[glib: 10/19] gsocks5proxy: Fix buffer overflow on a really long domain name

[Philip Withnall <pwithnall src gnome org>]

commit b32727d43d9d11aa017f1f29648ad5019376537c
Author: Egor Bychin <e bychin drweb com>
Date:   Mon Oct 11 14:07:01 2021 +0300

    gsocks5proxy: Fix buffer overflow on a really long domain name

 gio/gsocks5proxy.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)
---
diff --git a/gio/gsocks5proxy.c b/gio/gsocks5proxy.c
index 873db7ea6..948ac8b8b 100644
--- a/gio/gsocks5proxy.c
+++ b/gio/gsocks5proxy.c
@@ -328,7 +328,7 @@ set_connect_msg (guint8       *msg,
  *
  * The parser only requires 4 bytes.
  */
-#define SOCKS5_CONN_REP_LEN      255
+#define SOCKS5_CONN_REP_LEN      257
 static gboolean
 parse_connect_reply (const guint8 *data, gint *atype, GError **error)
 {
@@ -509,7 +509,7 @@ g_socks5_proxy_connect (GProxy            *proxy,
       guint8 data[SOCKS5_CONN_REP_LEN];
       gint atype;
 
-      if (!g_input_stream_read_all (in, data, 4, NULL,
+      if (!g_input_stream_read_all (in, data, 4 /* VER, REP, RSV, ATYP */, NULL,
                                    cancellable, error))
        goto error;
 
@@ -519,23 +519,26 @@ g_socks5_proxy_connect (GProxy            *proxy,
       switch (atype)
        {
          case SOCKS5_ATYP_IPV4:
-           if (!g_input_stream_read_all (in, data, 6, NULL,
-                                         cancellable, error))
+           if (!g_input_stream_read_all (in, data,
+                                         4 /* IPv4 length */ + 2 /* port */,
+                                         NULL, cancellable, error))
              goto error;
            break;
 
          case SOCKS5_ATYP_IPV6:
-           if (!g_input_stream_read_all (in, data, 18, NULL,
-                                         cancellable, error))
+           if (!g_input_stream_read_all (in, data,
+                                         16 /* IPv6 length */ + 2 /* port */,
+                                         NULL, cancellable, error))
              goto error;
            break;
 
          case SOCKS5_ATYP_DOMAINNAME:
-           if (!g_input_stream_read_all (in, data, 1, NULL,
-                                         cancellable, error))
+           if (!g_input_stream_read_all (in, data, 1 /* domain name length */,
+                                         NULL, cancellable, error))
              goto error;
-           if (!g_input_stream_read_all (in, data, data[0] + 2, NULL,
-                                         cancellable, error))
+           if (!g_input_stream_read_all (in, data,
+                                         data[0] /* domain name length */ + 2 /* port */,
+                                         NULL, cancellable, error))
              goto error;
            break;
        }