Messages in this thread | | | Date | Fri, 19 May 2006 14:46:31 -0400 | From | Chuck Lever <> | Subject | Re: [PATCH 5/6] nfs: check all iov segments for correct memory access rights |
| |
Andrew Morton wrote: > Chuck Lever <cel@netapp.com> wrote: >> +static ssize_t check_access_ok(int type, const struct iovec *iov, unsigned long nr_segs) >> +{ >> + ssize_t count = 0; >> + ssize_t retval = -EINVAL; >> + unsigned long seg; >> + >> + for (seg = 0; seg < nr_segs; seg++) { >> + void __user *buf = iov[seg].iov_base; >> + ssize_t len = (ssize_t) iov[seg].iov_len; >> + >> + if (len < 0) /* size_t not fitting an ssize_t .. */ >> + goto out; > > do_readv_writev() already checked for negative iov_len, and that's the more > appropriate place to do it, rather than duplicating it in each filesystem > (or forgetting to!) > > So is this check really needed?
Ok, didn't see that function before. Badari, is this checking still needed?
>> + if (unlikely(!access_ok(type, buf, len))) { >> + retval = -EFAULT; >> + goto out; >> + } > > Now what's up here? Why does NFS, at this level, care about the page's > virtual address? get_user_pages() will handle that?
Interesting point. That may be a historical artifact that can be removed. I'll take a look.
-- corporate: cel at netapp dot com personal: chucklever at bigfoot dot com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |