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-rw-r--r--fs/proc/base.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 8f1f49c..a3a3eec 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -534,12 +534,15 @@ static int proc_oom_score(struct task_struct *task, char *buffer)
/* If the process being read is separated by chroot from the reading process,
* don't let the reader access the threads.
+ *
+ * note: this does dput(root) and mntput(vfsmnt) on exit.
*/
static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt)
{
struct dentry *de, *base;
struct vfsmount *our_vfsmnt, *mnt;
int res = 0;
+
read_lock(&current->fs->lock);
our_vfsmnt = mntget(current->fs->rootmnt);
base = dget(current->fs->root);
@@ -549,11 +552,11 @@ static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt)
de = root;
mnt = vfsmnt;
- while (vfsmnt != our_vfsmnt) {
- if (vfsmnt == vfsmnt->mnt_parent)
+ while (mnt != our_vfsmnt) {
+ if (mnt == mnt->mnt_parent)
goto out;
- de = vfsmnt->mnt_mountpoint;
- vfsmnt = vfsmnt->mnt_parent;
+ de = mnt->mnt_mountpoint;
+ mnt = mnt->mnt_parent;
}
if (!is_subdir(de, base))
@@ -564,7 +567,7 @@ exit:
dput(base);
mntput(our_vfsmnt);
dput(root);
- mntput(mnt);
+ mntput(vfsmnt);
return res;
out:
spin_unlock(&vfsmount_lock);
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