[dpdk-dev] [PATCH v2] common/mlx5: fix netlink buffer allocation from stack

[Raslan Darawsheh]

Hi,

> -----Original Message-----
> From: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
> Sent: Thursday, May 14, 2020 10:11 AM
> To: dev at dpdk.org
> Cc: Matan Azrad <matan at mellanox.com>; Raslan Darawsheh
> <rasland at mellanox.com>; stephen at networkplumber.org; Nélio Laranjeiro
> <nelio.laranjeiro at 6wind.com>; stable at dpdk.org
> Subject: [PATCH v2] common/mlx5: fix netlink buffer allocation from stack
> 
> The buffer size to receive netlink reply messages is relatively
> large (32K), and it is allocated on the stack and it might
> break in application is using smaller per-thread stacks.
> This patch allocates temporary buffer from heap.
> 
> Fixes: ccdcba53a3f4 ("net/mlx5: use Netlink to add/remove MAC addresses")
> Cc: nelio.laranjeiro at 6wind.com
> Cc: stable at dpdk.org
> 
> Reported-by: Stephen Hemminger <stephen at networkplumber.org>
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
> 
> ---
> v2: allocation from heap, instead of reducing buffer size
> v1:
> https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpatch
> es.dpdk.org%2Fpatch%2F69158%2F&data=02%7C01%7Crasland%40mell
> anox.com%7C1e38e272cede42d2cfc008d7f7d60e00%7Ca652971c7d2e4d9ba6
> a4d149256f461b%7C0%7C0%7C637250371034928200&sdata=cZ1hFsnSZz
> 5oMj8zOLbB6vmcthY1FnPZWa%2FgoNDibmg%3D&reserved=0
> ---
>  drivers/common/mlx5/mlx5_nl.c | 27 +++++++++++++++++++--------
>  1 file changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/common/mlx5/mlx5_nl.c
> b/drivers/common/mlx5/mlx5_nl.c
> index 65efcd3..1a1033a 100644
> --- a/drivers/common/mlx5/mlx5_nl.c
> +++ b/drivers/common/mlx5/mlx5_nl.c
> @@ -330,10 +330,10 @@ struct mlx5_nl_ifindex_data {
>  	     void *arg)
>  {
>  	struct sockaddr_nl sa;
> -	char buf[MLX5_RECV_BUF_SIZE];
> +	void *buf = malloc(MLX5_RECV_BUF_SIZE);
>  	struct iovec iov = {
>  		.iov_base = buf,
> -		.iov_len = sizeof(buf),
> +		.iov_len = MLX5_RECV_BUF_SIZE,
>  	};
>  	struct msghdr msg = {
>  		.msg_name = &sa,
> @@ -345,6 +345,10 @@ struct mlx5_nl_ifindex_data {
>  	int multipart = 0;
>  	int ret = 0;
> 
> +	if (!buf) {
> +		rte_errno = ENOMEM;
> +		return -rte_errno;
> +	}
>  	do {
>  		struct nlmsghdr *nh;
>  		int recv_bytes = 0;
> @@ -353,7 +357,8 @@ struct mlx5_nl_ifindex_data {
>  			recv_bytes = recvmsg(nlsk_fd, &msg, 0);
>  			if (recv_bytes == -1) {
>  				rte_errno = errno;
> -				return -rte_errno;
> +				ret = -rte_errno;
> +				goto exit;
>  			}
>  			nh = (struct nlmsghdr *)buf;
>  		} while (nh->nlmsg_seq != sn);
> @@ -365,24 +370,30 @@ struct mlx5_nl_ifindex_data {
> 
>  				if (err_data->error < 0) {
>  					rte_errno = -err_data->error;
> -					return -rte_errno;
> +					ret = -rte_errno;
> +					goto exit;
>  				}
>  				/* Ack message. */
> -				return 0;
> +				ret = 0;
> +				goto exit;
>  			}
>  			/* Multi-part msgs and their trailing DONE message.
> */
>  			if (nh->nlmsg_flags & NLM_F_MULTI) {
> -				if (nh->nlmsg_type == NLMSG_DONE)
> -					return 0;
> +				if (nh->nlmsg_type == NLMSG_DONE) {
> +					ret =  0;
> +					goto exit;
> +				}
>  				multipart = 1;
>  			}
>  			if (cb) {
>  				ret = cb(nh, arg);
>  				if (ret < 0)
> -					return ret;
> +					goto exit;
>  			}
>  		}
>  	} while (multipart);
> +exit:
> +	free(buf);
>  	return ret;
>  }
> 
> --
> 1.8.3.1


Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh