[PATCH v4 16/19] efi/http: Enclose literal IPv6 addresses in square brackets

[Robbie Harwood]

From: Javier Martinez Canillas <javierm@redhat.com>

According to RFC 2732 (https://www.ietf.org/rfc/rfc2732.txt), literal IPv6
addresses must be enclosed in square brackets. But GRUB currently does not
do this and is causing HTTP servers to send Bad Request (400) responses.

For example, the following is the HTTP stream when fetching a config file:

HEAD /EFI/BOOT/grub.cfg HTTP/1.1
Host: 2000:dead:beef:a::1
Accept: */*
User-Agent: UefiHttpBoot/1.0

HTTP/1.1 400 Bad Request
Date: Thu, 05 Mar 2020 14:46:02 GMT
Server: Apache/2.4.41 (Fedora) OpenSSL/1.1.1d
Connection: close
Content-Type: text/html; charset=iso-8859-1

and after enclosing the IPv6 address the HTTP request is successful:

HEAD /EFI/BOOT/grub.cfg HTTP/1.1
Host: [2000:dead:beef:a::1]
Accept: */*
User-Agent: UefiHttpBoot/1.0

HTTP/1.1 200 OK
Date: Thu, 05 Mar 2020 14:48:04 GMT
Server: Apache/2.4.41 (Fedora) OpenSSL/1.1.1d
Last-Modified: Thu, 27 Feb 2020 17:45:58 GMT
ETag: "206-59f924b24b1da"
Accept-Ranges: bytes
Content-Length: 518

Resolves: rhbz#1732765

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
 grub-core/net/efi/http.c | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/grub-core/net/efi/http.c b/grub-core/net/efi/http.c
index ed0d40bee3..e485c27ee1 100644
--- a/grub-core/net/efi/http.c
+++ b/grub-core/net/efi/http.c
@@ -147,13 +147,7 @@ efihttp_request (grub_efi_http_t *http, char *server, char 
*name, int use_https,
   grub_efi_status_t status;
   grub_efi_boot_services_t *b = grub_efi_system_table->boot_services;
   char *url = NULL;
-
-  request_headers[0].field_name = (grub_efi_char8_t *) "Host";
-  request_headers[0].field_value = (grub_efi_char8_t *) server;
-  request_headers[1].field_name = (grub_efi_char8_t *) "Accept";
-  request_headers[1].field_value = (grub_efi_char8_t *) "*/*";
-  request_headers[2].field_name = (grub_efi_char8_t *) "User-Agent";
-  request_headers[2].field_value = (grub_efi_char8_t *) "UefiHttpBoot/1.0";
+  char *hostname = NULL;
 
   {
     grub_efi_ipv6_address_t address;
@@ -163,9 +157,24 @@ efihttp_request (grub_efi_http_t *http, char *server, char 
*name, int use_https,
     const char *protocol = (use_https == 1) ? "https" : "http";
 
     if (grub_efi_string_to_ip6_address (server, &address, &rest) && *rest == 0)
-      url = grub_xasprintf ("%s://[%s]%s", protocol, server, name);
+      {
+        hostname = grub_xasprintf ("[%s]", server);
+        if (!hostname)
+          return GRUB_ERR_OUT_OF_MEMORY;
+
+        server = hostname;
+
+        url = grub_xasprintf ("%s://%s%s", protocol, server, name);
+        if (!url)
+          {
+            grub_free (hostname);
+            return GRUB_ERR_OUT_OF_MEMORY;
+          }
+      }
     else
-      url = grub_xasprintf ("%s://%s%s", protocol, server, name);
+      {
+        url = grub_xasprintf ("%s://%s%s", protocol, server, name);
+      }
 
     if (!url)
       {
@@ -190,6 +199,13 @@ efihttp_request (grub_efi_http_t *http, char *server, char 
*name, int use_https,
     request_data.url = ucs2_url;
   }
 
+  request_headers[0].field_name = (grub_efi_char8_t *) "Host";
+  request_headers[0].field_value = (grub_efi_char8_t *) server;
+  request_headers[1].field_name = (grub_efi_char8_t *) "Accept";
+  request_headers[1].field_value = (grub_efi_char8_t *) "*/*";
+  request_headers[2].field_name = (grub_efi_char8_t *) "User-Agent";
+  request_headers[2].field_value = (grub_efi_char8_t *) "UefiHttpBoot/1.0";
+
   request_data.method = (headeronly > 0) ? GRUB_EFI_HTTPMETHODHEAD : 
GRUB_EFI_HTTPMETHODGET;
 
   request_message.data.request = &request_data;
@@ -219,6 +235,9 @@ efihttp_request (grub_efi_http_t *http, char *server, char 
*name, int use_https,
 
   status = efi_call_2 (http->request, http, &request_token);
 
+  if (hostname)
+    grub_free (hostname);
+
   if (status != GRUB_EFI_SUCCESS)
     {
       efi_call_1 (b->close_event, request_token.event);
-- 
2.39.0