GHSA-W7R9-4GJQ-HQM4

Vulnerability from github – Published: 2025-12-30 15:30 – Updated: 2026-08-04 12:34
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

net/sched: cls_api: remove block_cb from driver_list before freeing

Error handler of tcf_block_bind() frees the whole bo->cb_list on error. However, by that time the flow_block_cb instances are already in the driver list because driver ndo_setup_tc() callback is called before that up the call chain in tcf_block_offload_cmd(). This leaves dangling pointers to freed objects in the list and causes use-after-free[0]. Fix it by also removing flow_block_cb instances from driver_list before deallocating them.

[0]: [ 279.868433] ================================================================== [ 279.869964] BUG: KASAN: slab-use-after-free in flow_block_cb_setup_simple+0x631/0x7c0 [ 279.871527] Read of size 8 at addr ffff888147e2bf20 by task tc/2963

[ 279.873151] CPU: 6 PID: 2963 Comm: tc Not tainted 6.3.0-rc6+ #4 [ 279.874273] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 279.876295] Call Trace: [ 279.876882] [ 279.877413] dump_stack_lvl+0x33/0x50 [ 279.878198] print_report+0xc2/0x610 [ 279.878987] ? flow_block_cb_setup_simple+0x631/0x7c0 [ 279.879994] kasan_report+0xae/0xe0 [ 279.880750] ? flow_block_cb_setup_simple+0x631/0x7c0 [ 279.881744] ? mlx5e_tc_reoffload_flows_work+0x240/0x240 [mlx5_core] [ 279.883047] flow_block_cb_setup_simple+0x631/0x7c0 [ 279.884027] tcf_block_offload_cmd.isra.0+0x189/0x2d0 [ 279.885037] ? tcf_block_setup+0x6b0/0x6b0 [ 279.885901] ? mutex_lock+0x7d/0xd0 [ 279.886669] ? __mutex_unlock_slowpath.constprop.0+0x2d0/0x2d0 [ 279.887844] ? ingress_init+0x1c0/0x1c0 [sch_ingress] [ 279.888846] tcf_block_get_ext+0x61c/0x1200 [ 279.889711] ingress_init+0x112/0x1c0 [sch_ingress] [ 279.890682] ? clsact_init+0x2b0/0x2b0 [sch_ingress] [ 279.891701] qdisc_create+0x401/0xea0 [ 279.892485] ? qdisc_tree_reduce_backlog+0x470/0x470 [ 279.893473] tc_modify_qdisc+0x6f7/0x16d0 [ 279.894344] ? tc_get_qdisc+0xac0/0xac0 [ 279.895213] ? mutex_lock+0x7d/0xd0 [ 279.896005] ? __mutex_lock_slowpath+0x10/0x10 [ 279.896910] rtnetlink_rcv_msg+0x5fe/0x9d0 [ 279.897770] ? rtnl_calcit.isra.0+0x2b0/0x2b0 [ 279.898672] ? __sys_sendmsg+0xb5/0x140 [ 279.899494] ? do_syscall_64+0x3d/0x90 [ 279.900302] ? entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 279.901337] ? kasan_save_stack+0x2e/0x40 [ 279.902177] ? kasan_save_stack+0x1e/0x40 [ 279.903058] ? kasan_set_track+0x21/0x30 [ 279.903913] ? kasan_save_free_info+0x2a/0x40 [ 279.904836] ? _kasanslab_free+0x11a/0x1b0 [ 279.905741] ? kmem_cache_free+0x179/0x400 [ 279.906599] netlink_rcv_skb+0x12c/0x360 [ 279.907450] ? rtnl_calcit.isra.0+0x2b0/0x2b0 [ 279.908360] ? netlink_ack+0x1550/0x1550 [ 279.909192] ? rhashtable_walk_peek+0x170/0x170 [ 279.910135] ? kmem_cache_alloc_node+0x1af/0x390 [ 279.911086] ? _copy_from_iter+0x3d6/0xc70 [ 279.912031] netlink_unicast+0x553/0x790 [ 279.912864] ? netlink_attachskb+0x6a0/0x6a0 [ 279.913763] ? netlink_recvmsg+0x416/0xb50 [ 279.914627] netlink_sendmsg+0x7a1/0xcb0 [ 279.915473] ? netlink_unicast+0x790/0x790 [ 279.916334] ? iovec_from_user.part.0+0x4d/0x220 [ 279.917293] ? netlink_unicast+0x790/0x790 [ 279.918159] sock_sendmsg+0xc5/0x190 [ 279.918938] __sys_sendmsg+0x535/0x6b0 [ 279.919813] ? import_iovec+0x7/0x10 [ 279.920601] ? kernel_sendmsg+0x30/0x30 [ 279.921423] ? __copy_msghdr+0x3c0/0x3c0 [ 279.922254] ? import_iovec+0x7/0x10 [ 279.923041] syssendmsg+0xeb/0x170 [ 279.923854] ? copy_msghdr_from_user+0x110/0x110 [ 279.924797] ? _sys_recvmsg+0xd9/0x130 [ 279.925630] ? __perf_event_task_sched_in+0x183/0x470 [ 279.926656] ? syssendmsg+0x170/0x170 [ 279.927529] ? ctx_sched_in+0x530/0x530 [ 279.928369] ? update_curr+0x283/0x4f0 [ 279.929185] ? perf_event_update_userpage+0x570/0x570 [ 279.930201] ? fget_light+0x57/0x520 [ 279.931023] ? __switch_to+0x53d/0xe70 [ 27 ---truncated---

