Commit 7e9890a3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'ovl-update-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 

Pull overlayfs update from Miklos Szeredi:
 "Just bug fixes in this small update"

* tag 'ovl-update-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: relax WARN_ON() for overlapping layers use case
  ovl: check the capability before cred overridden
  ovl: do not generate duplicate fsnotify events for "fake" path
  ovl: support stacked SEEK_HOLE/SEEK_DATA
  ovl: fix missing upper fs freeze protection on copy up for ioctl
parents 4856118f acf3062a

fs/overlayfs/copy_up.c

+3 −3
Original line number Diff line number Diff line
@@ -909,14 +909,14 @@ static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) 
	return true;

}



int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)

int ovl_maybe_copy_up(struct dentry *dentry, int flags)

{

	int err = 0;



	if (ovl_open_need_copy_up(dentry, file_flags)) {

	if (ovl_open_need_copy_up(dentry, flags)) {

		err = ovl_want_write(dentry);

		if (!err) {

			err = ovl_copy_up_flags(dentry, file_flags);

			err = ovl_copy_up_flags(dentry, flags);

			ovl_drop_write(dentry);

		}

	}

fs/overlayfs/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -260,7 +260,7 @@ static int ovl_instantiate(struct dentry *dentry, struct inode *inode, 
		 * hashed directory inode aliases.

		 */

		inode = ovl_get_inode(dentry->d_sb, &oip);

		if (WARN_ON(IS_ERR(inode)))

		if (IS_ERR(inode))

			return PTR_ERR(inode);

	} else {

		WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));

fs/overlayfs/file.c

+106 −27
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/mount.h>

#include <linux/xattr.h>

#include <linux/uio.h>

#include <linux/uaccess.h>

#include "overlayfs.h"



static char ovl_whatisit(struct inode *inode, struct inode *realinode)
@@ -29,10 +30,11 @@ static struct file *ovl_open_realfile(const struct file *file, 
	struct inode *inode = file_inode(file);

	struct file *realfile;

	const struct cred *old_cred;

	int flags = file->f_flags | O_NOATIME | FMODE_NONOTIFY;



	old_cred = ovl_override_creds(inode->i_sb);

	realfile = open_with_fake_path(&file->f_path, file->f_flags | O_NOATIME,

				       realinode, current_cred());

	realfile = open_with_fake_path(&file->f_path, flags, realinode,

				       current_cred());

	revert_creds(old_cred);



	pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
@@ -50,7 +52,7 @@ static int ovl_change_flags(struct file *file, unsigned int flags) 
	int err;



	/* No atime modificaton on underlying */

	flags |= O_NOATIME;

	flags |= O_NOATIME | FMODE_NONOTIFY;



	/* If some flag changed that cannot be changed then something's amiss */

	if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))
@@ -116,11 +118,10 @@ static int ovl_real_fdget(const struct file *file, struct fd *real) 


static int ovl_open(struct inode *inode, struct file *file)

{

	struct dentry *dentry = file_dentry(file);

	struct file *realfile;

	int err;



	err = ovl_open_maybe_copy_up(dentry, file->f_flags);

	err = ovl_maybe_copy_up(file_dentry(file), file->f_flags);

	if (err)

		return err;
@@ -145,11 +146,47 @@ static int ovl_release(struct inode *inode, struct file *file) 


static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)

{

	struct inode *realinode = ovl_inode_real(file_inode(file));

	struct inode *inode = file_inode(file);

	struct fd real;

	const struct cred *old_cred;

	ssize_t ret;



	return generic_file_llseek_size(file, offset, whence,

					realinode->i_sb->s_maxbytes,

					i_size_read(realinode));

	/*

	 * The two special cases below do not need to involve real fs,

	 * so we can optimizing concurrent callers.

	 */

	if (offset == 0) {

		if (whence == SEEK_CUR)

			return file->f_pos;



		if (whence == SEEK_SET)

			return vfs_setpos(file, 0, 0);

	}



	ret = ovl_real_fdget(file, &real);

	if (ret)

		return ret;



	/*

	 * Overlay file f_pos is the master copy that is preserved

	 * through copy up and modified on read/write, but only real

	 * fs knows how to SEEK_HOLE/SEEK_DATA and real fs may impose

	 * limitations that are more strict than ->s_maxbytes for specific

	 * files, so we use the real file to perform seeks.

