Описание
Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. When building a UFO packet with MSG_MORE __ip_append_data() calls ip_ufo_append_data() to append. However in between two send() calls, the append path can be switched from UFO to non-UFO one, which leads to a memory corruption. In case UFO packet lengths exceeds MTU, copy = maxfraglen - skb->len becomes negative on the non-UFO path and the branch to allocate new skb is taken. This triggers fragmentation and computation of fraggap = skb_prev->len - maxfraglen. Fraggap can exceed MTU, causing copy = datalen - transhdrlen - fraggap to become negative. Subsequently skb_copy_and_csum_bits() writes out-of-bounds. A similar issue is present in IPv6 code. The bug was introduced in e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") on Oct 18 2005.
An exploitable memory corruption flaw was found in the Linux kernel. The append path can be erroneously switched from UFO to non-UFO in ip_ufo_append_data() when building an UFO packet with MSG_MORE option. If unprivileged user namespaces are available, this flaw can be exploited to gain root privileges.
Отчет
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 5,6, 7 and MRG-2. Future Linux kernel updates for the respective releases may address this issue.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 7 | kernel-alt | Affected | ||
| Red Hat Enterprise Linux 5.9 Long Life | kernel | Fixed | RHSA-2019:1932 | 29.07.2019 |
| Red Hat Enterprise Linux 5 Extended Lifecycle Support | kernel | Fixed | RHSA-2019:1931 | 29.07.2019 |
| Red Hat Enterprise Linux 6 | kernel | Fixed | RHSA-2017:3200 | 14.11.2017 |
| Red Hat Enterprise Linux 7 | kernel-rt | Fixed | RHSA-2017:2931 | 19.10.2017 |
| Red Hat Enterprise Linux 7 | kernel | Fixed | RHSA-2017:2930 | 19.10.2017 |
| Red Hat Enterprise Linux 7.3 Advanced Update Support | kernel | Fixed | RHSA-2019:4159 | 10.12.2019 |
| Red Hat Enterprise Linux 7.3 Telco Extended Update Support | kernel | Fixed | RHSA-2019:4159 | 10.12.2019 |
| Red Hat Enterprise Linux 7.3 Update Services for SAP Solutions | kernel | Fixed | RHSA-2019:4159 | 10.12.2019 |
| Red Hat Enterprise MRG 2 | kernel-rt | Fixed | RHSA-2017:2918 | 19.10.2017 |
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Дополнительная информация
Статус:
EPSS
7 High
CVSS3
Связанные уязвимости
Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. When building a UFO packet with MSG_MORE __ip_append_data() calls ip_ufo_append_data() to append. However in between two send() calls, the append path can be switched from UFO to non-UFO one, which leads to a memory corruption. In case UFO packet lengths exceeds MTU, copy = maxfraglen - skb->len becomes negative on the non-UFO path and the branch to allocate new skb is taken. This triggers fragmentation and computation of fraggap = skb_prev->len - maxfraglen. Fraggap can exceed MTU, causing copy = datalen - transhdrlen - fraggap to become negative. Subsequently skb_copy_and_csum_bits() writes out-of-bounds. A similar issue is present in IPv6 code. The bug was introduced in e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") on Oct 18 2005.
Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. When building a UFO packet with MSG_MORE __ip_append_data() calls ip_ufo_append_data() to append. However in between two send() calls, the append path can be switched from UFO to non-UFO one, which leads to a memory corruption. In case UFO packet lengths exceeds MTU, copy = maxfraglen - skb->len becomes negative on the non-UFO path and the branch to allocate new skb is taken. This triggers fragmentation and computation of fraggap = skb_prev->len - maxfraglen. Fraggap can exceed MTU, causing copy = datalen - transhdrlen - fraggap to become negative. Subsequently skb_copy_and_csum_bits() writes out-of-bounds. A similar issue is present in IPv6 code. The bug was introduced in e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") on Oct 18 2005.
Linux kernel: Exploitable memory corruption due to UFO to non-UFO path ...
Security update for Linux Kernel Live Patch 21 for SLE 12
Security update for Linux Kernel Live Patch 19 for SLE 12
EPSS
7 High
CVSS3