From 130fdbc3d1f9966dd4230709c30f3768bccd3065 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 2 Jun 2020 22:20:25 +0200 Subject: ovl: pass correct flags for opening real directory The three instances of ovl_path_open() in overlayfs/readdir.c do three different things: - pass f_flags from overlay file - pass O_RDONLY | O_DIRECTORY - pass just O_RDONLY The value of f_flags can be (other than O_RDONLY): O_WRONLY - not possible for a directory O_RDWR - not possible for a directory O_CREAT - masked out by dentry_open() O_EXCL - masked out by dentry_open() O_NOCTTY - masked out by dentry_open() O_TRUNC - masked out by dentry_open() O_APPEND - no effect on directory ops O_NDELAY - no effect on directory ops O_NONBLOCK - no effect on directory ops __O_SYNC - no effect on directory ops O_DSYNC - no effect on directory ops FASYNC - no effect on directory ops O_DIRECT - no effect on directory ops O_LARGEFILE - ? O_DIRECTORY - only affects lookup O_NOFOLLOW - only affects lookup O_NOATIME - overlay sets this unconditionally in ovl_path_open() O_CLOEXEC - only affects fd allocation O_PATH - no effect on directory ops __O_TMPFILE - not possible for a directory Fon non-merge directories we use the underlying filesystem's iterate; in this case honor O_LARGEFILE from the original file to make sure that open doesn't get rejected. For merge directories it's safe to pass O_LARGEFILE unconditionally since userspace will only see the artificial offsets created by overlayfs. Signed-off-by: Miklos Szeredi --- fs/overlayfs/readdir.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'fs/overlayfs/readdir.c') diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index a10b21b562ad..3bc97065cc70 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -297,7 +297,7 @@ static inline int ovl_dir_read(struct path *realpath, struct file *realfile; int err; - realfile = ovl_path_open(realpath, O_RDONLY | O_DIRECTORY); + realfile = ovl_path_open(realpath, O_RDONLY | O_LARGEFILE); if (IS_ERR(realfile)) return PTR_ERR(realfile); @@ -831,6 +831,12 @@ out_unlock: return res; } +static struct file *ovl_dir_open_realfile(struct file *file, + struct path *realpath) +{ + return ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE)); +} + static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end, int datasync) { @@ -853,7 +859,7 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end, struct path upperpath; ovl_path_upper(dentry, &upperpath); - realfile = ovl_path_open(&upperpath, O_RDONLY); + realfile = ovl_dir_open_realfile(file, &upperpath); inode_lock(inode); if (!od->upperfile) { @@ -904,7 +910,7 @@ static int ovl_dir_open(struct inode *inode, struct file *file) return -ENOMEM; type = ovl_path_real(file->f_path.dentry, &realpath); - realfile = ovl_path_open(&realpath, file->f_flags); + realfile = ovl_dir_open_realfile(file, &realpath); if (IS_ERR(realfile)) { kfree(od); return PTR_ERR(realfile); -- cgit v1.2.3