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From: Bart Van Assche <bvanassche@acm.org>
To: zhengbin <zhengbin13@huawei.com>,
	jejb@linux.ibm.com, martin.petersen@oracle.com,
	linux-scsi@vger.kernel.org
Cc: yi.zhang@huawei.com
Subject: Re: [PATCH v3] scsi: core: fix uninit-value access of variable sshdr
Date: Wed, 16 Oct 2019 19:45:50 -0700
Message-ID: <3e3f05fb-387a-d55f-fc90-72d01c6d026a@acm.org> (raw)
In-Reply-To: <1570850706-12063-1-git-send-email-zhengbin13@huawei.com>

On 2019-10-11 20:25, zhengbin wrote:
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 5447738..d5e29c5 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -255,6 +255,13 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
>  	struct scsi_request *rq;
>  	int ret = DRIVER_ERROR << 24;
> 
> +	/*
> +	 * Zero-initialize sshdr for those callers that check the *sshdr
> +	 * contents even if no sense data is available.
> +	 */
> +	if (sshdr)
> +		memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
> +
>  	req = blk_get_request(sdev->request_queue,
>  			data_direction == DMA_TO_DEVICE ?
>  			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);

Although I don't have a strong opinion about this, I'm still wondering
whether 'sshdr' should be initialized in __scsi_execute() or by its caller.

> diff --git a/drivers/scsi/sr_ioctl.c b/drivers/scsi/sr_ioctl.c
> index ffcf902..335cfdd 100644
> --- a/drivers/scsi/sr_ioctl.c
> +++ b/drivers/scsi/sr_ioctl.c
> @@ -206,6 +206,11 @@ int sr_do_ioctl(Scsi_CD *cd, struct packet_command *cgc)
> 
>  	/* Minimal error checking.  Ignore cases we know about, and report the rest. */
>  	if (driver_byte(result) != 0) {
> +		if (!scsi_sense_valid(sshdr)) {
> +			err = -EIO;
> +			goto out;
> +		}
> +
>  		switch (sshdr->sense_key) {
>  		case UNIT_ATTENTION:
>  			SDev->changed = 1;

Shouldn't this be a separate patch?

Thanks,

Bart.

  parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-12  3:25 zhengbin
2019-10-17  0:05 ` Finn Thain
2019-10-17  1:16   ` zhengbin (A)
2019-10-17  2:45 ` Bart Van Assche [this message]
2019-10-17  3:26   ` zhengbin (A)

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