diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c index e6e12d8927..0db5f13553 100644 --- a/tools/libxl/libxl_dm.c +++ b/tools/libxl/libxl_dm.c @@ -363,6 +363,20 @@ int libxl__domain_device_construct_rdm(libxl__gc *gc, return ERROR_FAIL; } +/* XSA-180 / CVE-2014-3672 + * + * The QEMU shipped with Xen has a bodge. It checks for + * XEN_QEMU_CONSOLE_LIMIT to see how much data QEMU is allowed + * to write to stderr. We set that to 1MB if it is not set by + * system administrator. + */ +static void libxl__set_qemu_env_for_xsa_180(libxl__gc *gc, + flexarray_t *dm_envs) +{ + if (getenv("XEN_QEMU_CONSOLE_LIMIT")) return; + flexarray_append_pair(dm_envs, "XEN_QEMU_CONSOLE_LIMIT", "1048576"); +} + const libxl_vnc_info *libxl__dm_vnc(const libxl_domain_config *guest_config) { const libxl_vnc_info *vnc = NULL; @@ -413,6 +427,8 @@ static int libxl__build_device_model_args_old(libxl__gc *gc, dm_args = flexarray_make(gc, 16, 1); dm_envs = flexarray_make(gc, 16, 1); + libxl__set_qemu_env_for_xsa_180(gc, dm_envs); + flexarray_vappend(dm_args, dm, "-d", libxl__sprintf(gc, "%d", domid), NULL); @@ -726,6 +742,8 @@ static int libxl__build_device_model_args_new(libxl__gc *gc, dm_args = flexarray_make(gc, 16, 1); dm_envs = flexarray_make(gc, 16, 1); + libxl__set_qemu_env_for_xsa_180(gc, dm_envs); + flexarray_vappend(dm_args, dm, "-xen-domid", libxl__sprintf(gc, "%d", guest_domid), NULL); @@ -1872,8 +1890,8 @@ static void device_model_spawn_outcome(libxl__egc *egc, void libxl__spawn_qdisk_backend(libxl__egc *egc, libxl__dm_spawn_state *dmss) { STATE_AO_GC(dmss->spawn.ao); - flexarray_t *dm_args; - char **args; + flexarray_t *dm_args, *dm_envs; + char **args, **envs; const char *dm; int logfile_w, null = -1, rc; uint32_t domid = dmss->guest_domid; @@ -1882,6 +1900,8 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, libxl__dm_spawn_state *dmss) dm = qemu_xen_path(gc); dm_args = flexarray_make(gc, 15, 1); + dm_envs = flexarray_make(gc, 1, 1); + flexarray_vappend(dm_args, dm, "-xen-domid", GCSPRINTF("%d", domid), NULL); flexarray_append(dm_args, "-xen-attach"); @@ -1895,6 +1915,9 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, libxl__dm_spawn_state *dmss) flexarray_append(dm_args, NULL); args = (char **) flexarray_contents(dm_args); + libxl__set_qemu_env_for_xsa_180(gc, dm_envs); + envs = (char **) flexarray_contents(dm_envs); + logfile_w = libxl__create_qemu_logfile(gc, GCSPRINTF("qdisk-%u", domid)); if (logfile_w < 0) { rc = logfile_w; @@ -1932,7 +1955,7 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, libxl__dm_spawn_state *dmss) goto error; if (!rc) { /* inner child */ setsid(); - libxl__exec(gc, null, logfile_w, logfile_w, dm, args, NULL); + libxl__exec(gc, null, logfile_w, logfile_w, dm, args, envs); } return;