hibernate: Allow uswsusp to write to swap

[ Upstream commit 56939e014a6c212b317414faa307029e2e80c3b9 ]

It turns out that there is one use case for programs being able to
write to swap devices, and that is the userspace hibernation code.

Quick fix: disable the S_SWAPFILE check if hibernation is configured.

Fixes: dc617f29db ("vfs: don't allow writes to swap files")
Reported-by: Domenico Andreoli <domenico.andreoli@linux.com>
Reported-by: Marian Klein <mkleinsoft@gmail.com>
Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Domenico Andreoli 2020-03-23 08:22:15 -07:00 committed by Greg Kroah-Hartman
parent 4753b111f0
commit 285f25c97f
1 changed files with 3 additions and 1 deletions

View File

@ -34,6 +34,7 @@
#include <linux/task_io_accounting_ops.h>
#include <linux/falloc.h>
#include <linux/uaccess.h>
#include <linux/suspend.h>
#include "internal.h"
struct bdev_inode {
@ -1975,7 +1976,8 @@ 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))
/* uswsusp needs write permission to the swap */
if (IS_SWAPFILE(bd_inode) && !hibernation_available())
return -ETXTBSY;
if (!iov_iter_count(from))