From 59f42b4150022f216a4e92bbf672ef2bc9c413c8 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Tue, 17 May 2022 11:37:23 +0800 Subject: [PATCH] f2fs: fix fallocate to use file_modified to update permissions consistently commit 958ed92922028ec67f504dcdc72bfdfd0f43936a upstream. This patch tries to fix permission consistency issue as all other mainline filesystems. Since the initial introduction of (posix) fallocate back at the turn of the century, it has been possible to use this syscall to change the user-visible contents of files. This can happen by extending the file size during a preallocation, or through any of the newer modes (punch, zero, collapse, insert range). Because the call can be used to change file contents, we should treat it like we do any other modification to a file -- update the mtime, and drop set[ug]id privileges/capabilities. The VFS function file_modified() does all this for us if pass it a locked inode, so let's make fallocate drop permissions correctly. Cc: stable@kernel.org Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/file.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 9119950..c67756a 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1768,6 +1768,10 @@ static long f2fs_fallocate(struct file *file, int mode, inode_lock(inode); + ret = file_modified(file); + if (ret) + goto out; + if (mode & FALLOC_FL_PUNCH_HOLE) { if (offset >= inode->i_size) goto out; -- 2.7.4