On 06/04/2013 09:35 PM, Daniel P. Berrange wrote:
> On Thu, May 23, 2013 at 12:06:48PM +0800, Gao feng wrote:
>> This patch introduces new helper function
>> virLXCControllerSetupUserns, in this function,
>> we set the files uid_map and gid_map of the init
>> task of container.
>>
>> lxcContainerSetID is used for creating cred for
>> tasks running in container. Since after setuid/setgid,
>> we may be a new user. This patch calls lxcContainerSetUserns
>> at first to make sure the new created files belong to
>> right user.
>>
>> Signed-off-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
>> ---
>> src/lxc/lxc_container.c | 63 ++++++++++++++++++++++++++++++++--------------
>> src/lxc/lxc_controller.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 110 insertions(+), 18 deletions(-)
>>
>> diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
>> index 618252c..52fcf39 100644
>> --- a/src/lxc/lxc_container.c
>> +++ b/src/lxc/lxc_container.c
>> @@ -335,6 +335,30 @@ int lxcContainerWaitForContinue(int control)
>>
>>
>> /**
>> + * lxcContainerSetID:
>> + *
>> + * This function calls setuid and setgid to create proper
>> + * cred for tasks running in container.
>> + *
>> + * Returns 0 on success or -1 in case of error
>> + */
>> +static int lxcContainerSetID(virDomainDefPtr def)
>> +{
>> + /* Only call virSetUIDGID when user namespace is enabled
>> + * for this container. And user namespace is only enabled
>> + * when nuidmap&ngidmap is not zero */
>> +
>> + if (def->idmap.nuidmap && virSetUIDGID(0, 0) < 0) {
>> + virReportSystemError(errno, "%s",
>> + _("setuid or setgid failed"));
>> + return -1;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +
>> +/**
>> * lxcContainerRenameAndEnableInterfaces:
>> * @nveths: number of interfaces
>> * @veths: interface names
>> @@ -1937,6 +1961,27 @@ static int lxcContainerChild(void *data)
>> cmd = lxcContainerBuildInitCmd(vmDef);
>> virCommandWriteArgLog(cmd, 1);
>>
>> + if (lxcContainerResolveSymlinks(vmDef) < 0)
>> + goto cleanup;
>> +
>> + if (!virFileExists(vmDef->os.init)) {
>> + virReportSystemError(errno,
>> + _("cannot find init path '%s' relative to container root"),
>> + vmDef->os.init);
>> + goto cleanup;
>> + }
>> +
>> + /* Wait for interface devices to show up */
>> + if (lxcContainerWaitForContinue(argv->monitor) < 0) {
>> + virReportSystemError(errno, "%s",
>> + _("Failed to read the container continue message"));
>> + goto cleanup;
>> + }
>> + VIR_DEBUG("Received container continue message");
>> +
>> + if (lxcContainerSetID(vmDef) < 0)
>> + goto cleanup;
>> +
>> root = virDomainGetRootFilesystem(vmDef);
>>
>> if (argv->nttyPaths) {
>> @@ -1962,29 +2007,11 @@ static int lxcContainerChild(void *data)
>> goto cleanup;
>> }
>>
>> - if (lxcContainerResolveSymlinks(vmDef) < 0)
>> - goto cleanup;
>> -
>> if (lxcContainerSetupPivotRoot(vmDef, root,
>> argv->ttyPaths, argv->nttyPaths,
>> argv->securityDriver) < 0)
>> goto cleanup;
>>
>> - if (!virFileExists(vmDef->os.init)) {
>> - virReportSystemError(errno,
>> - _("cannot find init path '%s' relative to container root"),
>> - vmDef->os.init);
>> - goto cleanup;
>> - }
>> -
>> - /* Wait for interface devices to show up */
>> - if (lxcContainerWaitForContinue(argv->monitor) < 0) {
>> - virReportSystemError(errno, "%s",
>> - _("Failed to read the container continue message"));
>> - goto cleanup;
>> - }
>> - VIR_DEBUG("Received container continue message");
>
> Why did you need to move these functions before the lxcContainerSetID
> call ?
lxcContainerSetID is only meaningful after we set idmap for user namespace,
Actually I just move lxcContainerSetID to the top of lxcContainerChild.
It's better to call setuid/setgid as early as we can.
>
>> diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
>> index dfe686b..0a2e3ac 100644
>> --- a/src/lxc/lxc_controller.c
>> +++ b/src/lxc/lxc_controller.c
>> @@ -1122,6 +1122,68 @@ cleanup2:
>> }
>>
>>
>> +static int
>> +virLXCControllerSetupUsernsMap(virDomainIdMapEntryPtr map,
>> + char *path,
>> + int num)
>> +{
>> + virBuffer map_value = VIR_BUFFER_INITIALIZER;
>> + int i, ret = -1;
>> +
>> + for (i = 0; i < num; i++)
>> + virBufferAsprintf(&map_value, "%u %u %u\n",
>> + map[i].start, map[i].target, map[i].count);
>> +
>
> You need to check
>
> virBufferError()
>
> to see if OOM has occured here.
>
sure,
I will wait for your related patches being merged and then update this patchset.
Thanks
Gao
>> + if (virFileWriteStr(path, virBufferCurrentContent(&map_value), 0) < 0) {
>> + virReportSystemError(errno, _("unable write to %s"), path);
>> + goto cleanup;
>> + }
>> + ret = 0;
>> +
>> +cleanup:
>> + virBufferFreeAndReset(&map_value);
>> + return ret;
>> +}
>
>
> Daniel
>
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