On Wed, Jun 09, 2021 at 10:17:19AM +0300, Alexander Kuznetsov wrote: > cgroup_mkdir() have restriction on newline usage in names: > $ mkdir $'/sys/fs/cgroup/cpu/test\ntest2' > mkdir: cannot create directory > '/sys/fs/cgroup/cpu/test\ntest2': Invalid argument > > But in cgroup1_rename() such check is missed. > This allows us to make /proc/<pid>/cgroup unparsable: > $ mkdir /sys/fs/cgroup/cpu/test > $ mv /sys/fs/cgroup/cpu/test $'/sys/fs/cgroup/cpu/test\ntest2' > $ echo $$ > $'/sys/fs/cgroup/cpu/test\ntest2' > $ cat /proc/self/cgroup > 11:pids:/ > 10:freezer:/ > 9:hugetlb:/ > 8:cpuset:/ > 7:blkio:/user.slice > 6:memory:/user.slice > 5:net_cls,net_prio:/ > 4:perf_event:/ > 3:devices:/user.slice > 2:cpu,cpuacct:/test > test2 > 1:name=systemd:/ > 0::/ > > Signed-off-by: Alexander Kuznetsov <wwfq@xxxxxxxxxxxxxx> > Reported-by: Andrey Krasichkov <buglloc@xxxxxxxxxxxxxx> > Acked-by: Dmitry Yakunin <zeil@xxxxxxxxxxxxxx> Applied to cgroup/for-5.13-fixes Thanks. -- tejun
