From f545ad4928fa1f27a3075265182b38a4f939a5f7 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Mon, 17 Jan 2022 10:21:34 +0100
Subject: [PATCH] CVE-2022-23218: Buffer overflow in sunrpc svcunix_create (bug
 28768)

The sunrpc function svcunix_create suffers from a stack-based buffer
overflow with overlong pathname arguments.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---
 sunrpc/svc_unix.c     | 11 ++++-------
 1 files changed, 4 insertions(+), 7 deletions(-)
 create mode 100644 sunrpc/svc_unix.c
 
diff --git a/sunrpc/svc_unix.c b/sunrpc/svc_unix.c
index f2280b4..67177a2 100644
--- a/sunrpc/svc_unix.c
+++ b/sunrpc/svc_unix.c
@@ -154,7 +154,10 @@ svcunix_create (int sock, u_int sendsize, u_int recvsize, char *path)
   SVCXPRT *xprt;
   struct unix_rendezvous *r;
   struct sockaddr_un addr;
-  socklen_t len = sizeof (struct sockaddr_in);
+  socklen_t len = sizeof (addr);
+
+  if (__sockaddr_un_set (&addr, path) < 0)
+    return NULL;
 
   if (sock == RPC_ANYSOCK)
     {
@@ -165,12 +168,6 @@ svcunix_create (int sock, u_int sendsize, u_int recvsize, char *path)
 	}
       madesock = TRUE;
     }
-  memset (&addr, '\0', sizeof (addr));
-  addr.sun_family = AF_UNIX;
-  len = strlen (path) + 1;
-  memcpy (addr.sun_path, path, len);
-  len += sizeof (addr.sun_family);
-
   __bind (sock, (struct sockaddr *) &addr, len);
 
   if (__getsockname (sock, (struct sockaddr *) &addr, &len) != 0
