From 3428030da004a1128cbdcf93dc03e16f184d845b Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Tue, 22 Jan 2019 07:01:39 +0200 Subject: ovl: fix missing upper fs freeze protection on copy up for ioctl Generalize the helper ovl_open_maybe_copy_up() and use it to copy up file with data before FS_IOC_SETFLAGS ioctl. The FS_IOC_SETFLAGS ioctl is a bit of an odd ball in vfs, which probably caused the confusion. File may be open O_RDONLY, but ioctl modifies the file. VFS does not call mnt_want_write_file() nor lock inode mutex, but fs-specific code for FS_IOC_SETFLAGS does. So ovl_ioctl() calls mnt_want_write_file() for the overlay file, and fs-specific code calls mnt_want_write_file() for upper fs file, but there was no call for ovl_want_write() for copy up duration which prevents overlayfs from copying up on a frozen upper fs. Fixes: dab5ca8fd9dd ("ovl: add lsattr/chattr support") Cc: # v4.19 Signed-off-by: Amir Goldstein Acked-by: Vivek Goyal Signed-off-by: Miklos Szeredi --- fs/overlayfs/copy_up.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/overlayfs/copy_up.c') diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 68b3303e4b46..56feaa739979 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -909,14 +909,14 @@ static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) return true; } -int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) +int ovl_maybe_copy_up(struct dentry *dentry, int flags) { int err = 0; - if (ovl_open_need_copy_up(dentry, file_flags)) { + if (ovl_open_need_copy_up(dentry, flags)) { err = ovl_want_write(dentry); if (!err) { - err = ovl_copy_up_flags(dentry, file_flags); + err = ovl_copy_up_flags(dentry, flags); ovl_drop_write(dentry); } } -- cgit v1.2.3