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Message-ID: <20230726191928.50768-1-kuniyu@amazon.com>
Date: Wed, 26 Jul 2023 12:19:28 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>, Vinicius Costa Gomes <vinicius.gomes@...el.com>, "Jamal
Hadi Salim" <jhs@...atatu.com>, Cong Wang <xiyou.wangcong@...il.com>, "Jiri
Pirko" <jiri@...nulli.us>
CC: Vedang Patel <vedang.patel@...el.com>, Kuniyuki Iwashima
<kuniyu@...zon.com>, Kuniyuki Iwashima <kuni1840@...il.com>,
<netdev@...r.kernel.org>, syzkaller <syzkaller@...glegroups.com>
Subject: [PATCH v2 net] net/sched: taprio: Limit TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME to INT_MAX.
syzkaller found zero division error [0] in div_s64_rem() called from
get_cycle_time_elapsed(), where sched->cycle_time is the divisor.
We have tests in parse_taprio_schedule() so that cycle_time will never
be 0, and actually cycle_time is not 0 in get_cycle_time_elapsed().
The problem is that the types of divisor are different; cycle_time is
s64, but the argument of div_s64_rem() is s32.
syzkaller fed this input and 0x100000000 is cast to s32 to be 0.
@TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME={0xc, 0x8, 0x100000000}
We use s64 for cycle_time to cast it to ktime_t, so let's keep it and
set min/max for cycle_time.
While at it, we prevent overflow in setup_txtime() and add another
test in parse_taprio_schedule() to check if cycle_time overflows.
[0]:
divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 1 PID: 103 Comm: kworker/1:3 Not tainted 6.5.0-rc1-00330-g60cc1f7d0605 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:div_s64_rem include/linux/math64.h:42 [inline]
RIP: 0010:get_cycle_time_elapsed net/sched/sch_taprio.c:223 [inline]
RIP: 0010:find_entry_to_transmit+0x252/0x7e0 net/sched/sch_taprio.c:344
Code: 3c 02 00 0f 85 5e 05 00 00 48 8b 4c 24 08 4d 8b bd 40 01 00 00 48 8b 7c 24 48 48 89 c8 4c 29 f8 48 63 f7 48 99 48 89 74 24 70 <48> f7 fe 48 29 d1 48 8d 04 0f 49 89 cc 48 89 44 24 20 49 8d 85 10
RSP: 0018:ffffc90000acf260 EFLAGS: 00010206
RAX: 177450e0347560cf RBX: 0000000000000000 RCX: 177450e0347560cf
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000100000000
RBP: 0000000000000056 R08: 0000000000000000 R09: ffffed10020a0934
R10: ffff8880105049a7 R11: ffff88806cf3a520 R12: ffff888010504800
R13: ffff88800c00d800 R14: ffff8880105049a0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0edf84f0e8 CR3: 000000000d73c002 CR4: 0000000000770ee0
PKRU: 55555554
Call Trace:
<TASK>
get_packet_txtime net/sched/sch_taprio.c:508 [inline]
taprio_enqueue_one+0x900/0xff0 net/sched/sch_taprio.c:577
taprio_enqueue+0x378/0xae0 net/sched/sch_taprio.c:658
dev_qdisc_enqueue+0x46/0x170 net/core/dev.c:3732
__dev_xmit_skb net/core/dev.c:3821 [inline]
__dev_queue_xmit+0x1b2f/0x3000 net/core/dev.c:4169
dev_queue_xmit include/linux/netdevice.h:3088 [inline]
neigh_resolve_output net/core/neighbour.c:1552 [inline]
neigh_resolve_output+0x4a7/0x780 net/core/neighbour.c:1532
neigh_output include/net/neighbour.h:544 [inline]
