On Sat, 2005-08-20 at 10:30 -0700, Linus Torvalds wrote: > > On Sat, 20 Aug 2005, Miklos Szeredi wrote: > > > > My question is: is this deliberate or accidental? Wouldn't it be more > > logical to not require any permission to open such file? Or is there > > some security concern with that? > > It's deliberate but historical. It's been a long time since I worked on > it, but it was meant for "special opens". > > I _think_ it was used for things like "open block device without media > check" etc (we use O_NONBLOCK for that now), and it was used for directory > opens before we had O_DIRECTORY. (It's literally been years, so my > recollection may be bogus). > > I don't think anything uses it any more, and it should probably be > deprecated rather than extended upon.
It may also be dangerous, since I see several drivers using if ((filp->f_flags & O_ACCMODE) != RD_ONLY) { /* do something assuming we have write access */ ... } Perhaps that access mode may not allow for getting to code like this, but, since it's so old, you may have those that forget about the 3 mode, and we lose the protection somewhere along the line. It probably be better to not allow for it. Or maybe an audit of such code needs to be replaced with: if (filp->f_mode & FMODE_WRITE) { ... } Just my $0.02 -- Steve - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/