Re: [PATCH v2 wireless-next] wifi: ath12k: Fix out-of-bounds read in ath12k_mac_vdev_create

[Vasanthakumar Thiagarajan <quic_vthiagar@quicinc.com>]

On 12/7/2024 12:43 PM, Dheeraj Reddy Jonnalagadda wrote:
> Add a bounds check to ath12k_mac_vdev_create() to prevent an out-of-bounds
> read in the vif->link_conf array. The function uses link_id, derived from
> arvif->link_id, to index the array. When link_id equals 15, the index
> exceeds the bounds of the array, which contains only 15 elements.
> 
> This issue occurs in the following code branch:
> 
>      if (arvif->link_id == ATH12K_DEFAULT_SCAN_LINK && vif->valid_links)
>          link_id = ffs(vif->valid_links) - 1;
>      else
>          link_id = arvif->link_id;
> 
> When the first condition in the if statement is true and the second
> condition is false, it implies that arvif->link_id equals 15 and
> the else branch is taken, where link_id is set to 15, causing an
> out-of-bounds access when vif->link_conf array is read using link_id
> as index.

Practically this can not happen as ath12k_mac_assign_link_vif() which
retrieves the arvif by link_id before calling ath12k_mac_vdev_create()
sanitizes the link_id when there are no valid_links running for that
vif (!vif->valid_links).

Vasanth