CVE-2022-50736
Description
A flaw was identified in the Linux kernel RDMA (siw) implementation where an undefined opcode value could be used during immediate work request flushing while in an error state. The send queue element opcode was not correctly set, which could lead to an out-of-bounds access when mapping between the SoftiWARP internal representation and the RDMA core representation in work completion generation. On some test configurations (e.g., NFSoRDMA testing), this resulted in a KASAN BUG report of type global-out-of-bounds. Additionally, a malicious local user with access to a memory-mapped completion queue (CQ) could supply undefined values for completion queue element status or opcode, leading to similar out-of-bounds array access.
Mitigation
To mitigate this issue, prevent the `siw` kernel module from loading. Create a file named `/etc/modprobe.d/disable-siw.conf` with the following content:
`install siw /bin/true`
After creating the file, regenerate the initramfs and reboot the system for the changes to take effect. This mitigation may impact functionality that relies on the Shared-memory InfiniBand Work (siw) component.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5 | N/A | 7.1 |
| Attack Vector | Network | N/A | Local |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | High |
| Integrity Impact | Low | N/A | None |
| Availability Impact | Low | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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