr driver);
virCapsPtr virQEMUDriverCreateCapabilities(virQEMUDriverPtr driver);
virCapsPtr virQEMUDriverGetCapabilities(virQEMUDriverPtr driver,
bool refresh);
virDomainCapsPtr
virQEMUDriverGetDomainCapabilities(virQEMUDriverPtr driver,
virQEMUCapsPtr qemuCaps,
const char *machine,
virArch arch,
virDomainVirtType virttype);
typedef struct _qemuSharedDeviceEntry qemuSharedDeviceEntry;
typedef qemuSharedDeviceEntry *qemuSharedDeviceEntryPtr;
bool qemuSharedDeviceEntryDomainExists(qemuSharedDeviceEntryPtr entry,
const char *name,
int *idx)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
char *qemuGetSharedDeviceKey(const char *disk_path)
ATTRIBUTE_NONNULL(1);
void qemuSharedDeviceEntryFree(void *payload);
int qemuAddSharedDisk(virQEMUDriverPtr driver,
virDomainDiskDefPtr disk,
const char *name)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
int qemuAddSharedDevice(virQEMUDriverPtr driver,
virDomainDeviceDefPtr dev,
const char *name)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
int qemuRemoveSharedDevice(virQEMUDriverPtr driver,
virDomainDeviceDefPtr dev,
const char *name)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
int qemuRemoveSharedDisk(virQEMUDriverPtr driver,
virDomainDiskDefPtr disk,
const char *name)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
int qemuSetUnprivSGIO(virDomainDeviceDefPtr dev);
int qemuDriverAllocateID(virQEMUDriverPtr driver);
virDomainXMLOptionPtr virQEMUDriverCreateXMLConf(virQEMUDriverPtr driver,
const char *defsecmodel);
int qemuTranslateSnapshotDiskSourcePool(virDomainSnapshotDiskDefPtr def);
char * qemuGetBaseHugepagePath(virHugeTLBFSPtr hugepage);
char * qemuGetDomainHugepagePath(const virDomainDef *def,
virHugeTLBFSPtr hugepage);
int qemuGetDomainHupageMemPath(const virDomainDef *def,
virQEMUDriverConfigPtr cfg,
unsigned long long pagesize,
char **memPath);
void qemuGetMemoryBackingBasePath(virQEMUDriverConfigPtr cfg,
char **path);
int qemuGetMemoryBackingDomainPath(const virDomainDef *def,
virQEMUDriverConfigPtr cfg,
char **path);
int qemuGetMemoryBackingPath(const virDomainDef *def,
virQEMUDriverConfigPtr cfg,
const char *alias,
char **memPath);