CVE-2024-49938

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

wifi: ath9k_htc: Use __skb_set_length() for resetting urb before resubmit

Syzbot points out that skb_trim() has a sanity check on the existing length of the skb, which can be uninitialised in some error paths. The intent here is clearly just to reset the length to zero before resubmitting, so switch to calling __skb_set_length(skb, 0) directly. In addition, __skb_set_length() already contains a call to skb_reset_tail_pointer(), so remove the redundant call.

The syzbot report came from ath9k_hif_usb_reg_in_cb(), but theres a similar usage of skb_trim() in ath9k_hif_usb_rx_cb(), change both while were at it.

Weakness

The product accesses or uses a pointer that has not been initialized.

Affected Software

Extended Description

If the pointer contains an uninitialized value, then the value might not point to a valid memory location. This could cause the product to read from or write to unexpected memory locations, leading to a denial of service. If the uninitialized pointer is used as a function call, then arbitrary functions could be invoked. If an attacker can influence the portion of uninitialized memory that is contained in the pointer, this weakness could be leveraged to execute code or perform other attacks. Depending on memory layout, associated memory management behaviors, and product operation, the attacker might be able to influence the contents of the uninitialized pointer, thus gaining more fine-grained control of the memory location to be accessed.

References

• https://git.kernel.org/stable/c/012ae530afa0785102360de452745d33c99a321b
• https://git.kernel.org/stable/c/2c230210ec0ae6ed08306ac70dc21c24b817bb95
• https://git.kernel.org/stable/c/6a875220670475d9247e576c15dc29823100a4e4
• https://git.kernel.org/stable/c/94745807f3ebd379f23865e6dab196f220664179
• https://git.kernel.org/stable/c/a9f4e28e8adaf0715bd4e01462af0a52ee46b01f
• https://git.kernel.org/stable/c/b02eb7c86ff2ef1411c3095ec8a52b13f68db04f
• https://git.kernel.org/stable/c/d1f2fbc6a769081503f6ffedbb5cd1ac497f0e77
• https://git.kernel.org/stable/c/e37e348835032d6940ec89308cc8996ded691d2d
• https://git.kernel.org/stable/c/e6b9bf32e0695e4f374674002de0527d2a6768eb