From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org,
linux-mm@kvack.org
Subject: [PATCH 7/8] btrfs: don't allow any modifications to an immutable file
Date: Wed, 17 Apr 2019 12:05:13 -0700 [thread overview]
Message-ID: <155552791345.20411.13373076079148473736.stgit@magnolia> (raw)
In-Reply-To: <155552786671.20411.6442426840435740050.stgit@magnolia>
From: Darrick J. Wong <darrick.wong@oracle.com>
Don't allow any modifications to a file that's marked immutable, which
means that we have to flush all the writable pages to make the readonly
and we have to check the setattr/setflags parameters more closely.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/btrfs/ioctl.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index cd4e693406a0..632600e4be0a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -180,6 +180,44 @@ static int check_fsflags(unsigned int flags)
return 0;
}
+/* Do all the prep work to check immutable status and all that. */
+static int btrfs_ioctl_check_immutable(struct inode *inode,
+ unsigned int fsflags,
+ const unsigned int immutable_fsflag)
+{
+ struct btrfs_inode *binode = BTRFS_I(inode);
+ int ret;
+
+ /*
+ * Wait for all pending directio and then flush all the dirty pages
+ * for this file. The flush marks all the pages readonly, so any
+ * subsequent attempt to write to the file (particularly mmap pages)
+ * will come through the filesystem and fail.
+ */
+ if (S_ISREG(inode->i_mode) && !IS_IMMUTABLE(inode) &&
+ (fsflags & immutable_fsflag)) {
+ inode_dio_wait(inode);
+ ret = filemap_write_and_wait(inode->i_mapping);
+ if (ret)
+ return ret;
+ }
+
+ /*
+ * If immutable is set and we are not clearing it, we're not allowed to
+ * change anything else in the inode. Don't error out if we're only
+ * trying to set immutable on an immutable file.
+ */
+ if (!(binode->flags & BTRFS_INODE_IMMUTABLE) ||
+ !(fsflags & immutable_fsflag))
+ return 0;
+
+ if ((binode->flags & ~BTRFS_INODE_IMMUTABLE) !=
+ (fsflags & ~immutable_fsflag))
+ return -EPERM;
+
+ return 0;
+}
+
static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
{
struct inode *inode = file_inode(file);
@@ -225,6 +263,10 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
}
}
+ ret = btrfs_ioctl_check_immutable(inode, fsflags, FS_IMMUTABLE_FL);
+ if (ret)
+ goto out_unlock;
+
if (fsflags & FS_SYNC_FL)
binode->flags |= BTRFS_INODE_SYNC;
else
@@ -433,6 +475,11 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
goto out_unlock;
}
+ ret = btrfs_ioctl_check_immutable(inode, fa.fsx_xflags,
+ FS_XFLAG_IMMUTABLE);
+ if (ret)
+ goto out_unlock;
+
if (fa.fsx_xflags & FS_XFLAG_SYNC)
binode->flags |= BTRFS_INODE_SYNC;
else
next prev parent reply other threads:[~2019-04-17 19:05 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-17 19:04 [PATCH v2 0/8] vfs: make immutable files actually immutable Darrick J. Wong
2019-04-17 19:04 ` [PATCH 1/8] mm/fs: don't allow writes to immutable files Darrick J. Wong
2019-04-26 18:17 ` Brian Foster
2019-06-10 1:43 ` Theodore Ts'o
2019-06-10 1:51 ` Theodore Ts'o
2019-06-10 4:41 ` Darrick J. Wong
2019-06-10 13:14 ` Theodore Ts'o
2019-06-10 16:09 ` Darrick J. Wong
2019-06-10 20:41 ` Theodore Ts'o
2019-06-11 3:26 ` Darrick J. Wong
2019-06-11 4:01 ` Darrick J. Wong
2019-04-17 19:04 ` [PATCH 2/8] xfs: unlock inode when xfs_ioctl_setattr_get_trans can't get transaction Darrick J. Wong
2019-04-26 18:17 ` Brian Foster
2019-04-17 19:04 ` [PATCH 3/8] xfs: flush page mappings as part of setting immutable Darrick J. Wong
2019-04-26 18:18 ` Brian Foster
2019-04-17 19:04 ` [PATCH 4/8] xfs: refactor setflags to use setattr code directly Darrick J. Wong
2019-04-17 19:05 ` [PATCH 5/8] xfs: clean up xfs_merge_ioc_xflags Darrick J. Wong
2019-04-17 19:05 ` [PATCH 6/8] xfs: don't allow most setxattr to immutable files Darrick J. Wong
2019-04-17 19:05 ` Darrick J. Wong [this message]
2019-04-17 19:05 ` [PATCH 8/8] ext4: don't allow any modifications to an immutable file Darrick J. Wong
2019-04-30 15:46 ` [PATCH v2 0/8] vfs: make immutable files actually immutable David Sterba
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