Messages in this thread | | | Date | Wed, 19 Nov 2008 14:00:55 +0530 | From | Balbir Singh <> | Subject | Re: [PATCH] cgroups: fix a serious bug in cgroupstats |
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Andrew Morton wrote: > On Wed, 19 Nov 2008 16:14:41 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote: > >> Try this, and you'll get oops immediately: > > I guess that's wrong. > >> # cd Documentation/accounting/ >> # gcc -o getdelays getdelays.c >> # mount -t cgroup -o debug xxx /mnt >> # ./getdelays -C /mnt/tasks >> >> Because a normal file's dentry->d_fsdata is a pointer to struct cftype, >> not struct cgroup. >> >> After the patch, it returns EINVAL if we try to get cgroupstats >> from a normal file. >> >> CC: Balbir Singh <balbir@linux.vnet.ibm.com> >> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> >> --- >> kernel/cgroup.c | 7 +++++-- >> 1 files changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/cgroup.c b/kernel/cgroup.c >> index 358e775..f6f5219 100644 >> --- a/kernel/cgroup.c >> +++ b/kernel/cgroup.c >> @@ -2039,10 +2039,13 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) >> struct cgroup *cgrp; >> struct cgroup_iter it; >> struct task_struct *tsk; >> + >> /* >> - * Validate dentry by checking the superblock operations >> + * Validate dentry by checking the superblock operations, >> + * and make sure it's a directory. >> */ >> - if (dentry->d_sb->s_op != &cgroup_ops) >> + if (dentry->d_sb->s_op != &cgroup_ops || >> + !S_ISDIR(dentry->d_inode->i_mode)) >> goto err; >> >> ret = 0; > > The patch applies OK to 2.6.25, 2.6.26 and to 2.6.27. I marked it as > needing backport to those kernel versions. Please let me know if that > was inappropriate. >
Thanks, it does need to be backported. Thanks Li for spotting the problem.
-- Balbir
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