Re: [PATCH net v3] bridge: cfm: reject invalid CCM interval at configuration time

[Ido Schimmel <idosch@nvidia.com>]

On Sat, Jun 06, 2026 at 02:58:48PM -0700, Xiang Mei wrote:
> ccm_tx_work_expired() re-arms itself via queue_delayed_work() using
> the configured exp_interval converted by interval_to_us(). When
> exp_interval is BR_CFM_CCM_INTERVAL_NONE or out of range,
> interval_to_us() returns 0, causing the worker to fire immediately in
> a tight loop that allocates skbs until OOM.
> 
> Fix this by validating exp_interval at configuration time:
> 
>  - Constrain IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL to the valid range
>    [BR_CFM_CCM_INTERVAL_3_3_MS, BR_CFM_CCM_INTERVAL_10_MIN] in the
>    netlink policy so userspace cannot set an invalid value.
> 
>  - Reject starting CCM TX in br_cfm_cc_ccm_tx() when exp_interval has
>    not yet been configured (defaults to 0 from kzalloc).
> 
> Fixes: 2be665c3940d ("bridge: cfm: Netlink SET configuration Interface.")
> Reported-by: Weiming Shi <bestswngs@gmail.com>
> Suggested-by: Ido Schimmel <idosch@nvidia.com>
> Signed-off-by: Xiang Mei <xmei5@asu.edu>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

Nit: I don't think that the Suggested-by is appropriate here since I
merely had minor comments on the previous version.