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cgroup: always validate cgroup controller names 

Let's better be safe than sorry.
This commit is contained in:
Lennart Poettering 2013-04-24 19:01:29 -03:00
parent e10375f2c0
commit 78edb35ab4
6 changed files with 89 additions and 35 deletions
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4
TODO
View File

@ -57,10 +57,6 @@ Features:
* add s.th. like "systemctl set-log-level debug"
* sd-login: allow enumerating machines and add inotify iface
* cgroup-util: verify syntax of cgroup controllers
* cgtop: make cgtop useful in a container
* make sure cg_pid_get_path() works properly for co-mounted controllers

26
src/core/unit.c
View File

@ -1938,7 +1938,7 @@ char *unit_dbus_path(Unit *u) {
return unit_dbus_path_from_name(u->id);
}
int unit_add_cgroup(Unit *u, CGroupBonding *b) {
static int unit_add_cgroup(Unit *u, CGroupBonding *b) {
int r;
assert(u);
@ -2100,6 +2100,9 @@ static int unit_add_one_default_cgroup(Unit *u, const char *controller) {
assert(u);
if (controller && !cg_controller_is_valid(controller, true))
return -EINVAL;
if (!controller)
controller = SYSTEMD_CGROUP_CONTROLLER;
@ -2202,13 +2205,15 @@ int unit_add_cgroup_attribute(
controller = c;
}
if (!controller || streq(controller, SYSTEMD_CGROUP_CONTROLLER))
if (!controller ||
streq(controller, SYSTEMD_CGROUP_CONTROLLER) ||
streq(controller, "systemd"))
return -EINVAL;
if (!filename_is_safe(name))
return -EINVAL;
if (!filename_is_safe(controller))
if (!cg_controller_is_valid(controller, false))
return -EINVAL;
/* Check if this attribute already exists. Note that we will
@ -2276,42 +2281,39 @@ int unit_add_cgroup_attribute(
}
int unit_load_related_unit(Unit *u, const char *type, Unit **_found) {
char *t;
_cleanup_free_ char *t = NULL;
int r;
assert(u);
assert(type);
assert(_found);
if (!(t = unit_name_change_suffix(u->id, type)))
t = unit_name_change_suffix(u->id, type);
if (!t)
return -ENOMEM;
assert(!unit_has_name(u, t));
r = manager_load_unit(u->manager, t, NULL, NULL, _found);
free(t);
assert(r < 0 || *_found != u);
return r;
}
int unit_get_related_unit(Unit *u, const char *type, Unit **_found) {
_cleanup_free_ char *t = NULL;
Unit *found;
char *t;
assert(u);
assert(type);
assert(_found);
if (!(t = unit_name_change_suffix(u->id, type)))
t = unit_name_change_suffix(u->id, type);
if (!t)
return -ENOMEM;
assert(!unit_has_name(u, t));
found = manager_get_unit(u->manager, t);
free(t);
if (!found)
return -ENOENT;

1
src/core/unit.h
View File

@ -450,7 +450,6 @@ int unit_add_two_dependencies_by_name_inverse(Unit *u, UnitDependency d, UnitDep
int unit_add_exec_dependencies(Unit *u, ExecContext *c);
int unit_add_cgroup(Unit *u, CGroupBonding *b);
int unit_add_cgroup_from_text(Unit *u, const char *name, bool overwrite, CGroupBonding **ret);
int unit_add_default_cgroups(Unit *u);
CGroupBonding* unit_get_default_cgroup(Unit *u);

77
src/shared/cgroup-util.c
View File

@ -510,6 +510,9 @@ int cg_get_path(const char *controller, const char *path, const char *suffix, ch
assert(fs);
if (controller && !cg_controller_is_valid(controller, true))
return -EINVAL;
if (_unlikely_(!good)) {
int r;
@ -546,7 +549,7 @@ int cg_get_path_and_check(const char *controller, const char *path, const char *
assert(fs);
if (isempty(controller))
if (!cg_controller_is_valid(controller, true))
return -EINVAL;
/* Normalize the controller syntax */
@ -741,6 +744,9 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
assert(path);
assert(pid >= 0);
if (controller && !cg_controller_is_valid(controller, true))
return -EINVAL;
if (!controller)
controller = SYSTEMD_CGROUP_CONTROLLER;
@ -933,7 +939,7 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
e = strchr(spec, ':');
if (!e) {
if (!filename_is_safe(spec))
if (!cg_controller_is_valid(spec, true))
return -EINVAL;
if (controller) {
@ -953,7 +959,7 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
t = strndup(spec, e-spec);
if (!t)
return -ENOMEM;
if (!filename_is_safe(t)) {
if (!cg_controller_is_valid(t, true)) {
free(t);
return -EINVAL;
}
@ -987,18 +993,19 @@ int cg_join_spec(const char *controller, const char *path, char **spec) {
assert(path);
if (!controller)
controller = "systemd";
else if (controller[0] == 0 ||
strchr(controller, ':') ||
strchr(controller, '/'))
return -EINVAL;
else {
if (!cg_controller_is_valid(controller, true))
return -EINVAL;
controller = normalize_controller(controller);
}
if (!path_is_absolute(path))
return -EINVAL;
controller = normalize_controller(controller);
s = strjoin(controller, ":", path, NULL);
if (!s)
return -ENOMEM;
@ -1008,7 +1015,8 @@ int cg_join_spec(const char *controller, const char *path, char **spec) {
}
int cg_mangle_path(const char *path, char **result) {
char *t, *c, *p;
_cleanup_free_ char *c = NULL, *p = NULL;
char *t;
int r;
assert(path);
@ -1030,11 +1038,7 @@ int cg_mangle_path(const char *path, char **result) {
if (r < 0)
return r;
r = cg_get_path(c ? c : SYSTEMD_CGROUP_CONTROLLER, p ? p : "/", NULL, result);
free(c);
free(p);
return r;
return cg_get_path(c ? c : SYSTEMD_CGROUP_CONTROLLER, p ? p : "/", NULL, result);
}
int cg_get_system_path(char **path) {
@ -1138,14 +1142,20 @@ char **cg_shorten_controllers(char **controllers) {
p = normalize_controller(*f);
if (streq(*f, "systemd")) {
if (streq(p, "systemd")) {
free(*f);
continue;
}
if (!cg_controller_is_valid(p, true)) {
log_warning("Controller %s is not valid, removing from controllers list.", p);
free(*f);
continue;
}
r = check_hierarchy(p);
if (r < 0) {
log_debug("Controller %s is not available, removing from controllers list.", *f);
log_debug("Controller %s is not available, removing from controllers list.", p);
free(*f);
continue;
}
@ -1457,7 +1467,7 @@ int cg_controller_from_attr(const char *attr, char **controller) {
if (!c)
return -ENOMEM;
if (!filename_is_safe(c)) {
if (!cg_controller_is_valid(c, false)) {
free(c);
return -EINVAL;
}
@ -1517,3 +1527,34 @@ char *cg_unescape(const char *p) {
return (char*) p;
}
#define CONTROLLER_VALID \
"0123456789" \
"abcdefghijklmnopqrstuvwxyz" \
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
"_"
bool cg_controller_is_valid(const char *p, bool allow_named) {
const char *t, *s;
if (!p)
return false;
if (allow_named) {
s = startswith(p, "name=");
if (s)
p = s;
}
if (*p == 0 || *p == '_')
return false;
for (t = p; *t; t++)
if (!strchr(CONTROLLER_VALID, *t))
return false;
if (t - p > FILENAME_MAX)
return false;
return true;
}

2
src/shared/cgroup-util.h
View File

@ -96,3 +96,5 @@ int cg_controller_from_attr(const char *attr, char **controller);
char *cg_escape(const char *p);
char *cg_unescape(const char *p);
bool cg_controller_is_valid(const char *p, bool allow_named);

14
src/test/test-cgroup-util.c
View File

@ -153,6 +153,19 @@ static void test_escape(void) {
test_escape_one("_foobar", "__foobar");
}
static void test_controller_is_valid(void) {
assert_se(cg_controller_is_valid("foobar", false));
assert_se(cg_controller_is_valid("foo_bar", false));
assert_se(cg_controller_is_valid("name=foo", true));
assert_se(!cg_controller_is_valid("", false));
assert_se(!cg_controller_is_valid("name=", true));
assert_se(!cg_controller_is_valid("=", false));
assert_se(!cg_controller_is_valid("cpu,cpuacct", false));
assert_se(!cg_controller_is_valid("_", false));
assert_se(!cg_controller_is_valid("_foobar", false));
assert_se(!cg_controller_is_valid("tatü", false));
}
int main(void) {
test_path_decode_unit();
test_path_get_unit();
@ -160,6 +173,7 @@ int main(void) {
test_get_paths();
test_proc();
test_escape();
test_controller_is_valid();
return 0;
}