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SubjectRe: [RFC PATCH v4 2/3] vfio: platform: access device property as a list of strings
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On Wed, 2015-09-09 at 11:17 +0200, Baptiste Reynal wrote:
> From: Antonios Motakis <a.motakis@virtualopensystems.com>
>
> Certain device properties (e.g. the device node name, the compatible
> string), are available as a list of strings (separated by the null
> terminating character). Let the VFIO user query this type of properties.
>
> Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
> Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
>
> ---
> v3 -> v4:
> - The list length is computed before strings copy. If the entire list
> doesn't fit, no strings are copied to the user.
> ---
> drivers/vfio/platform/properties.c | 43 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/platform/properties.c b/drivers/vfio/platform/properties.c
> index 98754c2..8bf9c8f 100644
> --- a/drivers/vfio/platform/properties.c
> +++ b/drivers/vfio/platform/properties.c
> @@ -22,7 +22,48 @@ static int dev_property_get_strings(struct device *dev, uint32_t *flags,
> char *name, unsigned *lenp,
> void __user *datap, unsigned long datasz)
> {
> - return -EINVAL;
> + const char **val;
> + int n, i, ret;
> +
> + if (lenp == NULL)
> + return -EFAULT;

Paranoia?

> +
> + *lenp = 0;
> +
> + n = device_property_read_string_array(dev, name, NULL, 0);
> + if (n < 0)
> + return n;
> +
> + val = kcalloc(n, sizeof(char *), GFP_KERNEL);
> + if (!val)
> + return -ENOMEM;
> +
> + ret = device_property_read_string_array(dev, name, val, n);
> + if (ret < 0)
> + goto out;
> +
> + for (i = 0; i < n; i++)
> + *lenp += strlen(val[i]) + 1;
> +
> + if (datasz < *lenp) {
> + ret = -E2BIG;
> + goto out;
> + }
> +
> + for (i = 0; i < n; i++) {
> + size_t len = strlen(val[i]) + 1;
> +
> + if (copy_to_user(datap, val[i], strlen(val[i]) + 1)) {

No need to call strlen() again here

> + ret = -EFAULT;
> + goto out;
> + }
> +
> + datap += len;
> + }
> +
> +out:
> + kfree(val);
> + return ret;
> }
>
> static int dev_property_get_uint(struct device *dev, uint32_t *flags,





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