GHSA-VWV2-838R-2Q6P
Vulnerability from github – Published: 2025-07-25 18:30 – Updated: 2025-12-22 21:30In the Linux kernel, the following vulnerability has been resolved:
tipc: Fix use-after-free in tipc_conn_close().
syzbot reported a null-ptr-deref in tipc_conn_close() during netns dismantle. [0]
tipc_topsrv_stop() iterates tipc_net(net)->topsrv->conn_idr and calls tipc_conn_close() for each tipc_conn.
The problem is that tipc_conn_close() is called after releasing the IDR lock.
At the same time, there might be tipc_conn_recv_work() running and it could call tipc_conn_close() for the same tipc_conn and release its last ->kref.
Once we release the IDR lock in tipc_topsrv_stop(), there is no guarantee that the tipc_conn is alive.
Let's hold the ref before releasing the lock and put the ref after tipc_conn_close() in tipc_topsrv_stop().
[0]: BUG: KASAN: use-after-free in tipc_conn_close+0x122/0x140 net/tipc/topsrv.c:165 Read of size 8 at addr ffff888099305a08 by task kworker/u4:3/435
CPU: 0 PID: 435 Comm: kworker/u4:3 Not tainted 4.19.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433 tipc_conn_close+0x122/0x140 net/tipc/topsrv.c:165 tipc_topsrv_stop net/tipc/topsrv.c:701 [inline] tipc_topsrv_exit_net+0x27b/0x5c0 net/tipc/topsrv.c:722 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:553 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Allocated by task 23: kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] tipc_conn_alloc+0x43/0x4f0 net/tipc/topsrv.c:192 tipc_topsrv_accept+0x1b5/0x280 net/tipc/topsrv.c:470 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Freed by task 23: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 tipc_conn_kref_release net/tipc/topsrv.c:150 [inline] kref_put include/linux/kref.h:70 [inline] conn_put+0x2cd/0x3a0 net/tipc/topsrv.c:155 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
The buggy address belongs to the object at ffff888099305a00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 8 bytes inside of 512-byte region [ffff888099305a00, ffff888099305c00) The buggy address belongs to the page: page:ffffea000264c140 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffffea00028b6b88 ffffea0002cd2b08 ffff88813bff0940 raw: 0000000000000000 ffff888099305000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff888099305900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888099305980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888099305a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888099305a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888099305b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
{
"affected": [],
"aliases": [
"CVE-2025-38464"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-25T16:15:32Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: Fix use-after-free in tipc_conn_close().\n\nsyzbot reported a null-ptr-deref in tipc_conn_close() during netns\ndismantle. [0]\n\ntipc_topsrv_stop() iterates tipc_net(net)-\u003etopsrv-\u003econn_idr and calls\ntipc_conn_close() for each tipc_conn.\n\nThe problem is that tipc_conn_close() is called after releasing the\nIDR lock.\n\nAt the same time, there might be tipc_conn_recv_work() running and it\ncould call tipc_conn_close() for the same tipc_conn and release its\nlast -\u003ekref.\n\nOnce we release the IDR lock in tipc_topsrv_stop(), there is no\nguarantee that the tipc_conn is alive.\n\nLet\u0027s hold the ref before releasing the lock and put the ref after\ntipc_conn_close() in tipc_topsrv_stop().\n\n[0]:\nBUG: KASAN: use-after-free in tipc_conn_close+0x122/0x140 net/tipc/topsrv.c:165\nRead of size 8 at addr ffff888099305a08 by task kworker/u4:3/435\n\nCPU: 0 PID: 435 Comm: kworker/u4:3 Not tainted 4.19.204-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nWorkqueue: netns cleanup_net\nCall Trace:\n __dump_stack lib/dump_stack.c:77 [inline]\n dump_stack+0x1fc/0x2ef lib/dump_stack.c:118\n print_address_description.cold+0x54/0x219 mm/kasan/report.c:256\n kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354\n kasan_report mm/kasan/report.c:412 [inline]\n __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433\n tipc_conn_close+0x122/0x140 net/tipc/topsrv.c:165\n tipc_topsrv_stop net/tipc/topsrv.c:701 [inline]\n tipc_topsrv_exit_net+0x27b/0x5c0 net/tipc/topsrv.c:722\n ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153\n cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:553\n process_one_work+0x864/0x1570 kernel/workqueue.c:2153\n worker_thread+0x64c/0x1130 kernel/workqueue.c:2296\n kthread+0x33f/0x460 kernel/kthread.c:259\n ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415\n\nAllocated by task 23:\n kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625\n kmalloc include/linux/slab.h:515 [inline]\n kzalloc include/linux/slab.h:709 [inline]\n tipc_conn_alloc+0x43/0x4f0 net/tipc/topsrv.c:192\n tipc_topsrv_accept+0x1b5/0x280 net/tipc/topsrv.c:470\n process_one_work+0x864/0x1570 kernel/workqueue.c:2153\n worker_thread+0x64c/0x1130 kernel/workqueue.c:2296\n kthread+0x33f/0x460 kernel/kthread.c:259\n ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415\n\nFreed by task 23:\n __cache_free mm/slab.c:3503 [inline]\n kfree+0xcc/0x210 mm/slab.c:3822\n tipc_conn_kref_release net/tipc/topsrv.c:150 [inline]\n kref_put include/linux/kref.h:70 [inline]\n conn_put+0x2cd/0x3a0 net/tipc/topsrv.c:155\n process_one_work+0x864/0x1570 kernel/workqueue.c:2153\n worker_thread+0x64c/0x1130 kernel/workqueue.c:2296\n kthread+0x33f/0x460 kernel/kthread.c:259\n ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415\n\nThe buggy address belongs to the object at ffff888099305a00\n which belongs to the cache kmalloc-512 of size 512\nThe buggy address is located 8 bytes inside of\n 512-byte region [ffff888099305a00, ffff888099305c00)\nThe buggy address belongs to the page:\npage:ffffea000264c140 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0\nflags: 0xfff00000000100(slab)\nraw: 00fff00000000100 ffffea00028b6b88 ffffea0002cd2b08 ffff88813bff0940\nraw: 0000000000000000 ffff888099305000 0000000100000006 0000000000000000\npage dumped because: kasan: bad access detected\n\nMemory state around the buggy address:\n ffff888099305900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff888099305980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\n\u003effff888099305a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ^\n ffff888099305a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff888099305b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb",
"id": "GHSA-vwv2-838r-2q6p",
"modified": "2025-12-22T21:30:29Z",
"published": "2025-07-25T18:30:40Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38464"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/03dcdd2558e1e55bf843822fe4363dcb48743f2b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/15a6f4971e2f157d57e09ea748d1fbc714277aa4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1dbf7cd2454a28b1da700085b99346b5445aeabb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3b89e17b2fd64012682bed158d9eb3d2e96dec42"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/50aa2d121bc2cfe2d825f8a331ea75dfaaab6a50"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/667eeab4999e981c96b447a4df5f20bdf5c26f13"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/be4b8392da7978294f2f368799d29dd509fb6c4d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dab8ded2e5ff41012a6ff400b44dbe76ccf3592a"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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