Date: Wed, 24 Feb 2016 23:41:40 -0800 From: Adrian Chadd <adrian.chadd@gmail.com> To: Kristof Provost <kp@freebsd.org> Cc: "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r296025 - head/sys/netpfil/pf Message-ID: <CAJ-Vmok_-SzGnUdYi%2BnnDYdGhcKXOUthC1nnPyxHrnWJCKA%2Bcw@mail.gmail.com> In-Reply-To: <201602250733.u1P7Xxoh041746@repo.freebsd.org> References: <201602250733.u1P7Xxoh041746@repo.freebsd.org>
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.. what's capping totlen so one doesn't run out of memory? -a On 24 February 2016 at 23:33, Kristof Provost <kp@freebsd.org> wrote: > Author: kp > Date: Thu Feb 25 07:33:59 2016 > New Revision: 296025 > URL: https://svnweb.freebsd.org/changeset/base/296025 > > Log: > pf: Fix possible out-of-bounds write > > In the DIOCRSETADDRS ioctl() handler we allocate a table for struct pfr_addrs, > which is processed in pfr_set_addrs(). At the users request we also provide > feedback on the deleted addresses, by storing them after the new list > ('bcopy(&ad, addr + size + i, sizeof(ad));' in pfr_set_addrs()). > > This means we write outside the bounds of the buffer we've just allocated. > We need to look at pfrio_size2 instead (i.e. the size the user reserved for our > feedback). That'd allow a malicious user to specify a smaller pfrio_size2 than > pfrio_size though, in which case we'd still read outside of the allocated > buffer. Instead we allocate the largest of the two values. > > Reported By: Paul J Murphy <paul@inetstat.net> > PR: 207463 > MFC after: 5 days > Differential Revision: https://reviews.freebsd.org/D5426 > > Modified: > head/sys/netpfil/pf/pf_ioctl.c > > Modified: head/sys/netpfil/pf/pf_ioctl.c > ============================================================================== > --- head/sys/netpfil/pf/pf_ioctl.c Thu Feb 25 07:03:10 2016 (r296024) > +++ head/sys/netpfil/pf/pf_ioctl.c Thu Feb 25 07:33:59 2016 (r296025) > @@ -2718,13 +2718,14 @@ DIOCCHANGEADDR_error: > case DIOCRSETADDRS: { > struct pfioc_table *io = (struct pfioc_table *)addr; > struct pfr_addr *pfras; > - size_t totlen; > + size_t totlen, count; > > if (io->pfrio_esize != sizeof(struct pfr_addr)) { > error = ENODEV; > break; > } > - totlen = io->pfrio_size * sizeof(struct pfr_addr); > + count = max(io->pfrio_size, io->pfrio_size2); > + totlen = count * sizeof(struct pfr_addr); > pfras = malloc(totlen, M_TEMP, M_WAITOK); > error = copyin(io->pfrio_buffer, pfras, totlen); > if (error) { >
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