From 08224f38acdf5e391dda43e4e004e4ddc5c00302 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Wed, 9 Sep 2020 23:49:51 +0200
Subject: [PATCH] Use sockaddr_un_set_path() in socket_address_parse()

Two functional changes:
- "/" is now refused. The test is adjusted.
- The trailing NUL is *not* included in the returned size for abstract size. The
  comments in sockaddr_un_set_path() indicate that this is the right thing to do,
  and the code in socket_address_parse() wasn't doing that.
---
 src/shared/socket-netlink.c    | 33 +++++++--------------------------
 src/test/test-socket-netlink.c |  2 +-
 2 files changed, 8 insertions(+), 27 deletions(-)

diff --git a/src/shared/socket-netlink.c b/src/shared/socket-netlink.c
index 76b68dfa1c..23970dbe55 100644
--- a/src/shared/socket-netlink.c
+++ b/src/shared/socket-netlink.c
@@ -62,37 +62,18 @@ int socket_address_parse(SocketAddress *a, const char *s) {
         assert(a);
         assert(s);
 
-        if (*s == '/') {
+        if (IN_SET(*s, '/', '@')) {
                 /* AF_UNIX socket */
+                struct sockaddr_un un;
 
-                size_t l = strlen(s);
-                if (l >= sizeof(a->sockaddr.un.sun_path)) /* Note that we refuse non-NUL-terminated sockets when
-                                                           * parsing (the kernel itself is less strict here in what it
-                                                           * accepts) */
-                        return -EINVAL;
+                r = sockaddr_un_set_path(&un, s);
+                if (r < 0)
+                        return r;
 
                 *a = (SocketAddress) {
-                        .sockaddr.un.sun_family = AF_UNIX,
-                        .size = offsetof(struct sockaddr_un, sun_path) + l + 1,
+                        .sockaddr.un = un,
+                        .size = r,
                 };
-                memcpy(a->sockaddr.un.sun_path, s, l);
-
-        } else if (*s == '@') {
-                /* Abstract AF_UNIX socket */
-
-                size_t l = strlen(s+1);
-                if (l >= sizeof(a->sockaddr.un.sun_path) - 1) /* Note that we refuse non-NUL-terminated sockets here
-                                                               * when parsing, even though abstract namespace sockets
-                                                               * explicitly allow embedded NUL bytes and don't consider
-                                                               * them special. But it's simply annoying to debug such
-                                                               * sockets. */
-                        return -EINVAL;
-
-                *a = (SocketAddress) {
-                        .sockaddr.un.sun_family = AF_UNIX,
-                        .size = offsetof(struct sockaddr_un, sun_path) + 1 + l,
-                };
-                memcpy(a->sockaddr.un.sun_path+1, s+1, l);
 
         } else if (startswith(s, "vsock:")) {
                 /* AF_VSOCK socket in vsock:cid:port notation */
diff --git a/src/test/test-socket-netlink.c b/src/test/test-socket-netlink.c
index ac191851fa..afb7038621 100644
--- a/src/test/test-socket-netlink.c
+++ b/src/test/test-socket-netlink.c
@@ -76,7 +76,7 @@ static void test_socket_address_parse(void) {
         test_socket_address_parse_one("[::1]:1234%xxxxasdf", -ENODEV, 0, NULL);
         test_socket_address_parse_one("192.168.1.254:8888", 0, AF_INET, NULL);
         test_socket_address_parse_one("/foo/bar", 0, AF_UNIX, NULL);
-        test_socket_address_parse_one("/", 0, AF_UNIX, NULL);
+        test_socket_address_parse_one("/", -EINVAL, 0, NULL);
         test_socket_address_parse_one("@abstract", 0, AF_UNIX, NULL);
 
         {