[lxc-devel] [PATCH] Fix clearing IPv4/IPv6 addresses

[Serge Hallyn]

Quoting Stéphane Graber (stgraber at ubuntu.com):
> Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>

Looks good, except that in both functions in the case where
the value is being cleared you may leak the previously allocated
gw.

> ---
>  src/lxc/confile.c | 35 ++++++++++++++---------------------
>  1 file changed, 14 insertions(+), 21 deletions(-)
> 
> diff --git a/src/lxc/confile.c b/src/lxc/confile.c
> index be81f5d..e9cc474 100644
> --- a/src/lxc/confile.c
> +++ b/src/lxc/confile.c
> @@ -787,29 +787,25 @@ static int config_network_ipv4_gateway(const char *key, const char *value,
>  			               struct lxc_conf *lxc_conf)
>  {
>  	struct lxc_netdev *netdev;
> -	struct in_addr *gw;
>  
>  	netdev = network_netdev(key, value, &lxc_conf->network);
>  	if (!netdev)
>  		return -1;
>  
> -	gw = malloc(sizeof(*gw));
> -	if (!gw) {
> -		SYSERROR("failed to allocate ipv4 gateway address");
> -		return -1;
> -	}
> -
> -	if (!value) {
> -		ERROR("no ipv4 gateway address specified");
> -		free(gw);
> -		return -1;
> -	}
> -
> -	if (!strcmp(value, "auto")) {
> -		free(gw);
> +	if (!value || strlen(value) == 0) {
> +		netdev->ipv4_gateway = NULL;
> +	} else if (!strcmp(value, "auto")) {
>  		netdev->ipv4_gateway = NULL;
>  		netdev->ipv4_gateway_auto = true;
>  	} else {
> +		struct in_addr *gw;
> +
> +		gw = malloc(sizeof(*gw));
> +		if (!gw) {
> +			SYSERROR("failed to allocate ipv4 gateway address");
> +			return -1;
> +		}
> +
>  		if (!inet_pton(AF_INET, value, gw)) {
>  			SYSERROR("invalid ipv4 gateway address: %s", value);
>  			free(gw);
> @@ -892,12 +888,9 @@ static int config_network_ipv6_gateway(const char *key, const char *value,
>  	if (!netdev)
>  		return -1;
>  
> -	if (!value) {
> -		ERROR("no ipv6 gateway address specified");
> -		return -1;
> -	}
> -
> -	if (!strcmp(value, "auto")) {
> +	if (!value || strlen(value) == 0) {
> +		netdev->ipv4_gateway = NULL;
> +	} else if (!strcmp(value, "auto")) {
>  		netdev->ipv6_gateway = NULL;
>  		netdev->ipv6_gateway_auto = true;
>  	} else {
> -- 
> 1.9.1
> 
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