From 983d8e60f50806f90534cc5373d0ce867e5aaf79 Mon Sep 17 00:00:00 2001

From: "Darrick J. Wong" <djwong@kernel.org>

Date: Wed, 22 Dec 2021 14:19:18 -0800

Subject: [PATCH] xfs: map unwritten blocks in XFS_IOC_{ALLOC,FREE}SP just like

 fallocate

Git-commit: 983d8e60f50806f90534cc5373d0ce867e5aaf79

Patch-mainline: v5.16

References: bsc#1194272 CVE-2021-4155

The old ALLOCSP/FREESP ioctls in XFS can be used to preallocate space at

the end of files, just like fallocate and RESVSP.  Make the behavior

consistent with the other ioctls.

Reported-by: Kirill Tkhai <ktkhai@virtuozzo.com>

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Reviewed-by: Dave Chinner <dchinner@redhat.com>

Reviewed-by: Eric Sandeen <sandeen@redhat.com>

Acked-by: Anthony Iliopoulos <ailiop@suse.com>

---

 fs/xfs/xfs_ioctl.c | 3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c

index 174cd8950cb6..bc85e045845d 100644

--- a/fs/xfs/xfs_ioctl.c

+++ b/fs/xfs/xfs_ioctl.c

@@ -687,7 +687,8 @@ xfs_ioc_space(

 	if (bf->l_start > XFS_ISIZE(ip)) {

 		error = xfs_alloc_file_space(ip, XFS_ISIZE(ip),

-				bf->l_start - XFS_ISIZE(ip), 0);

+				bf->l_start - XFS_ISIZE(ip),

+				XFS_BMAPI_PREALLOC);

 		if (error)

 			goto out_unlock;

 	}

--

2.31.1