diff options
Diffstat (limited to 'system/xen/patches/xsa119-unstable.patch')
| -rw-r--r-- | system/xen/patches/xsa119-unstable.patch | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/system/xen/patches/xsa119-unstable.patch b/system/xen/patches/xsa119-unstable.patch new file mode 100644 index 000000000000..f696eb5b6eb6 --- /dev/null +++ b/system/xen/patches/xsa119-unstable.patch @@ -0,0 +1,99 @@ +From f433bfafbaf7d8a41c4c27aa3e8e78b1ab900b69 Mon Sep 17 00:00:00 2001 +From: Ian Campbell <ian.campbell@citrix.com> +Date: Fri, 20 Feb 2015 14:41:09 +0000 +Subject: [PATCH] tools: libxl: Explicitly disable graphics backends on qemu + cmdline + +By default qemu will try to create some sort of backend for the +emulated VGA device, either SDL or VNC. + +However when the user specifies sdl=0 and vnc=0 in their configuration +libxl was not explicitly disabling either backend, which could lead to +one unexpectedly running. + +If either sdl=1 or vnc=1 is configured then both before and after this +change only the backends which are explicitly enabled are configured, +i.e. this issue only occurs when all backends are supposed to have +been disabled. + +This affects qemu-xen and qemu-xen-traditional differently. + +If qemu-xen was compiled with SDL support then this would result in an +SDL window being opened if $DISPLAY is valid, or a failure to start +the guest if not. Passing "-display none" to qemu before any further +-sdl options disables this default behaviour and ensures that SDL is +only started if the libxl configuration demands it. + +If qemu-xen was compiled without SDL support then qemu would instead +start a VNC server listening on ::1 (IPv6 localhost) or 127.0.0.1 +(IPv4 localhost) with IPv6 preferred if available. Explicitly pass +"-vnc none" when vnc is not enabled in the libxl configuration to +remove this possibility. + +qemu-xen-traditional would never start a vnc backend unless asked. +However by default it will start an SDL backend, the way to disable +this is to pass a -vnc option. In other words passing "-vnc none" will +disable both vnc and sdl by default. sdl can then be reenabled if +configured by subsequent use of the -sdl option. + +Tested with both qemu-xen and qemu-xen-traditional built with SDL +support and: + xl cr # defaults + xl cr sdl=0 vnc=0 + xl cr sdl=1 vnc=0 + xl cr sdl=0 vnc=1 + xl cr sdl=0 vnc=0 vga=\"none\" + xl cr sdl=0 vnc=0 nographic=1 +with both valid and invalid $DISPLAY. + +This is XSA-119. + +Reported-by: Sander Eikelenboom <linux@eikelenboom.it> +Signed-off-by: Ian Campbell <ian.campbell@citrix.com> +Acked-by: Ian Jackson <ian.jackson@eu.citrix.com> +--- + tools/libxl/libxl_dm.c | 21 +++++++++++++++++++-- + 1 file changed, 19 insertions(+), 2 deletions(-) + +diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c +index 8599a6a..3b918c6 100644 +--- a/tools/libxl/libxl_dm.c ++++ b/tools/libxl/libxl_dm.c +@@ -180,7 +180,14 @@ static char ** libxl__build_device_model_args_old(libxl__gc *gc, + if (libxl_defbool_val(vnc->findunused)) { + flexarray_append(dm_args, "-vncunused"); + } +- } ++ } else ++ /* ++ * VNC is not enabled by default by qemu-xen-traditional, ++ * however passing -vnc none causes SDL to not be ++ * (unexpectedly) enabled by default. This is overridden by ++ * explicitly passing -sdl below as required. ++ */ ++ flexarray_append_pair(dm_args, "-vnc", "none"); + + if (sdl) { + flexarray_append(dm_args, "-sdl"); +@@ -522,7 +529,17 @@ static char ** libxl__build_device_model_args_new(libxl__gc *gc, + } + + flexarray_append(dm_args, vncarg); +- } ++ } else ++ /* ++ * Ensure that by default no vnc server is created. ++ */ ++ flexarray_append_pair(dm_args, "-vnc", "none"); ++ ++ /* ++ * Ensure that by default no display backend is created. Further ++ * options given below might then enable more. ++ */ ++ flexarray_append_pair(dm_args, "-display", "none"); + + if (sdl) { + flexarray_append(dm_args, "-sdl"); +-- +2.1.4 + |