Описание
In the Linux kernel, the following vulnerability has been resolved:
Revert "net/smc: Introduce TCP ULP support"
This reverts commit d7cd421da9da2cc7b4d25b8537f66db5c8331c40.
As reported by Al Viro, the TCP ULP support for SMC is fundamentally
broken. The implementation attempts to convert an active TCP socket
into an SMC socket by modifying the underlying struct file, dentry,
and inode in-place, which violates core VFS invariants that assume
these structures are immutable for an open file, creating a risk of
use after free errors and general system instability.
Given the severity of this design flaw and the fact that cleaner
alternatives (e.g., LD_PRELOAD, BPF) exist for legacy application
transparency, the correct course of action is to remove this feature
entirely.
A flaw was found in the Linux kernel's TCP User-Level Protocol (ULP) support for SMC. This vulnerability arises when an active TCP socket is converted into an SMC socket, as the implementation attempts to modify core Virtual File System (VFS) structures in-place. This action violates fundamental VFS invariants, leading to a risk of use-after-free errors and general system instability.
Отчет
The SMC TCP ULP implementation attempted to convert an already open TCP socket into an SMC socket by modifying the underlying struct file, private_data, inode, and dentry state in place. This violates VFS lifetime and identity assumptions for open files and can create use-after-free conditions or general kernel instability when later close, fput, dput, or socket paths operate on stale or mismatched objects. For the CVSS the PR:L is used because a local unprivileged process may be able to create a TCP socket and request the smc TCP ULP on its own file descriptor when the feature is available. The issue is not directly network reachable because the dangerous operation is a local socket control operation rather than remote packet processing. Impact is at least local denial of service via kernel crash, and potentially it may allow confidentiality or integrity impact due to UAF style memory corruption and should be reviewed manually.
Меры по смягчению последствий
To mitigate this issue, prevent module smc from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not 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 |
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Дополнительная информация
Статус:
EPSS
7 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: Revert "net/smc: Introduce TCP ULP support" This reverts commit d7cd421da9da2cc7b4d25b8537f66db5c8331c40. As reported by Al Viro, the TCP ULP support for SMC is fundamentally broken. The implementation attempts to convert an active TCP socket into an SMC socket by modifying the underlying `struct file`, dentry, and inode in-place, which violates core VFS invariants that assume these structures are immutable for an open file, creating a risk of use after free errors and general system instability. Given the severity of this design flaw and the fact that cleaner alternatives (e.g., LD_PRELOAD, BPF) exist for legacy application transparency, the correct course of action is to remove this feature entirely.
In the Linux kernel, the following vulnerability has been resolved: Revert "net/smc: Introduce TCP ULP support" This reverts commit d7cd421da9da2cc7b4d25b8537f66db5c8331c40. As reported by Al Viro, the TCP ULP support for SMC is fundamentally broken. The implementation attempts to convert an active TCP socket into an SMC socket by modifying the underlying `struct file`, dentry, and inode in-place, which violates core VFS invariants that assume these structures are immutable for an open file, creating a risk of use after free errors and general system instability. Given the severity of this design flaw and the fact that cleaner alternatives (e.g., LD_PRELOAD, BPF) exist for legacy application transparency, the correct course of action is to remove this feature entirely.
In the Linux kernel, the following vulnerability has been resolved: R ...
In the Linux kernel, the following vulnerability has been resolved: Revert "net/smc: Introduce TCP ULP support" This reverts commit d7cd421da9da2cc7b4d25b8537f66db5c8331c40. As reported by Al Viro, the TCP ULP support for SMC is fundamentally broken. The implementation attempts to convert an active TCP socket into an SMC socket by modifying the underlying `struct file`, dentry, and inode in-place, which violates core VFS invariants that assume these structures are immutable for an open file, creating a risk of use after free errors and general system instability. Given the severity of this design flaw and the fact that cleaner alternatives (e.g., LD_PRELOAD, BPF) exist for legacy application transparency, the correct course of action is to remove this feature entirely.
EPSS
7 High
CVSS3