From adfe2f6aff00c658f9f2d4b29cc006e058570dcf Mon Sep 17 00:00:00 2001 From: Kristof Provost Date: Fri, 6 Apr 2018 15:54:30 +0000 Subject: [PATCH] pf: Improve ioctl validation for DIOCRGETTABLES, DIOCRGETTSTATS, DIOCRCLRTSTATS and DIOCRSETTFLAGS These ioctls can process a number of items at a time, which puts us at risk of overflow in mallocarray() and of impossibly large allocations even if we don't overflow. Limit the allocation to required size (or the user allocation, if that's smaller). That does mean we need to do the allocation with the rules lock held (so the number doesn't change while we're doing this), so it can't M_WAITOK. MFC after: 1 week --- sys/net/pfvar.h | 1 + sys/netpfil/pf/pf_ioctl.c | 53 +++++++++++++++++++++++++++------------ sys/netpfil/pf/pf_table.c | 3 +-- 3 files changed, 39 insertions(+), 18 deletions(-) diff --git a/sys/net/pfvar.h b/sys/net/pfvar.h index dfff0b87445f..1409318c2f47 100644 --- a/sys/net/pfvar.h +++ b/sys/net/pfvar.h @@ -1638,6 +1638,7 @@ void pfr_detach_table(struct pfr_ktable *); int pfr_clr_tables(struct pfr_table *, int *, int); int pfr_add_tables(struct pfr_table *, int, int *, int); int pfr_del_tables(struct pfr_table *, int, int *, int); +int pfr_table_count(struct pfr_table *, int); int pfr_get_tables(struct pfr_table *, struct pfr_table *, int *, int); int pfr_get_tstats(struct pfr_table *, struct pfr_tstats *, int *, int); int pfr_clr_tstats(struct pfr_table *, int, int *, int); diff --git a/sys/netpfil/pf/pf_ioctl.c b/sys/netpfil/pf/pf_ioctl.c index a0d1ca4a5b3b..d63b83000661 100644 --- a/sys/netpfil/pf/pf_ioctl.c +++ b/sys/netpfil/pf/pf_ioctl.c @@ -2588,20 +2588,25 @@ DIOCCHANGEADDR_error: case DIOCRGETTABLES: { struct pfioc_table *io = (struct pfioc_table *)addr; struct pfr_table *pfrts; - size_t totlen; + size_t totlen, n; if (io->pfrio_esize != sizeof(struct pfr_table)) { error = ENODEV; break; } + PF_RULES_RLOCK(); + n = pfr_table_count(&io->pfrio_table, io->pfrio_flags); + io->pfrio_size = min(io->pfrio_size, n); + totlen = io->pfrio_size * sizeof(struct pfr_table); + pfrts = mallocarray(io->pfrio_size, sizeof(struct pfr_table), - M_TEMP, M_WAITOK); - if (! pfrts) { + M_TEMP, M_NOWAIT); + if (pfrts == NULL) { error = ENOMEM; + PF_RULES_RUNLOCK(); break; } - PF_RULES_RLOCK(); error = pfr_get_tables(&io->pfrio_table, pfrts, &io->pfrio_size, io->pfrio_flags | PFR_FLAG_USERIOCTL); PF_RULES_RUNLOCK(); @@ -2614,20 +2619,24 @@ DIOCCHANGEADDR_error: case DIOCRGETTSTATS: { struct pfioc_table *io = (struct pfioc_table *)addr; struct pfr_tstats *pfrtstats; - size_t totlen; + size_t totlen, n; if (io->pfrio_esize != sizeof(struct pfr_tstats)) { error = ENODEV; break; } + PF_RULES_WLOCK(); + n = pfr_table_count(&io->pfrio_table, io->pfrio_flags); + io->pfrio_size = min(io->pfrio_size, n); + totlen = io->pfrio_size * sizeof(struct