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authorLennart Poettering <lennart@poettering.net>2013-04-15 14:05:00 +0200
committerLennart Poettering <lennart@poettering.net>2013-04-15 14:05:03 +0200
commit6c03089c32c251d823173bda4d809a9e643219f0 (patch)
tree8dc4afd1fe07208b30f5849954404b30b209c660
parent4a875b6133c9ef0e984547f7ce3b09356be4f7bc (diff)
bus: handle env vars safely
Make sure that our library is safe for usage in SUID programs when it comes to env var handling
-rw-r--r--src/libsystemd-bus/sd-bus.c7
-rw-r--r--src/shared/cgroup-util.c141
-rw-r--r--src/shared/cgroup-util.h6
-rw-r--r--src/test/test-cgroup-util.c76
4 files changed, 162 insertions, 68 deletions
diff --git a/src/libsystemd-bus/sd-bus.c b/src/libsystemd-bus/sd-bus.c
index f2dd81235f..c7511c32d2 100644
--- a/src/libsystemd-bus/sd-bus.c
+++ b/src/libsystemd-bus/sd-bus.c
@@ -31,6 +31,7 @@
#include "macro.h"
#include "strv.h"
#include "set.h"
+#include "missing.h"
#include "sd-bus.h"
#include "bus-internal.h"
@@ -841,7 +842,7 @@ int sd_bus_open_system(sd_bus **ret) {
if (r < 0)
return r;
- e = getenv("DBUS_SYSTEM_BUS_ADDRESS");
+ e = secure_getenv("DBUS_SYSTEM_BUS_ADDRESS");
if (e) {
r = sd_bus_set_address(b, e);
if (r < 0)
@@ -879,13 +880,13 @@ int sd_bus_open_user(sd_bus **ret) {
if (r < 0)
return r;
- e = getenv("DBUS_SESSION_BUS_ADDRESS");
+ e = secure_getenv("DBUS_SESSION_BUS_ADDRESS");
if (e) {
r = sd_bus_set_address(b, e);
if (r < 0)
goto fail;
} else {
- e = getenv("XDG_RUNTIME_DIR");
+ e = secure_getenv("XDG_RUNTIME_DIR");
if (!e) {
r = -ENOENT;
goto fail;
diff --git a/src/shared/cgroup-util.c b/src/shared/cgroup-util.c
index c17e1d4d1b..075260783c 100644
--- a/src/shared/cgroup-util.c
+++ b/src/shared/cgroup-util.c
@@ -1148,8 +1148,6 @@ int cg_get_user_path(char **path) {
char **cg_shorten_controllers(char **controllers) {
char **f, **t;
- controllers = strv_uniq(controllers);
-
if (!controllers)
return controllers;
@@ -1175,11 +1173,11 @@ char **cg_shorten_controllers(char **controllers) {
}
*t = NULL;
- return controllers;
+ return strv_uniq(controllers);
}
int cg_pid_get_cgroup(pid_t pid, char **root, char **cgroup) {
- char *cg_process, *cg_init, *p;
+ char *cg_process, *cg_init, *p, *q;
int r;
assert(pid >= 0);
@@ -1202,11 +1200,8 @@ int cg_pid_get_cgroup(pid_t pid, char **root, char **cgroup) {
else if (streq(cg_init, "/"))
cg_init[0] = 0;
- if (startswith(cg_process, cg_init))
- p = cg_process + strlen(cg_init);
- else
- p = cg_process;
-
+ q = startswith(cg_process, cg_init);
+ p = q ? q : cg_process;
free(cg_init);
if (cgroup) {
@@ -1230,84 +1225,126 @@ int cg_pid_get_cgroup(pid_t pid, char **root, char **cgroup) {
return 0;
}
-static int instance_unit_from_cgroup(char *cgroup){
- char *at;
+/* non-static only for testing purposes */
+int cg_cgroup_to_unit(const char *cgroup, char **unit){
+ char *p, *e, *c, *s, *k;
assert(cgroup);
+ assert(unit);
- at = strstr(cgroup, "@.");
- if (at) {
- /* This is a templated service */
+ e = strchrnul(cgroup, '/');
+ c = strndupa(cgroup, e - cgroup);
- char *i;
- char _cleanup_free_ *i2 = NULL, *s = NULL;
+ /* Could this be a valid unit name? */
+ if (!unit_name_is_valid(c, true))
+ return -EINVAL;
- i = strchr(at, '/');
- if (!i || !i[1]) /* disallow empty instances */
+ if (!unit_name_is_template(c))
+ s = strdup(c);
+ else {
+ if (*e != '/')
return -EINVAL;
- s = strndup(at + 1, i - at - 1);
- i2 = strdup(i + 1);
- if (!s || !i2)
- return -ENOMEM;
+ e += strspn(e, "/");
+ p = strchrnul(e, '/');
- strcpy(at + 1, i2);
- strcat(at + 1, s);
+ /* Don't allow empty instance strings */
+ if (p == e)
+ return -EINVAL;
+
+ k = strndupa(e, p - e);
+
+ s = unit_name_replace_instance(c, k);
}
+ if (!s)
+ return -ENOMEM;
+
+ *unit = s;
return 0;
}
-/* non-static only for testing purposes */
-int cgroup_to_unit(char *cgroup, char **unit){
+int cg_path_get_unit(const char *path, char **unit) {
+ const char *e;
+
+ assert(path);
+ assert(unit);
+
+ e = path_startswith(path, "/system/");
+ if (!e)
+ return -ENOENT;
+
+ return cg_cgroup_to_unit(e, unit);
+}
+
+int cg_pid_get_unit(pid_t pid, char **unit) {
+ char _cleanup_free_ *cgroup = NULL;
int r;
- char *p;
- assert(cgroup);
assert(unit);
- r = instance_unit_from_cgroup(cgroup);
+ r = cg_pid_get_cgroup(pid, NULL, &cgroup);
if (r < 0)
return r;
- p = strrchr(cgroup, '/');
- assert(p);
+ return cg_path_get_unit(cgroup, unit);
+}
- r = unit_name_is_valid(p + 1, true);
- if (!r)
- return -EINVAL;
+static const char *skip_label(const char *e) {
+ assert(e);
- *unit = strdup(p + 1);
- if (!*unit)
- return -ENOMEM;
+ e += strspn(e, "/");
+ e = strchr(e, '/');
+ if (!e)
+ return NULL;
- return 0;
+ e += strspn(e, "/");
+ return e;
}
-static int cg_pid_get(const char *prefix, pid_t pid, char **unit) {
- int r;
- char _cleanup_free_ *cgroup = NULL;
+int cg_path_get_user_unit(const char *path, char **unit) {
+ const char *e;
- assert(pid >= 0);
+ assert(path);
assert(unit);
- r = cg_pid_get_cgroup(pid, NULL, &cgroup);
- if (r < 0)
- return r;
+ /* We always have to parse the path from the beginning as unit
+ * cgroups might have arbitrary child cgroups and we shouldn't get
+ * confused by those */
- if (!startswith(cgroup, prefix))
+ e = path_startswith(path, "/user/");
+ if (!e)
return -ENOENT;
- r = cgroup_to_unit(cgroup, unit);
- return r;
-}
+ /* Skip the user name */
+ e = skip_label(e);
+ if (!e)
+ return -ENOENT;
-int cg_pid_get_unit(pid_t pid, char **unit) {
- return cg_pid_get("/system/", pid, unit);
+ /* Skip the session ID */
+ e = skip_label(e);
+ if (!e)
+ return -ENOENT;
+
+ /* Skip the systemd cgroup */
+ e = skip_label(e);
+ if (!e)
+ return -ENOENT;
+
+ return cg_cgroup_to_unit(e, unit);
}
int cg_pid_get_user_unit(pid_t pid, char **unit) {
- return cg_pid_get("/user/", pid, unit);
+ char _cleanup_free_ *cgroup = NULL;
+ int r;
+
+ assert(unit);
+
+ r = cg_pid_get_cgroup(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_user_unit(cgroup, unit);
}
int cg_controller_from_attr(const char *attr, char **controller) {
diff --git a/src/shared/cgroup-util.h b/src/shared/cgroup-util.h
index 06c6bfb2e3..123f72c69f 100644
