qemu: remove use of qemuDomainObjBeginJobWithAgent()

This function will be removed in a future commit because it allows the
caller to acquire both monitor and agent jobs at the same time. Holding
both job types creates a vulnerability to denial of service from a
malicious guest agent.

qemuDomainSetVcpusFlags() always passes NONE for either the monitor job
or the agent job (and thus is not vulnerable to the DoS), so we can
simply replace this function with the functions for acquiring the
appropriate type of job.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
This commit is contained in:
Jonathon Jongsma 2019-12-05 10:08:56 -06:00 committed by Michal Privoznik
parent e005c95f56
commit ffa5066a49

View File

@ -5039,8 +5039,6 @@ qemuDomainSetVcpusFlags(virDomainPtr dom,
virDomainDefPtr persistentDef;
bool hotpluggable = !!(flags & VIR_DOMAIN_VCPU_HOTPLUGGABLE);
bool useAgent = !!(flags & VIR_DOMAIN_VCPU_GUEST);
qemuDomainJob job = QEMU_JOB_NONE;
qemuDomainAgentJob agentJob = QEMU_AGENT_JOB_NONE;
int ret = -1;
virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
@ -5055,13 +5053,14 @@ qemuDomainSetVcpusFlags(virDomainPtr dom,
if (virDomainSetVcpusFlagsEnsureACL(dom->conn, vm->def, flags) < 0)
goto cleanup;
if (useAgent)
agentJob = QEMU_AGENT_JOB_MODIFY;
else
job = QEMU_JOB_MODIFY;
if (qemuDomainObjBeginJobWithAgent(driver, vm, job, agentJob) < 0)
goto cleanup;
if (useAgent) {
if (qemuDomainObjBeginAgentJob(driver, vm, QEMU_AGENT_JOB_MODIFY) < 0)
goto cleanup;
} else {
if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
goto cleanup;
}
if (virDomainObjGetDefs(vm, flags, &def, &persistentDef) < 0)
goto endjob;
@ -5075,7 +5074,7 @@ qemuDomainSetVcpusFlags(virDomainPtr dom,
nvcpus, hotpluggable);
endjob:
if (agentJob)
if (useAgent)
qemuDomainObjEndAgentJob(vm);
else
qemuDomainObjEndJob(driver, vm);