On Fri 22-11-24 13:29:25, Christoph Hellwig wrote: > F_SET_RW_HINT controls the placement of written file data. A read-only > fd should not allow for that. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> Here I'm not so sure. Firstly, since you are an owner this doesn't add any additional practical restriction. Secondly, you are not changing anything on disk, just IO hints in memory... Thirdly, we generally don't require writeable fd even to do file attribute changes (like with fchmod, fchown, etc.). So although the check makes some sense, it seems to be mostly inconsistent with how we treat similar stuff. Honza > --- > fs/fcntl.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/fcntl.c b/fs/fcntl.c > index 7fc6190da342..12f60c42743a 100644 > --- a/fs/fcntl.c > +++ b/fs/fcntl.c > @@ -377,6 +377,8 @@ static long fcntl_set_rw_hint(struct file *file, unsigned int cmd, > > if (!inode_owner_or_capable(file_mnt_idmap(file), inode)) > return -EPERM; > + if (!(file->f_mode & FMODE_WRITE)) > + return -EBADF; > > if (copy_from_user(&hint, argp, sizeof(hint))) > return -EFAULT; > -- > 2.45.2 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