pfr_tstats); pfrtstats = mallocarray(io->pfrio_size, - sizeof(struct pfr_tstats), M_TEMP, M_WAITOK); - if (! pfrtstats) { + sizeof(struct pfr_tstats), M_TEMP, M_NOWAIT); + if (pfrtstats == NULL) { error = ENOMEM; + PF_RULES_WUNLOCK(); break; } - PF_RULES_WLOCK(); error = pfr_get_tstats(&io->pfrio_table, pfrtstats, &io->pfrio_size, io->pfrio_flags | PFR_FLAG_USERIOCTL); PF_RULES_WUNLOCK(); @@ -2640,25 +2649,31 @@ DIOCCHANGEADDR_error: case DIOCRCLRTSTATS: { struct pfioc_table *io = (struct pfioc_table *)addr; struct pfr_table *pfrts; - size_t totlen; + size_t totlen, n; if (io->pfrio_esize != sizeof(struct pfr_table)) { error = ENODEV; break; } + + PF_RULES_WLOCK(); + n = pfr_table_count(&io->pfrio_table, io->pfrio_flags); + io->pfrio_size = min(io->pfrio_size, n); + totlen = io->pfrio_size * sizeof(struct pfr_table); pfrts = mallocarray(io->pfrio_size, sizeof(struct pfr_table), - M_TEMP, M_WAITOK); - if (! pfrts) { + M_TEMP, M_NOWAIT); + if (pfrts == NULL) { error = ENOMEM; + PF_RULES_WUNLOCK(); break; } error = copyin(io->pfrio_buffer, pfrts, totlen); if (error) { free(pfrts, M_TEMP); + PF_RULES_WUNLOCK(); break; } - PF_RULES_WLOCK(); error = pfr_clr_tstats(pfrts, io->pfrio_size, &io->pfrio_nzero, io->pfrio_flags | PFR_FLAG_USERIOCTL); PF_RULES_WUNLOCK(); @@ -2669,25 +2684,31 @@ DIOCCHANGEADDR_error: case DIOCRSETTFLAGS: { struct pfioc_table *io = (struct pfioc_table *)addr; struct pfr_table *pfrts; - size_t totlen; + size_t totlen, n; if (io->pfrio_esize != sizeof(struct pfr_table)) { error = ENODEV; break; } + + PF_RULES_WLOCK(); + n = pfr_table_count(&io->pfrio_table, io->pfrio_flags); + io->pfrio_size = min(io->pfrio_size, n); + totlen = io->pfrio_size * sizeof(struct pfr_table); pfrts = mallocarray(io->pfrio_size, sizeof(struct pfr_table), - M_TEMP, M_WAITOK); - if (! pfrts) { + M_TEMP, M_NOWAIT); + if (pfrts == NULL) { error = ENOMEM; + PF_RULES_WUNLOCK(); break; } error = copyin(io->pfrio_buffer, pfrts, totlen); if (error) { free(pfrts, M_TEMP); + PF_RULES_WUNLOCK(); break; } - PF_RULES_WLOCK(); error = pfr_set_tflags(pfrts, io->pfrio_size, io->pfrio_setflag, io->pfrio_clrflag, &io->pfrio_nchange, &io->pfrio_ndel, io->pfrio_flags | PFR_FLAG_USERIOCTL); diff --git a/sys/netpfil/pf/pf_table.c b/sys/netpfil/pf/pf_table.c index b66a0f9d43b6..ed044a96ffd1 100644 --- a/sys/netpfil/pf/pf_table.c +++ b/sys/netpfil/pf/pf_table.c @@ -177,7 +177,6 @@ static struct pfr_ktable *pfr_lookup_table(struct pfr_table *); static void pfr_clean_node_mask(struct pfr_ktable *, struct pfr_kentryworkq *); -static int pfr_table_count(struct pfr_table *, int); static int pfr_skip_table(struct pfr_table *, struct pfr_ktable *, int); static struct pfr_kentry @@ -1688,7 +1687,7 @@ pfr_fix_anchor(char *anchor) return (0); } -static int +int pfr_table_count(struct pfr_table *filter, int flags) { struct pf_ruleset *rs;