CVE-2023-53581
Description
A race condition was found in the Linux kernel Mellanox mlx5 network driver's traffic control offload flow management. A local user with privileges to configure traffic control flower filters can trigger concurrent flow deletion operations where the NOT_READY flag is checked before acquiring the necessary lock, allowing a workqueue task to concurrently remove the flow from the unready_flows list, which causes double-removal from the linked list and results in list corruption leading to denial of service via kernel crash or potentially memory corruption.
Statement
The issue arises because of incorrect lock ordering in the flow deletion path. When mlx5e_tc_del_fdb_flow() processes a flow deletion, it first checks the NOT_READY flag to determine if the flow is on the unready_flows list, then acquires the uplink_priv->unready_flows_lock mutex to remove it. However, between the flag check and lock acquisition, a workqueue task can acquire the same lock and remove the flow from the list. When the original thread then acquires the lock and attempts list removal, it performs a double-removal on an entry that is no longer in the list. This corrupts the linked list pointers, causing subsequent list operations to access freed memory containing poison values (0xdead000000000100). The race window is narrow, requiring the workqueue to execute between the flag check and lock acquisition. While this reliably causes kernel crashes when the race occurs, the underlying list corruption represents a memory safety violation that could potentially be leveraged for more sophisticated attacks with careful timing and heap manipulation.
Mitigation
To mitigate this issue, prevent the mlx5_core module from loading. See https://access.redhat.com/solutions/41278 for instructions on blacklisting kernel modules.
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 | 5.5 | 4.7 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
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