ip6_finish_output2+0x924/0x17d0 net/ipv6/ip6_output.c:135
__ip6_finish_output+0x620/0xaa0 net/ipv6/ip6_output.c:196
ip6_finish_output net/ipv6/ip6_output.c:207 [inline]
NF_HOOK_COND include/linux/netfilter.h:292 [inline]
ip6_output+0x206/0x410 net/ipv6/ip6_output.c:228
dst_output include/net/dst.h:458 [inline]
NF_HOOK.constprop.0+0xea/0x260 include/linux/netfilter.h:303
ndisc_send_skb+0x872/0xe80 net/ipv6/ndisc.c:508
ndisc_send_ns+0xb5/0x130 net/ipv6/ndisc.c:666
addrconf_dad_work+0xc14/0x13f0 net/ipv6/addrconf.c:4175
process_one_work+0x92c/0x13a0 kernel/workqueue.c:2597
worker_thread+0x60f/0x1240 kernel/workqueue.c:2748
kthread+0x2fe/0x3f0 kernel/kthread.c:389
ret_from_fork+0x2c/0x50 arch/x86/entry/entry_64.S:308
</TASK>
Modules linked in:
Fixes: 4cfd5779bd6e ("taprio: Add support for txtime-assist mode")
Reported-by: syzkaller <syzkaller@...glegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
Co-developed-by: Eric Dumazet <edumazet@...gle.com>
---
v2
* Prevent overflow in setup_txtime() and parse_taprio_schedule()
and add extack for such cases
(Added cycle < 0 test in addition to Eric's suggestion)
v1: https://lore.kernel.org/netdev/20230726011432.19250-1-kuniyu@amazon.com/
---
net/sched/sch_taprio.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 717ae51d94a0..61ec0c237440 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -1015,6 +1015,11 @@ static const struct nla_policy taprio_tc_policy[TCA_TAPRIO_TC_ENTRY_MAX + 1] = {
TC_FP_PREEMPTIBLE),
};
+static struct netlink_range_validation_signed taprio_cycle_time_range = {
+ .min = 1,
+ .max = INT_MAX,
+};
+
static const struct nla_policy taprio_policy[TCA_TAPRIO_ATTR_MAX + 1] = {
[TCA_TAPRIO_ATTR_PRIOMAP] = {
.len = sizeof(struct tc_mqprio_qopt)
@@ -1023,7 +1028,8 @@ static const struct nla_policy taprio_policy[TCA_TAPRIO_ATTR_MAX + 1] = {
[TCA_TAPRIO_ATTR_SCHED_BASE_TIME] = { .type = NLA_S64 },
[TCA_TAPRIO_ATTR_SCHED_SINGLE_ENTRY] = { .type = NLA_NESTED },
[TCA_TAPRIO_ATTR_SCHED_CLOCKID] = { .type = NLA_S32 },
- [TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME] = { .type = NLA_S64 },
+ [TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME] =
+ NLA_POLICY_FULL_RANGE_SIGNED(NLA_S64, &taprio_cycle_time_range),
[TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME_EXTENSION] = { .type = NLA_S64 },
[TCA_TAPRIO_ATTR_FLAGS] = { .type = NLA_U32 },
[TCA_TAPRIO_ATTR_TXTIME_DELAY] = { .type = NLA_U32 },
@@ -1159,6 +1165,11 @@ static int parse_taprio_schedule(struct taprio_sched *q, struct nlattr **tb,
return -EINVAL;
}
+ if (cycle < 0 || cycle > INT_MAX) {
+ NL_SET_ERR_MSG(extack, "'cycle_time' is too big");
+ return -EINVAL;
+ }
+
new->cycle_time = cycle;
}
@@ -1347,7 +1358,7 @@ static void setup_txtime(struct taprio_sched *q,
struct sched_gate_list *sched, ktime_t base)
{
struct sched_entry *entry;
- u32 interval = 0;
+ u64 interval = 0;
list_for_each_entry(entry, &sched->entries, list) {
entry->next_txtime = ktime_add_ns(base, interval);
--
2.30.2
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