This is a note to let you know that I've just added the patch titled
btrfs: fix fallocate to use file_modified to update permissions consistently
to the 5.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-fix-fallocate-to-use-file_modified-to-update-p.patch
and it can be found in the queue-5.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 10cd52db25b140847516d2246a9ecf640e0fcb87
Author: Darrick J. Wong <djwong@xxxxxxxxxx>
Date: Mon Mar 14 10:55:32 2022 -0700
btrfs: fix fallocate to use file_modified to update permissions consistently
[ Upstream commit 05fd9564e9faf0f23b4676385e27d9405cef6637 ]
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 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.
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a0179cc62913..28ddd9cf2069 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2918,8 +2918,9 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode,
return ret;
}
-static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
+static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len)
{
+ struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_state *cached_state = NULL;
@@ -2951,6 +2952,10 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
goto out_only_mutex;
}
+ ret = file_modified(file);
+ if (ret)
+ goto out_only_mutex;
+
lockstart = round_up(offset, btrfs_inode_sectorsize(BTRFS_I(inode)));
lockend = round_down(offset + len,
btrfs_inode_sectorsize(BTRFS_I(inode))) - 1;
@@ -3391,7 +3396,7 @@ static long btrfs_fallocate(struct file *file, int mode,
return -EOPNOTSUPP;
if (mode & FALLOC_FL_PUNCH_HOLE)
- return btrfs_punch_hole(inode, offset, len);
+ return btrfs_punch_hole(file, offset, len);
/*
* Only trigger disk allocation, don't trigger qgroup reserve
@@ -3413,6 +3418,10 @@ static long btrfs_fallocate(struct file *file, int mode,
goto out;
}
+ ret = file_modified(file);
+ if (ret)
+ goto out;
+
/*
* TODO: Move these two operations after we have checked
* accurate reserved space, or fallocate can still fail but
