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Commit e6bc9de7 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'vfs-5.4-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux 

Pull swap access updates from Darrick Wong:
 "Prohibit writing to active swap files and swap partitions.

  There's no non-malicious use case for allowing userspace to scribble
  on storage that the kernel thinks it owns"

* tag 'vfs-5.4-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  vfs: don't allow writes to swap files
  mm: set S_SWAPFILE on blockdev swap devices
parents b6c0d357 dc617f29

fs/block_dev.c

+3 −0
Original line number Diff line number Diff line
@@ -1972,6 +1972,9 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 
	if (bdev_read_only(I_BDEV(bd_inode)))

		return -EPERM;



	if (IS_SWAPFILE(bd_inode))

		return -ETXTBSY;



	if (!iov_iter_count(from))

		return 0;

include/linux/fs.h

+11 −0
Original line number Diff line number Diff line
@@ -3565,4 +3565,15 @@ static inline void simple_fill_fsxattr(struct fsxattr *fa, __u32 xflags) 
	fa->fsx_xflags = xflags;

}



/*

 * Flush file data before changing attributes.  Caller must hold any locks

 * required to prevent further writes to this file until we're done setting

 * flags.

 */

static inline int inode_drain_writes(struct inode *inode)

{

	inode_dio_wait(inode);

	return filemap_write_and_wait(inode->i_mapping);

}



#endif /* _LINUX_FS_H */

mm/filemap.c

+3 −0
Original line number Diff line number Diff line
@@ -2988,6 +2988,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) 
	loff_t count;

	int ret;



	if (IS_SWAPFILE(inode))

		return -ETXTBSY;



	if (!iov_iter_count(from))

		return 0;

mm/memory.c

+4 −0
Original line number Diff line number Diff line
@@ -2196,6 +2196,10 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) 


	vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;



	if (vmf->vma->vm_file &&

	    IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host))

		return VM_FAULT_SIGBUS;



	ret = vmf->vma->vm_ops->page_mkwrite(vmf);

	/* Restore original flags so that caller is not surprised */

	vmf->flags = old_flags;

mm/mmap.c

+6 −2
Original line number Diff line number Diff line
@@ -1483,8 +1483,12 @@ unsigned long do_mmap(struct file *file, unsigned long addr, 
		case MAP_SHARED_VALIDATE:

			if (flags & ~flags_mask)

				return -EOPNOTSUPP;

			if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))

			if (prot & PROT_WRITE) {

				if (!(file->f_mode & FMODE_WRITE))

					return -EACCES;

				if (IS_SWAPFILE(file->f_mapping->host))

					return -ETXTBSY;

			}



			/*

			 * Make sure we don't allow writing to an append-only