Author: Felipe Gasper <[email protected]>
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 <[email protected]>
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));
+}
+
static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
u32 portid, u32 seq, u32 flags, int sk_ino)
{
@@ -156,6 +161,10 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_r
if (nla_put_u8(skb, UNIX_DIAG_SHUTDOWN, sk->sk_shutdown))
goto out_nlmsg_trim;
+ if ((req->udiag_show & UDIAG_SHOW_UID) &&
+ sk_diag_dump_uid(sk, skb))
+ goto out_nlmsg_trim;
+
nlmsg_end(skb, nlh);
return 0;
> On May 16, 2019, at 8:25 PM, Felipe <[email protected]> wrote:
>
> Author: Felipe Gasper <[email protected]>
> 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 <[email protected]>
>
> 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.
> On May 17, 2019, at 12:59 AM, Andy Lutomirski <[email protected]> wrote:
>
>> On May 16, 2019, at 8:25 PM, Felipe <[email protected]> wrote:
>>
>> Author: Felipe Gasper <[email protected]>
>> 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 <[email protected]>
>>
>> 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.
Thank you for pointing this out.
Would it suffice to get the userns as: “sk_user_ns(sk)”?
Or would it be better to pass struct netlink_callback *cb from unix_diag_dump() to sk_diag_dump() to sk_diag_fill(), then to the new function to add the UID?
cheers,
-Felipe Gasper