Описание
In the Linux kernel, the following vulnerability has been resolved:
drop_monitor: fix out-of-bounds write in reset_per_cpu_data()
In reset_per_cpu_data(), al is computed as:
al = sizeof(struct net_dm_alert_msg);
al += dm_hit_limit * sizeof(struct net_dm_drop_point);
al += sizeof(struct nlattr);
skb = genlmsg_new(al, GFP_KERNEL);
...
nla = nla_reserve(skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg));
...
msg = nla_data(nla);
memset(msg, 0, al);
Because al includes sizeof(struct nlattr) (the 4-byte attribute header),
genlmsg_new() allocates al bytes of tailroom starting at nla.
However, msg points to nla_data(nla), which is located
sizeof(struct nlattr) bytes past nla. Calling memset(msg, 0, al)
therefore writes al bytes starting from msg, exceeding the allocated
buffer by sizeof(struct nlattr) (4 bytes) and corrupting
skb_shared_info.
Fix this by letting al represent only the payload length, allocating
the skb with genlmsg_new(nla_total_size(al), GFP_KERNEL), and zeroing
al bytes from msg.
A flaw was found in the Linux kernel's drop_monitor subsystem. An incorrect buffer size calculation during per-CPU data resets leads to an out-of-bounds write when clearing memory. A local user could exploit this vulnerability to corrupt kernel memory, resulting in a system crash and Denial of Service (DoS).
Отчет
A moderate out-of-bounds write flaw was found in the Linux kernel's drop_monitor subsystem. It affects the kernel and kernel-rt components in Red Hat Enterprise Linux 7, 8, 9 and 10, the kernel and kernel-ivos-qualcomm components in Red Hat In-Vehicle OS 2, and the RHEL CoreOS 8 and RHEL CoreOS 9 layers of OpenShift Container Platform 4. When drop monitoring is active and per-CPU statistics are reset, an incorrect buffer size calculation causes memset() to write four bytes past the end of the allocated socket buffer, corrupting the skb_shared_info structure. A local user who can trigger packet drops on a system where drop monitoring is active could exploit this to corrupt kernel memory and crash the system, resulting in a denial of service; the flaw does not compromise confidentiality or integrity. Red Hat Enterprise Linux 6 is out of support scope and will not receive a fix. For the affected products, the fix has been deferred to a future scheduled update because the flaw is rated moderate impact and the residual risk is limited to local denial of service by an authenticated local user with access to a system running active drop monitoring.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not 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 | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: drop_monitor: fix out-of-bounds write in reset_per_cpu_data() In reset_per_cpu_data(), al is computed as: al = sizeof(struct net_dm_alert_msg); al += dm_hit_limit * sizeof(struct net_dm_drop_point); al += sizeof(struct nlattr); skb = genlmsg_new(al, GFP_KERNEL); ... nla = nla_reserve(skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg)); ... msg = nla_data(nla); memset(msg, 0, al); Because al includes sizeof(struct nlattr) (the 4-byte attribute header), genlmsg_new() allocates al bytes of tailroom starting at nla. However, msg points to nla_data(nla), which is located sizeof(struct nlattr) bytes past nla. Calling memset(msg, 0, al) therefore writes al bytes starting from msg, exceeding the allocated buffer by sizeof(struct nlattr) (4 bytes) and corrupting skb_shared_info. Fix this by letting al represent only the payload length, allocating the skb with genlmsg_new(nla_total_size(al), GFP_KERNEL), and zeroing al bytes fr...
In the Linux kernel, the following vulnerability has been resolved: drop_monitor: fix out-of-bounds write in reset_per_cpu_data() In reset_per_cpu_data(), al is computed as: al = sizeof(struct net_dm_alert_msg); al += dm_hit_limit * sizeof(struct net_dm_drop_point); al += sizeof(struct nlattr); skb = genlmsg_new(al, GFP_KERNEL); ... nla = nla_reserve(skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg)); ... msg = nla_data(nla); memset(msg, 0, al); Because al includes sizeof(struct nlattr) (the 4-byte attribute header), genlmsg_new() allocates al bytes of tailroom starting at nla. However, msg points to nla_data(nla), which is located sizeof(struct nlattr) bytes past nla. Calling memset(msg, 0, al) therefore writes al bytes starting from msg, exceeding the allocated buffer by sizeof(struct nlattr) (4 bytes) and corrupting skb_shared_info. Fix this by letting al represent only the payload length, allocating the skb with genlmsg_new(nla_total_size(al
drop_monitor: fix out-of-bounds write in reset_per_cpu_data()
In the Linux kernel, the following vulnerability has been resolved: d ...
In the Linux kernel, the following vulnerability has been resolved: drop_monitor: fix out-of-bounds write in reset_per_cpu_data() In reset_per_cpu_data(), al is computed as: al = sizeof(struct net_dm_alert_msg); al += dm_hit_limit * sizeof(struct net_dm_drop_point); al += sizeof(struct nlattr); skb = genlmsg_new(al, GFP_KERNEL); ... nla = nla_reserve(skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg)); ... msg = nla_data(nla); memset(msg, 0, al); Because al includes sizeof(struct nlattr) (the 4-byte attribute header), genlmsg_new() allocates al bytes of tailroom starting at nla. However, msg points to nla_data(nla), which is located sizeof(struct nlattr) bytes past nla. Calling memset(msg, 0, al) therefore writes al bytes starting from msg, exceeding the allocated buffer by sizeof(struct nlattr) (4 bytes) and corrupting skb_shared_info. Fix this by letting al represent only the payload length, allocating the skb with genlmsg_new(nla_total_size...
EPSS
5.5 Medium
CVSS3