2 files changed, 14 insertions, 0 deletions

diff --git a/include/uapi/linux/unix_diag.h b/include/uapi/linux/unix_diag.h
index 5c502fdf7a42..a1988576fa8a 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 c51a707260fa..9ff64f9df1f3 100644
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -5,9 +5,11 @@
 #include <linux/unix_diag.h>
 #include <linux/skbuff.h>
 #include <linux/module.h>
+#include <linux/uidgid.h>
 #include <net/netlink.h>
 #include <net/af_unix.h>
 #include <net/tcp_states.h>
+#include <net/sock.h>
 
 static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
 {
@@ -111,6 +113,12 @@ 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)
+{
+        uid_t uid = from_kuid_munged(sk_user_ns(nlskb->sk), sock_i_uid(sk));
+        return nla_put(nlskb, UNIX_DIAG_UID, sizeof(uid_t), &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)
 {
@@ -157,6 +165,10 @@ 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;