qemu: driver: Fix qemuDomainHelperGetVcpus for sparse vcpu topologies

ce43cca0e refactored the helper to prepare it for sparse topologies but
forgot to fix the iterator used to fill the structures. This would
result into a weirdly sparse populated array and possible out of bounds
access and crash once sparse vcpu topologies were allowed.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1369988

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 97e2ffc404ab9402c43b93e11cd92f33324ce0b0..671d1ffc2ac6c3716d41baa39ecf0002956f4fc4 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -1477,15 +1477,17 @@ qemuDomainHelperGetVcpus(virDomainObjPtr vm,
     for (i = 0; i < virDomainDefGetVcpusMax(vm->def) && ncpuinfo < maxinfo; i++) {
         virDomainVcpuDefPtr vcpu = virDomainDefGetVcpu(vm->def, i);
         pid_t vcpupid = qemuDomainGetVcpuPid(vm, i);
+        virVcpuInfoPtr vcpuinfo = info + ncpuinfo;
 
         if (!vcpu->online)
             continue;
 
         if (info) {
-            info[i].number = i;
-            info[i].state = VIR_VCPU_RUNNING;
+            vcpuinfo->number = i;
+            vcpuinfo->state = VIR_VCPU_RUNNING;
 
-            if (qemuGetProcessInfo(&(info[i].cpuTime), &(info[i].cpu), NULL,
+            if (qemuGetProcessInfo(&vcpuinfo->cpuTime,
+                                   &vcpuinfo->cpu, NULL,
                                    vm->pid, vcpupid) < 0) {
                 virReportSystemError(errno, "%s",
                                      _("cannot get vCPU placement & pCPU time"));
@@ -1494,7 +1496,7 @@ qemuDomainHelperGetVcpus(virDomainObjPtr vm,
         }
 
         if (cpumaps) {
-            unsigned char *cpumap = VIR_GET_CPUMAP(cpumaps, maplen, i);
+            unsigned char *cpumap = VIR_GET_CPUMAP(cpumaps, maplen, ncpuinfo);
             virBitmapPtr map = NULL;
 
             if (!(map = virProcessGetAffinity(vcpupid)))
@@ -1505,7 +1507,7 @@ qemuDomainHelperGetVcpus(virDomainObjPtr vm,
         }
 
         if (cpuwait) {
-            if (qemuGetSchedInfo(&(cpuwait[i]), vm->pid, vcpupid) < 0)
+            if (qemuGetSchedInfo(&(cpuwait[ncpuinfo]), vm->pid, vcpupid) < 0)
                 return -1;
         }