Re: [PATCH] scsi: aacraid: Allocate cmd_priv with scsicmd

[Hannes Reinecke <hare@suse.de>]

On 1/28/23 01:04, Kees Cook wrote:
> The aac_priv() helper assumes that the private cmd area immediately
> follows struct scsi_cmnd. Allocate this space as part of scsicmd,
> else there is a risk of heap overflow. Seen with GCC 13:
> 
> ../drivers/scsi/aacraid/aachba.c: In function 'aac_probe_container':
> ../drivers/scsi/aacraid/aachba.c:841:26: warning: array subscript 16 is outside array bounds of 'void[392]' [-Warray-bounds=]
>    841 |         status = cmd_priv->status;
>        |                          ^~
> In file included from ../include/linux/resource_ext.h:11,
>                   from ../include/linux/pci.h:40,
>                   from ../drivers/scsi/aacraid/aachba.c:22:
> In function 'kmalloc',
>      inlined from 'kzalloc' at ../include/linux/slab.h:720:9,
>      inlined from 'aac_probe_container' at ../drivers/scsi/aacraid/aachba.c:821:30:
> ../include/linux/slab.h:580:24: note: at offset 392 into object of size 392 allocated by 'kmalloc_trace'
>    580 |                 return kmalloc_trace(
>        |                        ^~~~~~~~~~~~~~
>    581 |                                 kmalloc_caches[kmalloc_type(flags)][index],
>        |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    582 |                                 flags, size);
>        |                                 ~~~~~~~~~~~~
> 
> Fixes: 76a3451b64c6 ("scsi: aacraid: Move the SCSI pointer to private command data")
> Cc: Bart Van Assche <bvanassche@acm.org>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
> Cc: Adaptec OEM Raid Solutions <aacraid@microsemi.com>
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: linux-scsi@vger.kernel.org
> Cc: stable@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>   drivers/scsi/aacraid/aachba.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c
> index 4d4cb47b3846..24c049eff157 100644
> --- a/drivers/scsi/aacraid/aachba.c
> +++ b/drivers/scsi/aacraid/aachba.c
> @@ -818,8 +818,8 @@ static void aac_probe_container_scsi_done(struct scsi_cmnd *scsi_cmnd)
>   
>   int aac_probe_container(struct aac_dev *dev, int cid)
>   {
> -	struct scsi_cmnd *scsicmd = kzalloc(sizeof(*scsicmd), GFP_KERNEL);
> -	struct aac_cmd_priv *cmd_priv = aac_priv(scsicmd);
> +	struct aac_cmd_priv *cmd_priv;
> +	struct scsi_cmnd *scsicmd = kzalloc(sizeof(*scsicmd) + sizeof(*cmd_priv), GFP_KERNEL);
>   	struct scsi_device *scsidev = kzalloc(sizeof(*scsidev), GFP_KERNEL);
>   	int status;
>   
> @@ -838,6 +838,7 @@ int aac_probe_container(struct aac_dev *dev, int cid)
>   		while (scsicmd->device == scsidev)
>   			schedule();
>   	kfree(scsidev);
> +	cmd_priv = aac_priv(scsicmd);
>   	status = cmd_priv->status;
>   	kfree(scsicmd);
>   	return status;
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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