	 */

	inode_lock(inode);

	real.file->f_pos = file->f_pos;



	old_cred = ovl_override_creds(inode->i_sb);

	ret = vfs_llseek(real.file, offset, whence);

	revert_creds(old_cred);



	file->f_pos = real.file->f_pos;

	inode_unlock(inode);



	fdput(real);



	return ret;

}



static void ovl_file_accessed(struct file *file)
@@ -372,34 +409,76 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd, 
	return ret;

}



static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

static unsigned int ovl_get_inode_flags(struct inode *inode)

{

	unsigned int flags = READ_ONCE(inode->i_flags);

	unsigned int ovl_iflags = 0;



	if (flags & S_SYNC)

		ovl_iflags |= FS_SYNC_FL;

	if (flags & S_APPEND)

		ovl_iflags |= FS_APPEND_FL;

	if (flags & S_IMMUTABLE)

		ovl_iflags |= FS_IMMUTABLE_FL;

	if (flags & S_NOATIME)

		ovl_iflags |= FS_NOATIME_FL;



	return ovl_iflags;

}



static long ovl_ioctl_set_flags(struct file *file, unsigned long arg)

{

	long ret;

	struct inode *inode = file_inode(file);

	unsigned int flags;

	unsigned int old_flags;



	switch (cmd) {

	case FS_IOC_GETFLAGS:

		ret = ovl_real_ioctl(file, cmd, arg);

		break;



	case FS_IOC_SETFLAGS:

	if (!inode_owner_or_capable(inode))

		return -EACCES;



	if (get_user(flags, (int __user *) arg))

		return -EFAULT;



	ret = mnt_want_write_file(file);

	if (ret)

		return ret;



		ret = ovl_copy_up_with_data(file_dentry(file));

		if (!ret) {

			ret = ovl_real_ioctl(file, cmd, arg);



	inode_lock(inode);



	/* Check the capability before cred override */

	ret = -EPERM;

	old_flags = ovl_get_inode_flags(inode);

	if (((flags ^ old_flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) &&

	    !capable(CAP_LINUX_IMMUTABLE))

		goto unlock;



	ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);

	if (ret)

		goto unlock;



	ret = ovl_real_ioctl(file, FS_IOC_SETFLAGS, arg);



	ovl_copyflags(ovl_inode_real(inode), inode);

unlock:

	inode_unlock(inode);

		}



	mnt_drop_write_file(file);



	return ret;



}



static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	long ret;



	switch (cmd) {

	case FS_IOC_GETFLAGS:

		ret = ovl_real_ioctl(file, cmd, arg);

		break;



	case FS_IOC_SETFLAGS:

		ret = ovl_ioctl_set_flags(file, arg);

		break;



	default:

fs/overlayfs/inode.c

+2 −1
Original line number Diff line number Diff line
@@ -832,7 +832,7 @@ struct inode *ovl_get_inode(struct super_block *sb, 
	int fsid = bylower ? oip->lowerpath->layer->fsid : 0;

	bool is_dir, metacopy = false;

	unsigned long ino = 0;

	int err = -ENOMEM;

	int err = oip->newinode ? -EEXIST : -ENOMEM;



	if (!realinode)

		realinode = d_inode(lowerdentry);
@@ -917,6 +917,7 @@ out: 
	return inode;



out_err:

	pr_warn_ratelimited("overlayfs: failed to get inode (%i)\n", err);

	inode = ERR_PTR(err);

	goto out;

}

fs/overlayfs/overlayfs.h

+1 −1
Original line number Diff line number Diff line
@@ -421,7 +421,7 @@ extern const struct file_operations ovl_file_operations; 
int ovl_copy_up(struct dentry *dentry);

int ovl_copy_up_with_data(struct dentry *dentry);

int ovl_copy_up_flags(struct dentry *dentry, int flags);

int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);

int ovl_maybe_copy_up(struct dentry *dentry, int flags);

int ovl_copy_xattr(struct dentry *old, struct dentry *new);

int ovl_set_attr(struct dentry *upper, struct kstat *stat);

struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);

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