CVE-2009-0675

Published Feb 22, 2009

Last updated 6 months ago

Overview

Description
The skfp_ioctl function in drivers/net/skfp/skfddi.c in the Linux kernel before 2.6.28.6 permits SKFP_CLR_STATS requests only when the CAP_NET_ADMIN capability is absent, instead of when this capability is present, which allows local users to reset the driver statistics, related to an "inverted logic" issue.
Source
cve@mitre.org
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 2.0

Type
Primary
Base score
2.1
Impact score
2.9
Exploitability score
3.9
Vector string
AV:L/AC:L/Au:N/C:N/I:P/A:N

Weaknesses

nvd@nist.gov
CWE-264

Social media

Hype score
Not currently trending

Vendor comments

  • Red HatThis issue did not affect the version of Linux kernel as shipped with Red Hat Enterprise Linux 4 as the affected driver is not enabled in these kernels by default. The affected driver is enabled by default in Red Hat Enterprise Linux 2.1, 3, 5, and Red Hat Enterprise MRG. It was addressed in Red Hat Enterprise Linux 5 via https://rhn.redhat.com/errata/RHSA-2009-0326.html and Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2009-0360.html . As Red Hat Enterprise Linux 2.1 and 3 are now in Production 3 of their maintenance life-cycle, http://www.redhat.com/security/updates/errata, and this issue has been rated as having moderate impact, the fix for this issue is not currently planned to be included in the future updates.

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

References

Sources include official advisories and independent security research.