CVE-2022-50054

Published Jun 18, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: iavf: Fix NULL pointer dereference in iavf_get_link_ksettings Fix possible NULL pointer dereference, due to freeing of adapter->vf_res in iavf_init_get_resources. Previous commit introduced a regression, where receiving IAVF_ERR_ADMIN_QUEUE_NO_WORK from iavf_get_vf_config would free adapter->vf_res. However, netdev is still registered, so ethtool_ops can be called. Calling iavf_get_link_ksettings with no vf_res, will result with: [ 9385.242676] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 9385.242683] #PF: supervisor read access in kernel mode [ 9385.242686] #PF: error_code(0x0000) - not-present page [ 9385.242690] PGD 0 P4D 0 [ 9385.242696] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [ 9385.242701] CPU: 6 PID: 3217 Comm: pmdalinux Kdump: loaded Tainted: G S E 5.18.0-04958-ga54ce3703613-dirty #1 [ 9385.242708] Hardware name: Dell Inc. PowerEdge R730/0WCJNT, BIOS 2.11.0 11/02/2019 [ 9385.242710] RIP: 0010:iavf_get_link_ksettings+0x29/0xd0 [iavf] [ 9385.242745] Code: 00 0f 1f 44 00 00 b8 01 ef ff ff 48 c7 46 30 00 00 00 00 48 c7 46 38 00 00 00 00 c6 46 0b 00 66 89 46 08 48 8b 87 68 0e 00 00 <f6> 40 08 80 75 50 8b 87 5c 0e 00 00 83 f8 08 74 7a 76 1d 83 f8 20 [ 9385.242749] RSP: 0018:ffffc0560ec7fbd0 EFLAGS: 00010246 [ 9385.242755] RAX: 0000000000000000 RBX: ffffc0560ec7fc08 RCX: 0000000000000000 [ 9385.242759] RDX: ffffffffc0ad4550 RSI: ffffc0560ec7fc08 RDI: ffffa0fc66674000 [ 9385.242762] RBP: 00007ffd1fb2bf50 R08: b6a2d54b892363ee R09: ffffa101dc14fb00 [ 9385.242765] R10: 0000000000000000 R11: 0000000000000004 R12: ffffa0fc66674000 [ 9385.242768] R13: 0000000000000000 R14: ffffa0fc66674000 R15: 00000000ffffffa1 [ 9385.242771] FS: 00007f93711a2980(0000) GS:ffffa0fad72c0000(0000) knlGS:0000000000000000 [ 9385.242775] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9385.242778] CR2: 0000000000000008 CR3: 0000000a8e61c003 CR4: 00000000003706e0 [ 9385.242781] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 9385.242784] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 9385.242787] Call Trace: [ 9385.242791] <TASK> [ 9385.242793] ethtool_get_settings+0x71/0x1a0 [ 9385.242814] __dev_ethtool+0x426/0x2f40 [ 9385.242823] ? slab_post_alloc_hook+0x4f/0x280 [ 9385.242836] ? kmem_cache_alloc_trace+0x15d/0x2f0 [ 9385.242841] ? dev_ethtool+0x59/0x170 [ 9385.242848] dev_ethtool+0xa7/0x170 [ 9385.242856] dev_ioctl+0xc3/0x520 [ 9385.242866] sock_do_ioctl+0xa0/0xe0 [ 9385.242877] sock_ioctl+0x22f/0x320 [ 9385.242885] __x64_sys_ioctl+0x84/0xc0 [ 9385.242896] do_syscall_64+0x3a/0x80 [ 9385.242904] entry_SYSCALL_64_after_hwframe+0x46/0xb0 [ 9385.242918] RIP: 0033:0x7f93702396db [ 9385.242923] Code: 73 01 c3 48 8b 0d ad 57 38 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 7d 57 38 00 f7 d8 64 89 01 48 [ 9385.242927] RSP: 002b:00007ffd1fb2bf18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 9385.242932] RAX: ffffffffffffffda RBX: 000055671b1d2fe0 RCX: 00007f93702396db [ 9385.242935] RDX: 00007ffd1fb2bf20 RSI: 0000000000008946 RDI: 0000000000000007 [ 9385.242937] RBP: 00007ffd1fb2bf20 R08: 0000000000000003 R09: 0030763066307330 [ 9385.242940] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd1fb2bf80 [ 9385.242942] R13: 0000000000000007 R14: 0000556719f6de90 R15: 00007ffd1fb2c1b0 [ 9385.242948] </TASK> [ 9385.242949] Modules linked in: iavf(E) xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nft_compat nf_nat_tftp nft_objref nf_conntrack_tftp bridge stp llc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables rfkill nfnetlink vfat fat irdma ib_uverbs ib_core intel_rapl_msr intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretem ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)•CVE-2026-98163