Описание
In the Linux kernel, the following vulnerability has been resolved:
Input: zero ff_effect before compat copy in input_ff_effect_from_user
In the compat path input_ff_effect_from_user() aliases the caller's
native struct ff_effect with the smaller struct ff_effect_compat and
copies only the compat sized prefix:
compat_effect = (struct ff_effect_compat *)effect;
if (copy_from_user(compat_effect, buffer,
sizeof(struct ff_effect_compat)))
The tail of the native structure is never written. Callers pass an
uninitialized on-stack object, for example evdev_do_ioctl() for
EVIOCSFF, so those bytes keep their previous stack contents.
input_ff_upload() then stores the full native structure in
ff->effects[id], from where a uinput based force feedback daemon can
read it back via UI_BEGIN_FF_UPLOAD, disclosing kernel stack memory to
userspace.
Zero the effect before the compat copy.
A flaw was found in the Linux kernel's input subsystem. When handling 32-bit compatibility requests for force feedback input effects, the kernel fails to properly initialize memory buffers before copying data from user space. A local user can exploit this vulnerability to read uninitialized kernel stack data, leading to information disclosure of potentially sensitive system memory.
Отчет
A kernel stack information disclosure occurs in input_ff_effect_from_user() because the 32-bit compat path copies only struct ff_effect_compat into a larger native struct ff_effect. The remaining bytes retain previous kernel stack contents and input_ff_upload() stores the complete native structure in the force feedback effect table. A uinput based force feedback daemon can later receive these bytes through UI_BEGIN_FF_UPLOAD. For the CVSS the PR:L value is used because a local user or process must access the relevant input device and trigger the compat force feedback upload path. The base score uses AC:H and C:L because exploitation depends on a 32-bit compat caller, a suitable force feedback device, and a cooperating uinput based daemon, while the directly exposed data is limited to the uninitialized structure tail. The paranoid score uses AC:L and C:H when this environment is already available because repeated kernel stack disclosures may expose addresses or other sensitive values and can weaken protections such as KASLR. The issue is not network reachable. It does not provide a direct write primitive or a demonstrated standalone privilege escalation path, but the disclosed kernel data may assist exploitation of another vulnerability.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 8 | kernel | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9 | kernel | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Affected |
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Дополнительная информация
Статус:
3.3 Low
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: Input: zero ff_effect before compat copy in input_ff_effect_from_user In the compat path input_ff_effect_from_user() aliases the caller's native struct ff_effect with the smaller struct ff_effect_compat and copies only the compat sized prefix: compat_effect = (struct ff_effect_compat *)effect; if (copy_from_user(compat_effect, buffer, sizeof(struct ff_effect_compat))) The tail of the native structure is never written. Callers pass an uninitialized on-stack object, for example evdev_do_ioctl() for EVIOCSFF, so those bytes keep their previous stack contents. input_ff_upload() then stores the full native structure in ff->effects[id], from where a uinput based force feedback daemon can read it back via UI_BEGIN_FF_UPLOAD, disclosing kernel stack memory to userspace. Zero the effect before the compat copy.
In the Linux kernel, the following vulnerability has been resolved: Input: zero ff_effect before compat copy in input_ff_effect_from_user In the compat path input_ff_effect_from_user() aliases the caller's native struct ff_effect with the smaller struct ff_effect_compat and copies only the compat sized prefix: compat_effect = (struct ff_effect_compat *)effect; if (copy_from_user(compat_effect, buffer, sizeof(struct ff_effect_compat))) The tail of the native structure is never written. Callers pass an uninitialized on-stack object, for example evdev_do_ioctl() for EVIOCSFF, so those bytes keep their previous stack contents. input_ff_upload() then stores the full native structure in ff->effects[id], from where a uinput based force feedback daemon can read it back via UI_BEGIN_FF_UPLOAD, disclosing kernel stack memory to userspace. Zero the effect before the compat copy.
Input: zero ff_effect before compat copy in input_ff_effect_from_user
In the Linux kernel, the following vulnerability has been resolved: I ...
In the Linux kernel, the following vulnerability has been resolved: Input: zero ff_effect before compat copy in input_ff_effect_from_user In the compat path input_ff_effect_from_user() aliases the caller's native struct ff_effect with the smaller struct ff_effect_compat and copies only the compat sized prefix: compat_effect = (struct ff_effect_compat *)effect; if (copy_from_user(compat_effect, buffer, sizeof(struct ff_effect_compat))) The tail of the native structure is never written. Callers pass an uninitialized on-stack object, for example evdev_do_ioctl() for EVIOCSFF, so those bytes keep their previous stack contents. input_ff_upload() then stores the full native structure in ff->effects[id], from where a uinput based force feedback daemon can read it back via UI_BEGIN_FF_UPLOAD, disclosing kernel stack memory to userspace. Zero the effect before the compat copy.
3.3 Low
CVSS3