CVE-2024-53088

In the Linux kernel, the following vulnerability has been resolved:

i40e: fix race condition by adding filters intermediate sync state

Fix a race condition in the i40e driver that leads to MAC/VLAN filters becoming corrupted and leaking. Address the issue that occurs under heavy load when multiple threads are concurrently modifying MAC/VLAN filters by setting mac and port VLAN.

1. Thread T0 allocates a filter in i40e_add_filter() within i40e_ndo_set_vf_port_vlan().
2. Thread T1 concurrently frees the filter in __i40e_del_filter() within i40e_ndo_set_vf_mac().
3. Subsequently, i40e_service_task() calls i40e_sync_vsi_filters(), which refers to the already freed filter memory, causing corruption.

Reproduction steps:

1. Spawn multiple VFs.
2. Apply a concurrent heavy load by running parallel operations to change MAC addresses on the VFs and change port VLANs on the host.
3. Observe errors in dmesg: Error I40E_AQ_RC_ENOSPC adding RX filters on VF XX, please set promiscuous on manually for VF XX.

Exact code for stable reproduction Intel cant open-source now.

The fix involves implementing a new intermediate filter state, I40E_FILTER_NEW_SYNC, for the time when a filter is on a tmp_add_list. These filters cannot be deleted from the hash list directly but must be removed using the full process.

Weakness

The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.

Affected Software

Extended Description

This can have security implications when the expected synchronization is in security-critical code, such as recording whether a user is authenticated or modifying important state information that should not be influenced by an outsider. A race condition occurs within concurrent environments, and is effectively a property of a code sequence. Depending on the context, a code sequence may be in the form of a function call, a small number of instructions, a series of program invocations, etc. A race condition violates these properties, which are closely related:

A race condition exists when an “interfering code sequence” can still access the shared resource, violating exclusivity. Programmers may assume that certain code sequences execute too quickly to be affected by an interfering code sequence; when they are not, this violates atomicity. For example, the single “x++” statement may appear atomic at the code layer, but it is actually non-atomic at the instruction layer, since it involves a read (the original value of x), followed by a computation (x+1), followed by a write (save the result to x). The interfering code sequence could be “trusted” or “untrusted.” A trusted interfering code sequence occurs within the product; it cannot be modified by the attacker, and it can only be invoked indirectly. An untrusted interfering code sequence can be authored directly by the attacker, and typically it is external to the vulnerable product.

Potential Mitigations

• Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring.
• Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• https://git.kernel.org/stable/c/262dc6ea5f1eb18c4d08ad83d51222d0dd0dd42a
• https://git.kernel.org/stable/c/6e046f4937474bc1b9fa980c1ad8f3253fc638f6
• https://git.kernel.org/stable/c/7ad3fb3bfd43feb4e15c81dffd23ac4e55742791
• https://git.kernel.org/stable/c/bf5f837d9fd27d32fb76df0a108babcaf4446ff1
• https://git.kernel.org/stable/c/f30490e9695ef7da3d0899c6a0293cc7cd373567