> On May 16, 2019, at 8:25 PM, Felipe <felipe@xxxxxxxxxxxxxxxx> wrote:
>
> Author: Felipe Gasper <felipe@xxxxxxxxxxxxxxxx>
> Date: Thu May 16 12:16:53 2019 -0500
>
> Add UNIX_DIAG_UID to Netlink UNIX socket diagnostics.
>
> This adds the ability for Netlink to report a socket’s UID along with the
> other UNIX socket diagnostic information that is already available. This will
> allow diagnostic tools greater insight into which users control which socket.
>
> Signed-off-by: Felipe Gasper <felipe@xxxxxxxxxxxxxxxx>
>
> diff --git a/include/uapi/linux/unix_diag.h b/include/uapi/linux/unix_diag.h
> index 5c502fd..a198857 100644
> --- a/include/uapi/linux/unix_diag.h
> +++ b/include/uapi/linux/unix_diag.h
> @@ -20,6 +20,7 @@ struct unix_diag_req {
> #define UDIAG_SHOW_ICONS 0x00000008 /* show pending connections */
> #define UDIAG_SHOW_RQLEN 0x00000010 /* show skb receive queue len */
> #define UDIAG_SHOW_MEMINFO 0x00000020 /* show memory info of a socket */
> +#define UDIAG_SHOW_UID 0x00000040 /* show socket's UID */
>
> struct unix_diag_msg {
> __u8 udiag_family;
> @@ -40,6 +41,7 @@ enum {
> UNIX_DIAG_RQLEN,
> UNIX_DIAG_MEMINFO,
> UNIX_DIAG_SHUTDOWN,
> + UNIX_DIAG_UID,
>
> __UNIX_DIAG_MAX,
> };
> diff --git a/net/unix/diag.c b/net/unix/diag.c
> index 3183d9b..011f56c 100644
> --- a/net/unix/diag.c
> +++ b/net/unix/diag.c
> @@ -110,6 +110,11 @@ static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
> return nla_put(nlskb, UNIX_DIAG_RQLEN, sizeof(rql), &rql);
> }
>
> +static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb)
> +{
> + return nla_put(nlskb, UNIX_DIAG_UID, sizeof(kuid_t), &(sk->sk_uid));
That type is called *k* uid_t because it’s internal to the kernel. You
probably want from_kuid_munged(), which will fix it up for an
appropriate userns. Presumably you want sk’s netns’s userns.
