CVE-2023-53199

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

wifi: ath9k: hif_usb: clean up skbs if ath9k_hif_usb_rx_stream() fails

Syzkaller detected a memory leak of skbs in ath9k_hif_usb_rx_stream(). While processing skbs in ath9k_hif_usb_rx_stream(), the already allocated skbs in skb_pool are not freed if ath9k_hif_usb_rx_stream() fails. If we have an incorrect pkt_len or pkt_tag, the input skb is considered invalid and dropped. All the associated packets already in skb_pool should be dropped and freed. Added a comment describing this issue.

The patch also makes remain_skb NULL after being processed so that it cannot be referenced after potential free. The initialization of hif_dev fields which are associated with remain_skb (rx_remain_len, rx_transfer_len and rx_pad_len) is moved after a new remain_skb is allocated.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Weakness

The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.
• Use resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available. However, these functions are not available on all operating systems.
• When the current levels get close to the maximum that is defined for the application (see CWE-770), then limit the allocation of further resources to privileged users; alternately, begin releasing resources for less-privileged users. While this mitigation may protect the system from attack, it will not necessarily stop attackers from adversely impacting other users.
• Ensure that the application performs the appropriate error checks and error handling in case resources become unavailable (CWE-703).

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/469.html

References

• https://git.kernel.org/stable/c/0af54343a76263a12dbae7fafb64eb47c4a6ad38
• https://git.kernel.org/stable/c/3fc6401fafde11712a83089fa2cc874cfd10e2cd
• https://git.kernel.org/stable/c/61490d2710277e8a55009b7682456ae22f8087cf
• https://git.kernel.org/stable/c/9acdec72787af1bc8ed92711b52118c8e3e638a2
• https://git.kernel.org/stable/c/c766e37fccd5a5c5059be7efcd9618bf8a2c17c3
• https://git.kernel.org/stable/c/cd8316767099920a5d41feed1afab0c482a43e9f
• https://git.kernel.org/stable/c/f26dd69f61eff2eedf5df2d199bdd23108309947