From: Li Zefan Date: Wed, 19 Nov 2008 23:36:48 +0000 (-0800) Subject: cgroups: fix a serious bug in cgroupstats X-Git-Tag: v2.6.28-rc6~18 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=33d283bef23132c48195eafc21449f8ba88fce6b;p=linux-2.6-omap-h63xx.git cgroups: fix a serious bug in cgroupstats 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 Signed-off-by: Li Zefan Acked-by: Paul Menage Cc: [2.6.25.x, 2.6.26.x, 2.6.27.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 1a06be61dcd..fe00b3b983a 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;