Re: [PATCH net 1/2] ethtool: cmis_cdb: use correct rpl size in ethtool_cmis_module_poll()

[Ido Schimmel <idosch@idosch.org>]

On Wed, Apr 02, 2025 at 11:31:22AM -0700, Michael Chan wrote:
> From: Damodharam Ammepalli <damodharam.ammepalli@broadcom.com>
> 
> rpl is passed as a pointer to ethtool_cmis_module_poll(), so the correct
> size of rpl is sizeof(*rpl) which should be just 1 byte.  Using the
> pointer size instead can cause stack corruption:
> 
> Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ethtool_cmis_wait_for_cond+0xf4/0x100
> CPU: 72 UID: 0 PID: 4440 Comm: kworker/72:2 Kdump: loaded Tainted: G           OE      6.11.0 #24
> Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
> Hardware name: Dell Inc. PowerEdge R760/04GWWM, BIOS 1.6.6 09/20/2023
> Workqueue: events module_flash_fw_work
> Call Trace:
>  <TASK>
>  panic+0x339/0x360
>  ? ethtool_cmis_wait_for_cond+0xf4/0x100
>  ? __pfx_status_success+0x10/0x10
>  ? __pfx_status_fail+0x10/0x10
>  __stack_chk_fail+0x10/0x10
>  ethtool_cmis_wait_for_cond+0xf4/0x100
>  ethtool_cmis_cdb_execute_cmd+0x1fc/0x330
>  ? __pfx_status_fail+0x10/0x10
>  cmis_cdb_module_features_get+0x6d/0xd0
>  ethtool_cmis_cdb_init+0x8a/0xd0
>  ethtool_cmis_fw_update+0x46/0x1d0
>  module_flash_fw_work+0x17/0xa0
>  process_one_work+0x179/0x390
>  worker_thread+0x239/0x340
>  ? __pfx_worker_thread+0x10/0x10
>  kthread+0xcc/0x100
>  ? __pfx_kthread+0x10/0x10
>  ret_from_fork+0x2d/0x50
>  ? __pfx_kthread+0x10/0x10
>  ret_from_fork_asm+0x1a/0x30
>  </TASK>
> 
> Fixes: a39c84d79625 ("ethtool: cmis_cdb: Add a layer for supporting CDB commands)
> Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
> Signed-off-by: Damodharam Ammepalli <damodharam.ammepalli@broadcom.com>
> Signed-off-by: Michael Chan <michael.chan@broadcom.com>

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