[CRIU] [PATCH] cg: don't leak properties when cg dir exists

[Tycho Andersen]

On Thu, Oct 02, 2014 at 07:00:46PM +0400, Andrew Vagin wrote:
> On Thu, Oct 02, 2014 at 09:38:31AM -0500, Tycho Andersen wrote:
> > On Thu, Oct 02, 2014 at 06:00:17PM +0400, Andrew Vagin wrote:
> > > On Wed, Oct 01, 2014 at 08:57:28PM +0000, Tycho Andersen wrote:
> > > > We're using NULL as a sentinel here to indicate that we shouldn't restore any
> > > > cgroup properties. We should make sure that we don't leak this information and
> > > > instead check the n_properties field, which we should also set correctly.
> > > 
> > > Tycho, I beg you to run tests before sending patches.
> > 
> > I thought I did :)
> > 
> > > It's like brushing teeth before bedtime.
> > 
> > One thing that makes it harder than brushing your teeth is that it
> > chmods a lot of files to root in the process. This means I have to
> > fix a whole bunch of things manually before using git again, or it
> > gets really confused.
> 
> It's a good point. Let's fix it.
> Could you give me more details about this problem?
> 
> I think "sudo git clean -dxf test/" should be enough.

It also sets ownership on the makefile, so when do a
`git checkout someotherbranch` I get errors like:

error: unable to unlink old 'test/zdtm/live/static/Makefile' (Permission denied)

Tycho

> Thanks,
> Andrey.
> 
> > 
> > > [root at avagin-fc19-cr criu]# bash test/zdtm.sh static/cgroup00
> > > ================================= CRIU CHECK =================================
> > > Looks good.
> > > Execute zdtm/live/static/cgroup00
> > > ./cgroup00 --pidfile=cgroup00.pid --outfile=cgroup00.out --dirname=cgroup00.test
> > > Dump 1457
> > > Executing pre-restore hook
> > > Cleaning cgclean.OkAnTX
> > > Left there is:
> > > cgroup.clone_children  cgroup.procs  cgroup.sane_behavior  notify_on_release  release_agent  tasks
> > > Restore
> > > Test: zdtm/live/static/cgroup00, Result: FAIL
> > > ==================================== ERROR ====================================
> > > Test: zdtm/live/static/cgroup00, Namespace: 
> > > Dump log   : /root/git/criu/test/dump/static/cgroup00/1457/1/dump.log
> > > --------------------------------- grep Error ---------------------------------
> > > ------------------------------------- END -------------------------------------
> > > Restore log: /root/git/criu/test/dump/static/cgroup00/1457/1/restore.log
> > > --------------------------------- grep Error ---------------------------------
> > > (00.032275)   1457: Error (cgroup.c:943): cg: copying property cpuset.cpus to cpuset////cpuset.cpus failed
> > > (00.032319)   1457: Error (cgroup.c:968): cg: copying prop cpuset.cpus failed
> > > (00.032336)   1457: Error (cgroup.c:1005): cg: Couldn't copy special cgroup properties
> > > (00.032373) Error (cr-restore.c:1820): Restoring FAILED.
> > > (00.039606) Error (cr-restore.c:1177): 1457 exited, status=1
> > > ------------------------------------- END -------------------------------------
> > > ================================= ERROR OVER =================================
> > 
> > For me this test passes, can you paste the entire log file? (really
> > just the next line, there was a \n in my perror message)
> > 
> > Tycho
> > 
> > > Thanks,
> > > Andrey
> > > 
> > > > 
> > > > Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> > > > ---
> > > >  cgroup.c | 15 +++++++--------
> > > >  1 file changed, 7 insertions(+), 8 deletions(-)
> > > > 
> > > > diff --git a/cgroup.c b/cgroup.c
> > > > index 26b0a17..ce49d04 100644
> > > > --- a/cgroup.c
> > > > +++ b/cgroup.c
> > > > @@ -1114,12 +1114,7 @@ static int prepare_cgroup_dir_properties(char *path, int off, CgroupDirEntry **e
> > > >  		size_t off2 = off;
> > > >  
> > > >  		off2 += sprintf(path + off, "/%s", e->dir_name);
> > > > -		/*
> > > > -		 * Check to see if we made e->properties NULL during restore
> > > > -		 * because directory already existed and as such we don't want to
> > > > -		 * change its properties
> > > > -		 */
> > > > -		if (e->properties) {
> > > > +		if (e->n_properties > 0) {
> > > >  			for (j = 0; j < e->n_properties; ++j) {
> > > >  				if (restore_cgroup_prop(e->properties[j], path, off2) < 0)
> > > >  					return -1;
> > > > @@ -1168,7 +1163,7 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
> > > >  		/*
> > > >  		 * Checking to see if file already exists. If not, create it. If
> > > >  		 * it does exist, prevent us from overwriting the properties
> > > > -		 * later by setting the CgroupDirEntry's properties pointer to NULL
> > > > +		 * later by removing the CgroupDirEntry's properties.
> > > >  		 */
> > > >  		if (access(paux, F_OK) < 0) {
> > > >  			if (errno != ENOENT) {
> > > > @@ -1181,7 +1176,11 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
> > > >  			}
> > > >  			pr_info("Created dir %s\n", paux);
> > > >  		} else {
> > > > -			e->properties = NULL;
> > > > +			if (e->n_properties > 0) {
> > > > +				xfree(e->properties);
> > > > +				e->properties = NULL;
> > > > +				e->n_properties = 0;
> > > > +			}
> > > >  			pr_info("Determined dir %s already existed\n", paux);
> > > >  		}
> > > >  
> > > > -- 
> > > > 1.9.1
> > > > 
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