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Message-ID: <2025123028-CVE-2023-54193-50c4@gregkh>
Date: Tue, 30 Dec 2025 13:10:01 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-54193: net/sched: cls_api: remove block_cb from driver_list before freeing
From: Greg Kroah-Hartman <gregkh@...nel.org>
Description
===========
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] <TASK>
[ 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] ? ____kasan_slab_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] ___sys_sendmsg+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] ? ___sys_sendmsg+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
[ 279.931846] ? sockfd_lookup_light+0x1a/0x140
[ 279.932761] __sys_sendmsg+0xb5/0x140
[ 279.933560] ? __sys_sendmsg_sock+0x20/0x20
[ 279.934436] ? fpregs_assert_state_consistent+0x1d/0xa0
[ 279.935490] do_syscall_64+0x3d/0x90
[ 279.936300] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 279.937311] RIP: 0033:0x7f21c814f887
[ 279.938085] Code: 0a 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
[ 279.941448] RSP: 002b:00007fff11efd478 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 279.942964] RAX: ffffffffffffffda RBX: 0000000064401979 RCX: 00007f21c814f887
[ 279.944337] RDX: 0000000000000000 RSI: 00007fff11efd4e0 RDI: 0000000000000003
[ 279.945660] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
[ 279.947003] R10: 00007f21c8008708 R11: 0000000000000246 R12: 0000000000000001
[ 279.948345] R13: 0000000000409980 R14: 000000000047e538 R15: 0000000000485400
[ 279.949690] </TASK>
[ 279.950706] Allocated by task 2960:
[ 279.951471] kasan_save_stack+0x1e/0x40
[ 279.952338] kasan_set_track+0x21/0x30
[ 279.953165] __kasan_kmalloc+0x77/0x90
[ 279.954006] flow_block_cb_setup_simple+0x3dd/0x7c0
[ 279.955001] tcf_block_offload_cmd.isra.0+0x189/0x2d0
[ 279.956020] tcf_block_get_ext+0x61c/0x1200
[ 279.956881] ingress_init+0x112/0x1c0 [sch_ingress]
[ 279.957873] qdisc_create+0x401/0xea0
[ 279.958656] tc_modify_qdisc+0x6f7/0x16d0
[ 279.959506] rtnetlink_rcv_msg+0x5fe/0x9d0
[ 279.960392] netlink_rcv_skb+0x12c/0x360
[ 279.961216] netlink_unicast+0x553/0x790
[ 279.962044] netlink_sendmsg+0x7a1/0xcb0
[ 279.962906] sock_sendmsg+0xc5/0x190
[ 279.963702] ____sys_sendmsg+0x535/0x6b0
[ 279.964534] ___sys_sendmsg+0xeb/0x170
[ 279.965343] __sys_sendmsg+0xb5/0x140
[ 279.966132] do_syscall_64+0x3d/0x90
[ 279.966908] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 279.968407] Freed by task 2960:
[ 279.969114] kasan_save_stack+0x1e/0x40
[ 279.969929] kasan_set_track+0x21/0x30
[ 279.970729] kasan_save_free_info+0x2a/0x40
[ 279.971603] ____kasan_slab_free+0x11a/0x1b0
[ 279.972483] __kmem_cache_free+0x14d/0x280
[ 279.973337] tcf_block_setup+0x29d/0x6b0
[ 279.974173] tcf_block_offload_cmd.isra.0+0x226/0x2d0
[ 279.975186] tcf_block_get_ext+0x61c/0x1200
[ 279.976080] ingress_init+0x112/0x1c0 [sch_ingress]
[ 279.977065] qdisc_create+0x401/0xea0
[ 279.977857] tc_modify_qdisc+0x6f7/0x16d0
[ 279.978695] rtnetlink_rcv_msg+0x5fe/0x9d0
[ 279.979562] netlink_rcv_skb+0x12c/0x360
[ 279.980388] netlink_unicast+0x553/0x790
[ 279.981214] netlink_sendmsg+0x7a1/0xcb0
[ 279.982043] sock_sendmsg+0xc5/0x190
[ 279.982827] ____sys_sendmsg+0x535/0x6b0
[ 279.983703] ___sys_sendmsg+0xeb/0x170
[ 279.984510] __sys_sendmsg+0xb5/0x140
[ 279.985298] do_syscall_64+0x3d/0x90
[ 279.986076] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 279.987532] The buggy address belongs to the object at ffff888147e2bf00
which belongs to the cache kmalloc-192 of size 192
[ 279.989747] The buggy address is located 32 bytes inside of
freed 192-byte region [ffff888147e2bf00, ffff888147e2bfc0)
[ 279.992367] The buggy address belongs to the physical page:
[ 279.993430] page:00000000550f405c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147e2a
[ 279.995182] head:00000000550f405c order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[ 279.996713] anon flags: 0x200000000010200(slab|head|node=0|zone=2)
[ 279.997878] raw: 0200000000010200 ffff888100042a00 0000000000000000 dead000000000001
[ 279.999384] raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
[ 280.000894] page dumped because: kasan: bad access detected
[ 280.002386] Memory state around the buggy address:
[ 280.003338] ffff888147e2be00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 280.004781] ffff888147e2be80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[ 280.006224] >ffff888147e2bf00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 280.007700] ^
[ 280.008592] ffff888147e2bf80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[ 280.010035] ffff888147e2c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 280.011564] ==================================================================
The Linux kernel CVE team has assigned CVE-2023-54193 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.3 with commit 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 and fixed in 5.4.243 with commit cc5fe387c6294d0471cb7ed064efac97fac65ccc
Issue introduced in 5.3 with commit 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 and fixed in 5.10.180 with commit 7311c8be3755611bf6edea4dfbeb190b4bdd489f
Issue introduced in 5.3 with commit 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 and fixed in 5.15.112 with commit cb145932fcf6814e7e95e467eb70e7849a845ae9
Issue introduced in 5.3 with commit 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 and fixed in 6.1.29 with commit 55866fe3fded3ce94ac3fc1bb3dfce654282f483
Issue introduced in 5.3 with commit 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 and fixed in 6.2.16 with commit 26aec72429a05e917d574eca0efc5306c63a8862
Issue introduced in 5.3 with commit 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 and fixed in 6.3.3 with commit 7b7a74ed303d532fb73ae4b1697f16a0fea89cd0
Issue introduced in 5.3 with commit 59094b1e5094c7e50a3d2912202fd30b6a1dadf8 and fixed in 6.4 with commit da94a7781fc3c92e7df7832bc2746f4d39bc624e
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2023-54193
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
net/sched/cls_api.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/cc5fe387c6294d0471cb7ed064efac97fac65ccc
https://git.kernel.org/stable/c/7311c8be3755611bf6edea4dfbeb190b4bdd489f
https://git.kernel.org/stable/c/cb145932fcf6814e7e95e467eb70e7849a845ae9
https://git.kernel.org/stable/c/55866fe3fded3ce94ac3fc1bb3dfce654282f483
https://git.kernel.org/stable/c/26aec72429a05e917d574eca0efc5306c63a8862
https://git.kernel.org/stable/c/7b7a74ed303d532fb73ae4b1697f16a0fea89cd0
https://git.kernel.org/stable/c/da94a7781fc3c92e7df7832bc2746f4d39bc624e
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