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

[Kalle Valo <kvalo@kernel.org>]

Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com> writes:

> 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.
>
> Add a check to ensure that link_id does not exceed the valid range of the
> vif->link_conf array. Log a warning and return -EINVAL if the check fails
> to prevent undefined behavior.
>
> Changelog:
>
> v2:
> 	- Updated the commit message as per the reviewer's suggestions
> 	- Clarified the description of the bug in the commit message
> 	- Added Fixes and Closes tags with relevant information
>
> Fixes: 90570ba4610 ("wifi: ath12k: do not return invalid link id for scan link")
> Closes: https://scan7.scan.coverity.com/#/project-view/52337/11354?selectedIssue=1602214
>
> Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
> ---

In wireless we prefer to have changelog after the '---' line so it's not
included in git. Not sure if Jeff can fix this during commit or not.

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