Re: [PATCH] scsi: prevent stack buffer overflow in host_reset

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Thu, 2012-11-15 at 15:51 -0500, Sasha Levin wrote:
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index ce5224c..77ba946 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -249,9 +249,9 @@ static DEVICE_ATTR(active_mode, S_IRUGO | S_IWUSR, show_shost_active_mode, NULL)
>  
>  static int check_reset_type(char *str)
>  {
> -	if (strncmp(str, "adapter", 10) == 0)
> +	if (sysfs_streq(str, "adapter"))
>  		return SCSI_ADAPTER_RESET;
> -	else if (strncmp(str, "firmware", 10) == 0)
> +	else if (sysfs_streq(str, "firmware"))
>  		return SCSI_FIRMWARE_RESET;
>  	else
>  		return 0;
> @@ -264,12 +264,9 @@ store_host_reset(struct device *dev, struct device_attribute *attr,
>  	struct Scsi_Host *shost = class_to_shost(dev);
>  	struct scsi_host_template *sht = shost->hostt;
>  	int ret = -EINVAL;
> -	char str[10];
>  	int type;
>  
> -	sscanf(buf, "%s", str);
> -	type = check_reset_type(str);
> -
> +	type = check_reset_type(buf);
>  	if (!type)
>  		goto exit_store_host_reset;

You didn't compile test this:

  CC [M]  drivers/scsi/scsi_sysfs.o
drivers/scsi/scsi_sysfs.c: In function ‘store_host_reset’:
drivers/scsi/scsi_sysfs.c:269:2: warning: passing argument 1 of ‘check_reset_type’ discards ‘const’ qualifier from pointer target type [enabled by default]
drivers/scsi/scsi_sysfs.c:250:12: note: expected ‘char *’ but argument is of type ‘const char *’

It needs a const in check_reset_type().

I've added it.

James