[dpdk-dev] [PATCH 3/6] net/tap: check interface name in kvargs

[Wiles, Keith]

> On Jan 11, 2019, at 12:06 PM, Stephen Hemminger <stephen at networkplumber.org> wrote:
> 
> If interface name is passed to remote or iface then check
> the length and for invalid characters. This avoids problems where
> name gets truncated or rejected by kernel.
> 
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> ---
> drivers/net/tap/rte_eth_tap.c | 37 +++++++++++++++++++++++++++++++----
> 1 file changed, 33 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
> index d7f77d664502..6a388eed0dd4 100644
> --- a/drivers/net/tap/rte_eth_tap.c
> +++ b/drivers/net/tap/rte_eth_tap.c
> @@ -37,6 +37,7 @@
> #include <linux/if_tun.h>
> #include <linux/if_ether.h>
> #include <fcntl.h>
> +#include <ctype.h>
> 
> #include <tap_rss.h>
> #include <rte_eth_tap.h>
> @@ -1884,6 +1885,23 @@ eth_dev_tap_create(struct rte_vdev_device *vdev, char *tap_name,
> 	return -EINVAL;
> }
> 
> +/* make sure name is a possible Linux network device name */
> +static bool is_valid_iface(const char *name)

I am sorry, but the function name must be on the next line as per the style. I know you do not like it, but that is what the style states.
> +{
> +	if (*name == '\0')
> +		return false;
> +
> +	if (strnlen(name, IFNAMSIZ) == IFNAMSIZ)
> +		return false;
> +
> +	while (*name) {
> +		if (*name == '/' || *name == ':' || isspace(*name))
> +			return false;
> +		name++;
> +	}
> +	return true;
> +}
> +
> static int
> set_interface_name(const char *key __rte_unused,
> 		   const char *value,
> @@ -1891,12 +1909,17 @@ set_interface_name(const char *key __rte_unused,
> {
> 	char *name = (char *)extra_args;
> 
> -	if (value)
> +	if (value) {
> +		if (!is_valid_iface(value)) {
> +			TAP_LOG(ERR, "TAP invalid remote interface name (%s)",
> +				value);
> +			return -1;
> +		}
> 		strlcpy(name, value, RTE_ETH_NAME_MAX_LEN);
> -	else
> +	} else {
> 		snprintf(name, RTE_ETH_NAME_MAX_LEN, "%s%d",
> 			 DEFAULT_TAP_NAME, tun_unit - 1);
> -
> +	}

This is also a one line else and the style states to remove the {}.
> 	return 0;
> }
> 
> @@ -1907,8 +1930,14 @@ set_remote_iface(const char *key __rte_unused,
> {
> 	char *name = (char *)extra_args;
> 
> -	if (value)
> +	if (value) {
> +		if (!is_valid_iface(value)) {
> +			TAP_LOG(ERR, "TAP invalid remote interface name (%s)",
> +				value);
> +			return -1;
> +		}
> 		strlcpy(name, value, RTE_ETH_NAME_MAX_LEN);
> +	}
> 
> 	return 0;
> }
> -- 
> 2.20.1
> 

I hate having to be the style police, but until we use something to validate the DPDK coding style (as I posted the uncrustify config last month) we have to keep the style the same or change the DPDK coding standard.

Regards,
Keith