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pf: Fix possible out-of-bounds write

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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
This commit is contained in:
Kristof Provost 2016-02-25 07:33:59 +00:00
parent fd458696b3
commit 14b5e85b18
1 changed files with 3 additions and 2 deletions
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5
sys/netpfil/pf/pf_ioctl.c
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@ -2718,13 +2718,14 @@ pfioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread *td
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) {