ghsa-mwqv-w7x4-3822
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
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 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.
Also, we add a new tdc test case for this issue.
[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: 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 Modules linked in:
{
"affected": [],
"aliases": [
"CVE-2023-54251"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-30T13:16:13Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: taprio: Limit TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME to INT_MAX.\n\nsyzkaller found zero division error [0] in div_s64_rem() called from\nget_cycle_time_elapsed(), where sched-\u003ecycle_time is the divisor.\n\nWe have tests in parse_taprio_schedule() so that cycle_time will never\nbe 0, and actually cycle_time is not 0 in get_cycle_time_elapsed().\n\nThe problem is that the types of divisor are different; cycle_time is\ns64, but the argument of div_s64_rem() is s32.\n\nsyzkaller fed this input and 0x100000000 is cast to s32 to be 0.\n\n @TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME={0xc, 0x8, 0x100000000}\n\nWe use s64 for cycle_time to cast it to ktime_t, so let\u0027s keep it and\nset max for cycle_time.\n\nWhile at it, we prevent overflow in setup_txtime() and add another\ntest in parse_taprio_schedule() to check if cycle_time overflows.\n\nAlso, we add a new tdc test case for this issue.\n\n[0]:\ndivide error: 0000 [#1] PREEMPT SMP KASAN NOPTI\nCPU: 1 PID: 103 Comm: kworker/1:3 Not tainted 6.5.0-rc1-00330-g60cc1f7d0605 #3\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\nWorkqueue: ipv6_addrconf addrconf_dad_work\nRIP: 0010:div_s64_rem include/linux/math64.h:42 [inline]\nRIP: 0010:get_cycle_time_elapsed net/sched/sch_taprio.c:223 [inline]\nRIP: 0010:find_entry_to_transmit+0x252/0x7e0 net/sched/sch_taprio.c:344\nCode: 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 \u003c48\u003e f7 fe 48 29 d1 48 8d 04 0f 49 89 cc 48 89 44 24 20 49 8d 85 10\nRSP: 0018:ffffc90000acf260 EFLAGS: 00010206\nRAX: 177450e0347560cf RBX: 0000000000000000 RCX: 177450e0347560cf\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000100000000\nRBP: 0000000000000056 R08: 0000000000000000 R09: ffffed10020a0934\nR10: ffff8880105049a7 R11: ffff88806cf3a520 R12: ffff888010504800\nR13: ffff88800c00d800 R14: ffff8880105049a0 R15: 0000000000000000\nFS: 0000000000000000(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007f0edf84f0e8 CR3: 000000000d73c002 CR4: 0000000000770ee0\nPKRU: 55555554\nCall Trace:\n \u003cTASK\u003e\n get_packet_txtime net/sched/sch_taprio.c:508 [inline]\n taprio_enqueue_one+0x900/0xff0 net/sched/sch_taprio.c:577\n taprio_enqueue+0x378/0xae0 net/sched/sch_taprio.c:658\n dev_qdisc_enqueue+0x46/0x170 net/core/dev.c:3732\n __dev_xmit_skb net/core/dev.c:3821 [inline]\n __dev_queue_xmit+0x1b2f/0x3000 net/core/dev.c:4169\n dev_queue_xmit include/linux/netdevice.h:3088 [inline]\n neigh_resolve_output net/core/neighbour.c:1552 [inline]\n neigh_resolve_output+0x4a7/0x780 net/core/neighbour.c:1532\n neigh_output include/net/neighbour.h:544 [inline]\n ip6_finish_output2+0x924/0x17d0 net/ipv6/ip6_output.c:135\n __ip6_finish_output+0x620/0xaa0 net/ipv6/ip6_output.c:196\n ip6_finish_output net/ipv6/ip6_output.c:207 [inline]\n NF_HOOK_COND include/linux/netfilter.h:292 [inline]\n ip6_output+0x206/0x410 net/ipv6/ip6_output.c:228\n dst_output include/net/dst.h:458 [inline]\n NF_HOOK.constprop.0+0xea/0x260 include/linux/netfilter.h:303\n ndisc_send_skb+0x872/0xe80 net/ipv6/ndisc.c:508\n ndisc_send_ns+0xb5/0x130 net/ipv6/ndisc.c:666\n addrconf_dad_work+0xc14/0x13f0 net/ipv6/addrconf.c:4175\n process_one_work+0x92c/0x13a0 kernel/workqueue.c:2597\n worker_thread+0x60f/0x1240 kernel/workqueue.c:2748\n kthread+0x2fe/0x3f0 kernel/kthread.c:389\n ret_from_fork+0x2c/0x50 arch/x86/entry/entry_64.S:308\n \u003c/TASK\u003e\nModules linked in:",
"id": "GHSA-mwqv-w7x4-3822",
"modified": "2025-12-30T15:30:33Z",
"published": "2025-12-30T15:30:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-54251"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0b45af982a4df0b14fb8669ee2a871cfdfa6a39c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/57b3fe08ae06ef11af007b4a182629b12a961e30"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e739718444f7bf2fa3d70d101761ad83056ca628"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f04f6d9b3b060f7e11219a65a76da65f1489e391"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
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