[Devel] [PATCH rh7] ve/net/core: allow to call setsockopt(SO_RCVBUFFORCE) from Containers

[Konstantin Khorenko]

On 11/05/2020 06:20 PM, Konstantin Khorenko wrote:
> "nft" util (in CentOS 8 environment) does use setsockopt(SO_RCVBUFFORCE)
> unconditionally, so we have to allow it from inside a Container.
>
> At the same time we don't want to allow a Container to set too much
> memory for a socket, so just threat SO_RCVBUFFORCE like SO_RCVBUF if
> called inside a Container.
>
> Simple rule to test:
>
>   # NFT=/usr/sbin/nft ./run-tests.sh -v -g testcases/nft-f/0011manydefines_0
>
> which fails inside a Container because of not enough rcb buffer because
> of failed
>   setsockopt(3, SOL_SOCKET, SO_RCVBUFFORCE, [10561584], 4) = -1
>   EPERM (Operation not permitted)

https://jira.sw.ru/browse/PSBM-121791

> Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
> ---
>  net/core/sock.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 07ea42f976cf..44e91c8c0f0a 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -793,6 +793,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
>  		goto set_sndbuf;
>
>  	case SO_RCVBUF:
> +unpriv_rcvbuf:
>  		/* Don't error on this BSD doesn't and if you think
>  		 * about it this is right. Otherwise apps have to
>  		 * play 'guess the biggest size' games. RCVBUF/SNDBUF
> @@ -824,11 +825,15 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
>  		break;
>
>  	case SO_RCVBUFFORCE:
> -		if (!capable(CAP_NET_ADMIN)) {
> +		if (!ve_capable(CAP_NET_ADMIN)) {
>  			ret = -EPERM;
>  			break;
>  		}
>
> +		/* nft utility uses this sockopt in CentOS 8 env */
> +		if (!ve_is_super(get_exec_env()))
> +			goto unpriv_rcvbuf;
> +
>  		/* No negative values (to prevent underflow, as val will be
>  		 * multiplied by 2).
>  		 */
>