Commit 5954c074 authored by Lennart Poettering's avatar Lennart Poettering

cgroup: do not allow manipulating the cgroup path of units within the systemd:/system subtree

parent aa96c6cb
......@@ -26,6 +26,10 @@ Fedora 19:
Features:
* handle named vs controller hierarchies correctly in cg_pid_get_path()
* add nspawn@.service
* investigate endianess issues of UUID vs. GUID
* see if we can fix https://bugs.freedesktop.org/show_bug.cgi?id=63672
......@@ -57,9 +61,6 @@ Features:
* make sure cg_pid_get_path() works properly for co-mounted controllers
* explicitly disallow changing the cgroup path of units in the
name=systemd hierarchy, unless it is outside of /system
* test/:
- add 'set -e' to scripts in test/
- make stuff in test/ work with separate output dir
......
......@@ -1977,10 +1977,16 @@ static int unit_add_cgroup(Unit *u, CGroupBonding *b) {
}
char *unit_default_cgroup_path(Unit *u) {
_cleanup_free_ char *escaped_instance = NULL;
assert(u);
escaped_instance = cg_escape(u->id);
if (!escaped_instance)
return NULL;
if (u->instance) {
_cleanup_free_ char *t = NULL, *escaped_template = NULL, *escaped_instance = NULL;
_cleanup_free_ char *t = NULL, *escaped_template = NULL;
t = unit_name_template(u->id);
if (!t)
......@@ -1990,20 +1996,9 @@ char *unit_default_cgroup_path(Unit *u) {
if (!escaped_template)
return NULL;
escaped_instance = cg_escape(u->id);
if (!escaped_instance)
return NULL;
return strjoin(u->manager->cgroup_hierarchy, "/", escaped_template, "/", escaped_instance, NULL);
} else {
_cleanup_free_ char *escaped = NULL;
escaped = cg_escape(u->id);
if (!escaped)
return NULL;
return strjoin(u->manager->cgroup_hierarchy, "/", escaped, NULL);
}
} else
return strjoin(u->manager->cgroup_hierarchy, "/", escaped_instance, NULL);
}
int unit_add_cgroup_from_text(Unit *u, const char *name, bool overwrite, CGroupBonding **ret) {
......@@ -2025,7 +2020,7 @@ int unit_add_cgroup_from_text(Unit *u, const char *name, bool overwrite, CGroupB
}
if (!controller) {
controller = strdup(SYSTEMD_CGROUP_CONTROLLER);
controller = strdup("systemd");
ours = true;
}
......@@ -2035,6 +2030,16 @@ int unit_add_cgroup_from_text(Unit *u, const char *name, bool overwrite, CGroupB
return log_oom();
}
if (streq(controller, "systemd")) {
/* Within the systemd unit hierarchy we do not allow changes. */
if (path_startswith(path, "/system")) {
log_warning_unit(u->id, "Manipulating the systemd:/system cgroup hierarchy is not permitted.");
free(path);
free(controller);
return -EPERM;
}
}
b = cgroup_bonding_find_list(u->cgroup_bondings, controller);
if (b) {
if (streq(path, b->path)) {
......
......@@ -916,6 +916,7 @@ int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_
int cg_split_spec(const char *spec, char **controller, char **path) {
const char *e;
char *t = NULL, *u = NULL;
_cleanup_free_ char *v = NULL;
assert(spec);
......@@ -928,6 +929,7 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
if (!t)
return -ENOMEM;
path_kill_slashes(t);
*path = t;
}
......@@ -943,7 +945,7 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
return -EINVAL;
if (controller) {
t = strdup(spec);
t = strdup(normalize_controller(spec));
if (!t)
return -ENOMEM;
......@@ -956,7 +958,10 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
return 0;
}
t = strndup(spec, e-spec);
v = strndup(spec, e-spec);
if (!v)
return -ENOMEM;
t = strdup(normalize_controller(v));
if (!t)
return -ENOMEM;
if (!cg_controller_is_valid(t, true)) {
......@@ -969,12 +974,15 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
free(t);
return -ENOMEM;
}
if (!path_is_safe(u)) {
if (!path_is_safe(u) ||
!path_is_absolute(u)) {
free(t);
free(u);
return -EINVAL;
}
path_kill_slashes(u);
if (controller)
*controller = t;
else
......@@ -993,7 +1001,6 @@ int cg_join_spec(const char *controller, const char *path, char **spec) {
assert(path);
if (!controller)
controller = "systemd";
else {
......@@ -1010,6 +1017,8 @@ int cg_join_spec(const char *controller, const char *path, char **spec) {
if (!s)
return -ENOMEM;
path_kill_slashes(s + strlen(controller) + 1);
*spec = s;
return 0;
}
......@@ -1029,6 +1038,7 @@ int cg_mangle_path(const char *path, char **result) {
if (!t)
return -ENOMEM;
path_kill_slashes(t);
*result = t;
return 0;
}
......
......@@ -28,6 +28,21 @@
#include "set.h"
#include "def.h"
/*
* General rules:
*
* We accept named hierarchies in the syntax "foo" and "name=foo".
*
* We expect that named hierarchies do not conflict in name with a
* kernel hierarchy, modulo the "name=" prefix.
*
* We always generate "normalized" controller names, i.e. without the
* "name=" prefix.
*
* We require absolute cgroup paths. When returning, we will always
* generate paths with multiple adjacent / removed.
*/
int cg_enumerate_processes(const char *controller, const char *path, FILE **_f);
int cg_enumerate_tasks(const char *controller, const char *path, FILE **_f);
int cg_read_pid(FILE *f, pid_t *_pid);
......
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