Messages in this thread Patch in this message | | | Date | Wed, 3 Dec 2008 11:48:31 -0800 | From | Greg KH <> | Subject | [patch 008/104] cgroups: fix a serious bug in cgroupstats |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------ From: Li Zefan <lizf@cn.fujitsu.com>
commit 33d283bef23132c48195eafc21449f8ba88fce6b upstream.
Try this, and you'll get oops immediately: # 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> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/cgroup.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2045,10 +2045,13 @@ int cgroupstats_build(struct cgroupstats 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;
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