| From f6a017529f7ec1063c5db68eb94724a3977385a2 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 8 Nov 2021 10:08:15 -0800 |
| Subject: net/sched: sch_taprio: fix undefined behavior in ktime_mono_to_any |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| [ Upstream commit 6dc25401cba4d428328eade8ceae717633fdd702 ] |
| |
| 1) if q->tk_offset == TK_OFFS_MAX, then get_tcp_tstamp() calls |
| ktime_mono_to_any() with out-of-bound value. |
| |
| 2) if q->tk_offset is changed in taprio_parse_clockid(), |
| taprio_get_time() might also call ktime_mono_to_any() |
| with out-of-bound value as sysbot found: |
| |
| UBSAN: array-index-out-of-bounds in kernel/time/timekeeping.c:908:27 |
| index 3 is out of range for type 'ktime_t *[3]' |
| CPU: 1 PID: 25668 Comm: kworker/u4:0 Not tainted 5.15.0-syzkaller #0 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 |
| Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet |
| Call Trace: |
| <TASK> |
| __dump_stack lib/dump_stack.c:88 [inline] |
| dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 |
| ubsan_epilogue+0xb/0x5a lib/ubsan.c:151 |
| __ubsan_handle_out_of_bounds.cold+0x62/0x6c lib/ubsan.c:291 |
| ktime_mono_to_any+0x1d4/0x1e0 kernel/time/timekeeping.c:908 |
| get_tcp_tstamp net/sched/sch_taprio.c:322 [inline] |
| get_packet_txtime net/sched/sch_taprio.c:353 [inline] |
| taprio_enqueue_one+0x5b0/0x1460 net/sched/sch_taprio.c:420 |
| taprio_enqueue+0x3b1/0x730 net/sched/sch_taprio.c:485 |
| dev_qdisc_enqueue+0x40/0x300 net/core/dev.c:3785 |
| __dev_xmit_skb net/core/dev.c:3869 [inline] |
| __dev_queue_xmit+0x1f6e/0x3630 net/core/dev.c:4194 |
| batadv_send_skb_packet+0x4a9/0x5f0 net/batman-adv/send.c:108 |
| batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:393 [inline] |
| batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:421 [inline] |
| batadv_iv_send_outstanding_bat_ogm_packet+0x6d7/0x8e0 net/batman-adv/bat_iv_ogm.c:1701 |
| process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 |
| worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 |
| kthread+0x405/0x4f0 kernel/kthread.c:327 |
| ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 |
| |
| Fixes: 7ede7b03484b ("taprio: make clock reference conversions easier") |
| Fixes: 54002066100b ("taprio: Adjust timestamps for TCP packets") |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Cc: Vedang Patel <vedang.patel@intel.com> |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Reviewed-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> |
| Link: https://lore.kernel.org/r/20211108180815.1822479-1-eric.dumazet@gmail.com |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/sched/sch_taprio.c | 27 +++++++++++++++++---------- |
| 1 file changed, 17 insertions(+), 10 deletions(-) |
| |
| diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c |
| index e14a66ce4884d..b268e61304515 100644 |
| --- a/net/sched/sch_taprio.c |
| +++ b/net/sched/sch_taprio.c |
| @@ -94,18 +94,22 @@ static ktime_t sched_base_time(const struct sched_gate_list *sched) |
| return ns_to_ktime(sched->base_time); |
| } |
| |
| -static ktime_t taprio_get_time(struct taprio_sched *q) |
| +static ktime_t taprio_mono_to_any(const struct taprio_sched *q, ktime_t mono) |
| { |
| - ktime_t mono = ktime_get(); |
| + /* This pairs with WRITE_ONCE() in taprio_parse_clockid() */ |
| + enum tk_offsets tk_offset = READ_ONCE(q->tk_offset); |
| |
| - switch (q->tk_offset) { |
| + switch (tk_offset) { |
| case TK_OFFS_MAX: |
| return mono; |
| default: |
| - return ktime_mono_to_any(mono, q->tk_offset); |
| + return ktime_mono_to_any(mono, tk_offset); |
| } |
| +} |
| |
| - return KTIME_MAX; |
| +static ktime_t taprio_get_time(const struct taprio_sched *q) |
| +{ |
| + return taprio_mono_to_any(q, ktime_get()); |
| } |
| |
| static void taprio_free_sched_cb(struct rcu_head *head) |
| @@ -321,7 +325,7 @@ static ktime_t get_tcp_tstamp(struct taprio_sched *q, struct sk_buff *skb) |
| return 0; |
| } |
| |
| - return ktime_mono_to_any(skb->skb_mstamp_ns, q->tk_offset); |
| + return taprio_mono_to_any(q, skb->skb_mstamp_ns); |
| } |
| |
| /* There are a few scenarios where we will have to modify the txtime from |
| @@ -1342,6 +1346,7 @@ static int taprio_parse_clockid(struct Qdisc *sch, struct nlattr **tb, |
| } |
| } else if (tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]) { |
| int clockid = nla_get_s32(tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]); |
| + enum tk_offsets tk_offset; |
| |
| /* We only support static clockids and we don't allow |
| * for it to be modified after the first init. |
| @@ -1356,22 +1361,24 @@ static int taprio_parse_clockid(struct Qdisc *sch, struct nlattr **tb, |
| |
| switch (clockid) { |
| case CLOCK_REALTIME: |
| - q->tk_offset = TK_OFFS_REAL; |
| + tk_offset = TK_OFFS_REAL; |
| break; |
| case CLOCK_MONOTONIC: |
| - q->tk_offset = TK_OFFS_MAX; |
| + tk_offset = TK_OFFS_MAX; |
| break; |
| case CLOCK_BOOTTIME: |
| - q->tk_offset = TK_OFFS_BOOT; |
| + tk_offset = TK_OFFS_BOOT; |
| break; |
| case CLOCK_TAI: |
| - q->tk_offset = TK_OFFS_TAI; |
| + tk_offset = TK_OFFS_TAI; |
| break; |
| default: |
| NL_SET_ERR_MSG(extack, "Invalid 'clockid'"); |
| err = -EINVAL; |
| goto out; |
| } |
| + /* This pairs with READ_ONCE() in taprio_mono_to_any */ |
| + WRITE_ONCE(q->tk_offset, tk_offset); |
| |
| q->clockid = clockid; |
| } else { |
| -- |
| 2.33.0 |
| |