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2023-54193"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-30T13:16:07Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: remove block_cb from driver_list before freeing\n\nError handler of tcf_block_bind() frees the whole bo-\u003ecb_list on error.\nHowever, by that time the flow_block_cb instances are already in the driver\nlist because driver ndo_setup_tc() callback is called before that up the\ncall chain in tcf_block_offload_cmd(). This leaves dangling pointers to\nfreed objects in the list and causes use-after-free[0]. Fix it by also\nremoving flow_block_cb instances from driver_list before deallocating them.\n\n[0]:\n[  279.868433] ==================================================================\n[  279.869964] BUG: KASAN: slab-use-after-free in flow_block_cb_setup_simple+0x631/0x7c0\n[  279.871527] Read of size 8 at addr ffff888147e2bf20 by task tc/2963\n\n[  279.873151] CPU: 6 PID: 2963 Comm: tc Not tainted 6.3.0-rc6+ #4\n[  279.874273] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n[  279.876295] Call Trace:\n[  279.876882]  \u003cTASK\u003e\n[  279.877413]  dump_stack_lvl+0x33/0x50\n[  279.878198]  print_report+0xc2/0x610\n[  279.878987]  ? flow_block_cb_setup_simple+0x631/0x7c0\n[  279.879994]  kasan_report+0xae/0xe0\n[  279.880750]  ? flow_block_cb_setup_simple+0x631/0x7c0\n[  279.881744]  ? mlx5e_tc_reoffload_flows_work+0x240/0x240 [mlx5_core]\n[  279.883047]  flow_block_cb_setup_simple+0x631/0x7c0\n[  279.884027]  tcf_block_offload_cmd.isra.0+0x189/0x2d0\n[  279.885037]  ? tcf_block_setup+0x6b0/0x6b0\n[  279.885901]  ? mutex_lock+0x7d/0xd0\n[  279.886669]  ? __mutex_unlock_slowpath.constprop.0+0x2d0/0x2d0\n[  279.887844]  ? ingress_init+0x1c0/0x1c0 [sch_ingress]\n[  279.888846]  tcf_block_get_ext+0x61c/0x1200\n[  279.889711]  ingress_init+0x112/0x1c0 [sch_ingress]\n[  279.890682]  ? clsact_init+0x2b0/0x2b0 [sch_ingress]\n[  279.891701]  qdisc_create+0x401/0xea0\n[  279.892485]  ? qdisc_tree_reduce_backlog+0x470/0x470\n[  279.893473]  tc_modify_qdisc+0x6f7/0x16d0\n[  279.894344]  ? tc_get_qdisc+0xac0/0xac0\n[  279.895213]  ? mutex_lock+0x7d/0xd0\n[  279.896005]  ? __mutex_lock_slowpath+0x10/0x10\n[  279.896910]  rtnetlink_rcv_msg+0x5fe/0x9d0\n[  279.897770]  ? rtnl_calcit.isra.0+0x2b0/0x2b0\n[  279.898672]  ? __sys_sendmsg+0xb5/0x140\n[  279.899494]  ? do_syscall_64+0x3d/0x90\n[  279.900302]  ? entry_SYSCALL_64_after_hwframe+0x46/0xb0\n[  279.901337]  ? kasan_save_stack+0x2e/0x40\n[  279.902177]  ? kasan_save_stack+0x1e/0x40\n[  279.903058]  ? kasan_set_track+0x21/0x30\n[  279.903913]  ? kasan_save_free_info+0x2a/0x40\n[  279.904836]  ? ____kasan_slab_free+0x11a/0x1b0\n[  279.905741]  ? kmem_cache_free+0x179/0x400\n[  279.906599]  netlink_rcv_skb+0x12c/0x360\n[  279.907450]  ? rtnl_calcit.isra.0+0x2b0/0x2b0\n[  279.908360]  ? netlink_ack+0x1550/0x1550\n[  279.909192]  ? rhashtable_walk_peek+0x170/0x170\n[  279.910135]  ? kmem_cache_alloc_node+0x1af/0x390\n[  279.911086]  ? _copy_from_iter+0x3d6/0xc70\n[  279.912031]  netlink_unicast+0x553/0x790\n[  279.912864]  ? netlink_attachskb+0x6a0/0x6a0\n[  279.913763]  ? netlink_recvmsg+0x416/0xb50\n[  279.914627]  netlink_sendmsg+0x7a1/0xcb0\n[  279.915473]  ? netlink_unicast+0x790/0x790\n[  279.916334]  ? iovec_from_user.part.0+0x4d/0x220\n[  279.917293]  ? netlink_unicast+0x790/0x790\n[  279.918159]  sock_sendmsg+0xc5/0x190\n[  279.918938]  ____sys_sendmsg+0x535/0x6b0\n[  279.919813]  ? import_iovec+0x7/0x10\n[  279.920601]  ? kernel_sendmsg+0x30/0x30\n[  279.921423]  ? __copy_msghdr+0x3c0/0x3c0\n[  279.922254]  ? import_iovec+0x7/0x10\n[  279.923041]  ___sys_sendmsg+0xeb/0x170\n[  279.923854]  ? copy_msghdr_from_user+0x110/0x110\n[  279.924797]  ? ___sys_recvmsg+0xd9/0x130\n[  279.925630]  ? __perf_event_task_sched_in+0x183/0x470\n[  279.926656]  ? ___sys_sendmsg+0x170/0x170\n[  279.927529]  ? ctx_sched_in+0x530/0x530\n[  279.928369]  ? update_curr+0x283/0x4f0\n[  279.929185]  ? perf_event_update_userpage+0x570/0x570\n[  279.930201]  ? __fget_light+0x57/0x520\n[  279.931023]  ? __switch_to+0x53d/0xe70\n[  27\n---truncated---",
  "id": "GHSA-w7r9-4gjq-hqm4",
  "modified": "2026-08-04T12:34:48Z",
  "published": "2025-12-30T15:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-54193"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/26aec72429a05e917d574eca0efc5306c63a8862"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/55866fe3fded3ce94ac3fc1bb3dfce654282f483"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7311c8be3755611bf6edea4dfbeb190b4bdd489f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7b7a74ed303d532fb73ae4b1697f16a0fea89cd0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cb145932fcf6814e7e95e467eb70e7849a845ae9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cc5fe387c6294d0471cb7ed064efac97fac65ccc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/da94a7781fc3c92e7df7832bc2746f4d39bc624e"
    }
  ],
  "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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