On Wed, Jul 22, 2009 at 9:13 AM, Jeff Layton<jlayton@xxxxxxxxxx> wrote: > On Wed, 2009-07-22 at 15:51 +0200, Johannes Weiner wrote: > >> > Any of these patches will fix the immediate problem, but I think this >> > code in do_sendfile should still account for the possibility that >> > someone can set the value larger than MAX_LFS_FILESIZE. An alternative >> > is to consider a WARN at mount time when filesystems set s_maxbytes >> > larger than that value (that might help catch out of tree filesystems >> > that get this wrong and prevent this sort of silent bug in the future). >> >> Isn't MAX_LFS_FILESIZE by definition the maximum sensible value for >> s_maxbytes? >> > > Pretty much, but nothing seems to enforce it or let you know when you've > exceeded it. It sort of seems like s_maxbytes ought to be loff_t or > something instead of an unsigned long long. A negative value there > wouldn't make much sense, but no one would be as tempted to set it > higher than MAX_LFS_FILESIZE. > >> > Either way, the patch I posted for this isn't sufficient since there are >> > some checks that need to be done against the signed values (the >> > (pos < 0) check, for instance). I'll post a respun patch in a bit that >> > should fix up those problems. >> >> That is already handled in rw_verify_area(), I think, so we should be >> able to drop it completely. > > If we get rid of those checks altogether, then "max" will become unused. > Is that really OK here? > > For discussion purposes, I've attached a replacement patch that I'm > working with now. Looks fine to me -- Thanks, Steve -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
