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qemuDomainDetachDeviceUnlink: Don't unlink files we haven't created 

Even though there are several checks before calling this function
and for some scenarios we don't call it at all (e.g. on disk hot
unplug), it may be possible to sneak in some weird files (e.g. if
domain would have RNG with /dev/shm/some_file as its backend). No
matter how improbable, we shouldn't unlink it as we would be
unlinking a file from the host which we haven't created in the
first place.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cedric Bosdonnat <cbosdonnat@suse.com>
This commit is contained in:
Michal Privoznik 2017-04-28 13:17:04 +02:00
parent b3418f36be
commit 2f0b3b103b
1 changed files with 76 additions and 10 deletions
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86
src/qemu/qemu_domain.c
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@ -8474,14 +8474,32 @@ qemuDomainDetachDeviceUnlinkHelper(pid_t pid ATTRIBUTE_UNUSED,
static int
qemuDomainDetachDeviceUnlink(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
virDomainObjPtr vm,
const char *file)
const char *file,
char * const *devMountsPath,
size_t ndevMountsPath)
{
if (virProcessRunInMountNamespace(vm->pid,
qemuDomainDetachDeviceUnlinkHelper,
(void *)file) < 0)
return -1;
int ret = -1;
size_t i;
return 0;
if (STRPREFIX(file, DEVPREFIX)) {
for (i = 0; i < ndevMountsPath; i++) {
if (STREQ(devMountsPath[i], "/dev"))
continue;
if (STRPREFIX(file, devMountsPath[i]))
break;
}
if (i == ndevMountsPath) {
if (virProcessRunInMountNamespace(vm->pid,
qemuDomainDetachDeviceUnlinkHelper,
(void *)file) < 0)
goto cleanup;
}
}
ret = 0;
cleanup:
return ret;
}
@ -8600,6 +8618,9 @@ qemuDomainNamespaceTeardownHostdev(virQEMUDriverPtr driver,
virDomainObjPtr vm,
virDomainHostdevDefPtr hostdev)
{
virQEMUDriverConfigPtr cfg = NULL;
char **devMountsPath = NULL;
size_t ndevMountsPath = 0;
int ret = -1;
char **path = NULL;
size_t i, npaths = 0;
@ -8611,8 +8632,15 @@ qemuDomainNamespaceTeardownHostdev(virQEMUDriverPtr driver,
&npaths, &path, NULL) < 0)
goto cleanup;
cfg = virQEMUDriverGetConfig(driver);
if (qemuDomainGetPreservedMounts(cfg, vm,
&devMountsPath, NULL,
&ndevMountsPath) < 0)
goto cleanup;
for (i = 0; i < npaths; i++) {
if (qemuDomainDetachDeviceUnlink(driver, vm, path[i]) < 0)
if (qemuDomainDetachDeviceUnlink(driver, vm, path[i],
devMountsPath, ndevMountsPath) < 0)
goto cleanup;
}
@ -8621,6 +8649,8 @@ qemuDomainNamespaceTeardownHostdev(virQEMUDriverPtr driver,
for (i = 0; i < npaths; i++)
VIR_FREE(path[i]);
VIR_FREE(path);
virStringListFreeCount(devMountsPath, ndevMountsPath);
virObjectUnref(cfg);
return ret;
}
@ -8663,6 +8693,9 @@ qemuDomainNamespaceTeardownMemory(virQEMUDriverPtr driver,
virDomainObjPtr vm,
virDomainMemoryDefPtr mem)
{
virQEMUDriverConfigPtr cfg = NULL;
char **devMountsPath = NULL;
size_t ndevMountsPath = 0;
int ret = -1;
if (mem->model != VIR_DOMAIN_MEMORY_MODEL_NVDIMM)
@ -8671,10 +8704,19 @@ qemuDomainNamespaceTeardownMemory(virQEMUDriverPtr driver,
if (!qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT))
return 0;
if (qemuDomainDetachDeviceUnlink(driver, vm, mem->nvdimmPath) < 0)
cfg = virQEMUDriverGetConfig(driver);
if (qemuDomainGetPreservedMounts(cfg, vm,
&devMountsPath, NULL,
&ndevMountsPath) < 0)
goto cleanup;
if (qemuDomainDetachDeviceUnlink(driver, vm, mem->nvdimmPath,
devMountsPath, ndevMountsPath) < 0)
goto cleanup;
ret = 0;
cleanup:
virStringListFreeCount(devMountsPath, ndevMountsPath);
virObjectUnref(cfg);
return ret;
}
@ -8722,6 +8764,9 @@ qemuDomainNamespaceTeardownChardev(virQEMUDriverPtr driver,
virDomainObjPtr vm,
virDomainChrDefPtr chr)
{
virQEMUDriverConfigPtr cfg = NULL;
char **devMountsPath = NULL;
size_t ndevMountsPath = 0;
int ret = -1;
const char *path = NULL;
@ -8733,11 +8778,20 @@ qemuDomainNamespaceTeardownChardev(virQEMUDriverPtr driver,
path = chr->source->data.file.path;
if (qemuDomainDetachDeviceUnlink(driver, vm, path) < 0)
cfg = virQEMUDriverGetConfig(driver);
if (qemuDomainGetPreservedMounts(cfg, vm,
&devMountsPath, NULL,
&ndevMountsPath) < 0)
goto cleanup;
if (qemuDomainDetachDeviceUnlink(driver, vm, path,
devMountsPath, ndevMountsPath) < 0)
goto cleanup;
ret = 0;
cleanup:
virStringListFreeCount(devMountsPath, ndevMountsPath);
virObjectUnref(cfg);
return ret;
}
@ -8791,6 +8845,9 @@ qemuDomainNamespaceTeardownRNG(virQEMUDriverPtr driver,
virDomainObjPtr vm,
virDomainRNGDefPtr rng)
{
virQEMUDriverConfigPtr cfg = NULL;
char **devMountsPath = NULL;
size_t ndevMountsPath = 0;
int ret = -1;
const char *path = NULL;
@ -8808,11 +8865,20 @@ qemuDomainNamespaceTeardownRNG(virQEMUDriverPtr driver,
goto cleanup;
}
if (qemuDomainDetachDeviceUnlink(driver, vm, path) < 0)
cfg = virQEMUDriverGetConfig(driver);
if (qemuDomainGetPreservedMounts(cfg, vm,
&devMountsPath, NULL,
&ndevMountsPath) < 0)
goto cleanup;
if (qemuDomainDetachDeviceUnlink(driver, vm, path,
devMountsPath, ndevMountsPath) < 0)
goto cleanup;
ret = 0;
cleanup:
virStringListFreeCount(devMountsPath, ndevMountsPath);
virObjectUnref(cfg);
return ret;
}