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Commit e4e5d3fc authored by Herbert Poetzl's avatar Herbert Poetzl Committed by Linus Torvalds
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[PATCH] cleanup in proc_check_chroot() 



proc_check_chroot() does the check in a very unintuitive way (keeping a
copy of the argument, then modifying the argument), and has uncommented
sideeffects.

Signed-off-by: default avatarHerbert Poetzl <herbert@13thfloor.at>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 158d9ebd

fs/proc/base.c

+8 −5
Original line number Original line Diff line number Diff line
@@ -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,

/* If the process being read is separated by chroot from the reading process,

 * don't let the reader access the threads.

 * 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)

static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt)

{

{

	struct dentry *de, *base;

	struct dentry *de, *base;

	struct vfsmount *our_vfsmnt, *mnt;

	struct vfsmount *our_vfsmnt, *mnt;

	int res = 0;

	int res = 0;



	read_lock(&current->fs->lock);

	read_lock(&current->fs->lock);

	our_vfsmnt = mntget(current->fs->rootmnt);

	our_vfsmnt = mntget(current->fs->rootmnt);

	base = dget(current->fs->root);

	base = dget(current->fs->root);
@@ -549,11 +552,11 @@ static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt) 
	de = root;

	de = root;

	mnt = vfsmnt;

	mnt = vfsmnt;





	while (vfsmnt != our_vfsmnt) {

	while (mnt != our_vfsmnt) {

		if (vfsmnt == vfsmnt->mnt_parent)

		if (mnt == mnt->mnt_parent)

			goto out;

			goto out;

		de = vfsmnt->mnt_mountpoint;

		de = mnt->mnt_mountpoint;

		vfsmnt = vfsmnt->mnt_parent;

		mnt = mnt->mnt_parent;

	}

	}





	if (!is_subdir(de, base))

	if (!is_subdir(de, base))
@@ -564,7 +567,7 @@ static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt) 
	dput(base);

	dput(base);

	mntput(our_vfsmnt);

	mntput(our_vfsmnt);

	dput(root);

	dput(root);

	mntput(mnt);

	mntput(vfsmnt);

	return res;

	return res;

out:

out:

	spin_unlock(&vfsmount_lock);

	spin_unlock(&vfsmount_lock);