[PATCH 4.19 35/77] net: sched: prevent invalid Scell_log shift count

Greg Kroah-Hartman
2021-01-11T13:52:02Z

From: Randy Dunlap <rdunlap@infradead.org>

[ Upstream commit bd1248f1ddbc48b0c30565fce897a3b6423313b8 ]

Check Scell_log shift size in red_check_params() and modify all callers
of red_check_params() to pass Scell_log.

This prevents a shift out-of-bounds as detected by UBSAN:
UBSAN: shift-out-of-bounds in ./include/net/red.h:252:22
shift exponent 72 is too large for 32-bit type 'int'

Fixes: 8afa10cbe281 ("net_sched: red: Avoid illegal values")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: syzbot+97c5bd9cc81eca63d36e@syzkaller.appspotmail.com
Cc: Nogah Frankel <nogahf@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/red.h | 4 +++-
net/sched/sch_choke.c | 2 +-
net/sched/sch_gred.c | 2 +-
net/sched/sch_red.c | 2 +-
net/sched/sch_sfq.c | 2 +-
5 files changed, 7 insertions(+), 5 deletions(-)

--- a/include/net/red.h
+++ b/include/net/red.h
@@ -168,12 +168,14 @@ static inline void red_set_vars(struct r
v->qcount = -1;
}

-static inline bool red_check_params(u32 qth_min, u32 qth_max, u8 Wlog)
+static inline bool red_check_params(u32 qth_min, u32 qth_max, u8 Wlog, u8 Scell_log)
{
if (fls(qth_min) + Wlog > 32)
return false;
if (fls(qth_max) + Wlog > 32)
return false;
+ if (Scell_log >= 32)
+ return false;
if (qth_max < qth_min)
return false;
return true;
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -371,7 +371,7 @@ static int choke_change(struct Qdisc *sc

ctl = nla_data(tb[TCA_CHOKE_PARMS]);

- if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
+ if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log))
return -EINVAL;

if (ctl->limit > CHOKE_MAX_QUEUE)
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -357,7 +357,7 @@ static inline int gred_change_vq(struct
struct gred_sched *table = qdisc_priv(sch);
struct gred_sched_data *q = table->tab[dp];

- if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
+ if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log))
return -EINVAL;

if (!q) {
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -214,7 +214,7 @@ static int red_change(struct Qdisc *sch,
max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;

ctl = nla_data(tb[TCA_RED_PARMS]);
- if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
+ if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log))
return -EINVAL;

if (ctl->limit > 0) {
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -651,7 +651,7 @@ static int sfq_change(struct Qdisc *sch,
}

if (ctl_v1 && !red_check_params(ctl_v1->qth_min, ctl_v1->qth_max,
- ctl_v1->Wlog))
+ ctl_v1->Wlog, ctl_v1->Scell_log))
return -EINVAL;
if (ctl_v1 && ctl_v1->qth_min) {
p = kmalloc(sizeof(*p), GFP_KERNEL);