2020-12-25 06:25:38

by Randy Dunlap

Subject: [PATCH -net] net: sched: prevent invalid Scell_log shift count

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 <[email protected]>
Reported-by: [email protected]
Cc: Nogah Frankel <[email protected]>
Cc: Jamal Hadi Salim <[email protected]>
Cc: Cong Wang <[email protected]>
Cc: Jiri Pirko <[email protected]>
Cc: [email protected]
Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
---
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(-)

--- lnx-510.orig/include/net/red.h
+++ lnx-510/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;
--- lnx-510.orig/net/sched/sch_sfq.c
+++ lnx-510/net/sched/sch_sfq.c
@@ -647,7 +647,7 @@ 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);
--- lnx-510.orig/net/sched/sch_choke.c
+++ lnx-510/net/sched/sch_choke.c
@@ -362,7 +362,7 @@ 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)
--- lnx-510.orig/net/sched/sch_gred.c
+++ lnx-510/net/sched/sch_gred.c
@@ -480,7 +480,7 @@ 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)) {
NL_SET_ERR_MSG_MOD(extack, "invalid RED parameters");
return -EINVAL;
}
--- lnx-510.orig/net/sched/sch_red.c
+++ lnx-510/net/sched/sch_red.c
@@ -250,7 +250,7 @@ static int __red_change(struct Qdisc *sc
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;

err = red_get_flags(ctl->flags, TC_RED_HISTORIC_FLAGS,

2020-12-29 01:31:31

by David Miller

Subject: Re: [PATCH -net] net: sched: prevent invalid Scell_log shift count

From: Randy Dunlap <[email protected]>
Date: Thu, 24 Dec 2020 22:23:44 -0800

> 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 <[email protected]>
> Reported-by: [email protected]

Applied and queued up for -stable, thanks.