RE: [PATCH] scsi: myrs: Replacing snprintf with scnprintf

[David Laight]

From: wuyonggang001@xxxxxxxxxx
> Sent: 14 June 2023 06:56
> 
> Fix the following coccicheck warning:
> 
> drivers/scsi/myrs.c:1411:8-16: WARNING: use scnprintf or sprintf

That is nothing like the world best commit message.

Also if any of the snprintf() actually overflow the terminating
'\n' is lost - that will have unexpected effects over and above
the truncation.

In fact all the buffer sizes are bogus - did you even look at the code.
I think they should all be using sysfs_emit().

There is also this one:
	char serial[17];

	memcpy(serial, cs->ctlr_info->serial_number, 16);
	serial[16] = '\0';
	return snprintf(buf, 16, "%s\n", serial);
A "%.16s\n" format will have the desired effect.
But completely untested with long names because the 16 isn't big enough.

	David


> 
> Signed-off-by: Yonggang Wu <wuyonggang001@xxxxxxxxxx>
> ---
>   drivers/scsi/myrs.c | 22 +++++++++++-----------
>   1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c
> index a1eec65a9713..ced1d2fbd862 100644
> --- a/drivers/scsi/myrs.c
> +++ b/drivers/scsi/myrs.c
> @@ -939,7 +939,7 @@ static ssize_t raid_state_show(struct device *dev,
>       int ret;
> 
>       if (!sdev->hostdata)
> -        return snprintf(buf, 16, "Unknown\n");
> +        return scnprintf(buf, 16, "Unknown\n");
> 
>       if (sdev->channel >= cs->ctlr_info->physchan_present) {
>           struct myrs_ldev_info *ldev_info = sdev->hostdata;
> @@ -1058,7 +1058,7 @@ static ssize_t raid_level_show(struct device *dev,
>       const char *name = NULL;
> 
>       if (!sdev->hostdata)
> -        return snprintf(buf, 16, "Unknown\n");
> +        return scnprintf(buf, 16, "Unknown\n");
> 
>       if (sdev->channel >= cs->ctlr_info->physchan_present) {
>           struct myrs_ldev_info *ldev_info;
> @@ -1086,7 +1086,7 @@ static ssize_t rebuild_show(struct device *dev,
>       unsigned char status;
> 
>       if (sdev->channel < cs->ctlr_info->physchan_present)
> -        return snprintf(buf, 32, "physical device - not rebuilding\n");
> +        return scnprintf(buf, 32, "physical device - not
> rebuilding\n");
> 
>       ldev_info = sdev->hostdata;
>       ldev_num = ldev_info->ldev_num;
> @@ -1190,7 +1190,7 @@ static ssize_t consistency_check_show(struct
> device *dev,
>       unsigned short ldev_num;
> 
>       if (sdev->channel < cs->ctlr_info->physchan_present)
> -        return snprintf(buf, 32, "physical device - not checking\n");
> +        return scnprintf(buf, 32, "physical device - not checking\n");
> 
>       ldev_info = sdev->hostdata;
>       if (!ldev_info)
> @@ -1303,7 +1303,7 @@ static ssize_t serial_show(struct device *dev,
> 
>       memcpy(serial, cs->ctlr_info->serial_number, 16);
>       serial[16] = '\0';
> -    return snprintf(buf, 16, "%s\n", serial);
> +    return scnprintf(buf, 16, "%s\n", serial);
>   }
>   static DEVICE_ATTR_RO(serial);
> 
> @@ -1313,7 +1313,7 @@ static ssize_t ctlr_num_show(struct device *dev,
>       struct Scsi_Host *shost = class_to_shost(dev);
>       struct myrs_hba *cs = shost_priv(shost);
> 
> -    return snprintf(buf, 20, "%d\n", cs->host->host_no);
> +    return scnprintf(buf, 20, "%d\n", cs->host->host_no);
>   }
>   static DEVICE_ATTR_RO(ctlr_num);
> 
> @@ -1388,7 +1388,7 @@ static ssize_t model_show(struct device *dev,
>       struct Scsi_Host *shost = class_to_shost(dev);
>       struct myrs_hba *cs = shost_priv(shost);
> 
> -    return snprintf(buf, 28, "%s\n", cs->model_name);
> +    return scnprintf(buf, 28, "%s\n", cs->model_name);
>   }
>   static DEVICE_ATTR_RO(model);
> 
> @@ -1398,7 +1398,7 @@ static ssize_t ctlr_type_show(struct device *dev,
>       struct Scsi_Host *shost = class_to_shost(dev);
>       struct myrs_hba *cs = shost_priv(shost);
> 
> -    return snprintf(buf, 4, "%d\n", cs->ctlr_info->ctlr_type);
> +    return scnprintf(buf, 4, "%d\n", cs->ctlr_info->ctlr_type);
>   }
>   static DEVICE_ATTR_RO(ctlr_type);
> 
> @@ -1408,7 +1408,7 @@ static ssize_t cache_size_show(struct device *dev,
>       struct Scsi_Host *shost = class_to_shost(dev);
>       struct myrs_hba *cs = shost_priv(shost);
> 
> -    return snprintf(buf, 8, "%d MB\n", cs->ctlr_info->cache_size_mb);
> +    return scnprintf(buf, 8, "%d MB\n", cs->ctlr_info->cache_size_mb);
>   }
>   static DEVICE_ATTR_RO(cache_size);
> 
> @@ -1418,7 +1418,7 @@ static ssize_t firmware_show(struct device *dev,
>       struct Scsi_Host *shost = class_to_shost(dev);
>       struct myrs_hba *cs = shost_priv(shost);
> 
> -    return snprintf(buf, 16, "%d.%02d-%02d\n",
> +    return scnprintf(buf, 16, "%d.%02d-%02d\n",
>               cs->ctlr_info->fw_major_version,
>               cs->ctlr_info->fw_minor_version,
>               cs->ctlr_info->fw_turn_number);
> @@ -1488,7 +1488,7 @@ static ssize_t
> disable_enclosure_messages_show(struct device *dev,
>       struct Scsi_Host *shost = class_to_shost(dev);
>       struct myrs_hba *cs = shost_priv(shost);
> 
> -    return snprintf(buf, 3, "%d\n", cs->disable_enc_msg);
> +    return scnprintf(buf, 3, "%d\n", cs->disable_enc_msg);
>   }
> 
>   static ssize_t disable_enclosure_messages_store(struct device *dev,

-
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