--- a/src/shared/cgroup-util.h
+++ b/src/shared/cgroup-util.h
@@ -69,11 +69,15 @@ int cg_is_empty_by_spec(const char *spec, bool ignore_self);
int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_self);
int cg_get_user_path(char **path);
+
+int cg_path_get_unit(const char *path, char **unit);
+int cg_path_get_user_unit(const char *path, char **unit);
+
int cg_pid_get_cgroup(pid_t pid, char **root, char **cgroup);
int cg_pid_get_unit(pid_t pid, char **unit);
int cg_pid_get_user_unit(pid_t pid, char **unit);
-int cgroup_to_unit(char *cgroup, char **unit);
+int cg_cgroup_to_unit(const char *cgroup, char **unit);
char **cg_shorten_controllers(char **controllers);
diff --git a/src/test/test-cgroup-util.c b/src/test/test-cgroup-util.c
index b30bf23a80..8e24d1ceca 100644
--- a/src/test/test-cgroup-util.c
+++ b/src/test/test-cgroup-util.c
@@ -1,27 +1,79 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2013 Zbigniew Jędrzejewski-Szmek
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
#include <assert.h>
#include "util.h"
#include "cgroup-util.h"
-#define check_c_t_u(path, code, result) \
-{ \
- char a[] = path; \
- char *unit = NULL; \
- assert_se(cgroup_to_unit(a, &unit) == code); \
- assert(code < 0 || streq(unit, result)); \
-}
+static void check_c_t_u(const char *path, int code, const char *result) {
+ _cleanup_free_ char *unit = NULL;
+ assert_se(cg_cgroup_to_unit(path, &unit) == code);
+ assert_se(streq_ptr(unit, result));
+}
static void test_cgroup_to_unit(void) {
- check_c_t_u("/system/getty@.service/tty2", 0, "getty@tty2.service");
- check_c_t_u("/system/getty@.service/", -EINVAL, "getty@tty2.service");
- check_c_t_u("/system/getty@.service", -EINVAL, "getty@tty2.service");
- check_c_t_u("/system/getty.service", 0, "getty.service");
- check_c_t_u("/system/getty", -EINVAL, "getty.service");
+ check_c_t_u("getty@.service/tty2", 0, "getty@tty2.service");
+ check_c_t_u("getty@.service/tty2/xxx", 0, "getty@tty2.service");
+ check_c_t_u("getty@.service/", -EINVAL, NULL);
+ check_c_t_u("getty@.service", -EINVAL, NULL);
+ check_c_t_u("getty.service", 0, "getty.service");
+ check_c_t_u("getty", -EINVAL, NULL);
+}
+
+static void check_p_g_u(const char *path, int code, const char *result) {
+ _cleanup_free_ char *unit = NULL;
+
+ assert_se(cg_path_get_unit(path, &unit) == code);
+ assert_se(streq_ptr(unit, result));
+}
+
+static void check_p_g_u_u(const char *path, int code, const char *result) {
+ _cleanup_free_ char *unit = NULL;
+
+ assert_se(cg_path_get_user_unit(path, &unit) == code);
+ assert_se(streq_ptr(unit, result));
+}
+
+static void test_path_get_unit(void) {
+ check_p_g_u("/system/foobar.service/sdfdsaf", 0, "foobar.service");
+ check_p_g_u("/system/getty@.service/tty5", 0, "getty@tty5.service");
+ check_p_g_u("/system/getty@.service/tty5/aaa/bbb", 0, "getty@tty5.service");
+ check_p_g_u("/system/getty@.service/tty5/", 0, "getty@tty5.service");
+ check_p_g_u("/system/getty@tty6.service/tty5", 0, "getty@tty6.service");
+ check_p_g_u("sadfdsafsda", -ENOENT, NULL);
+ check_p_g_u("/system/getty####@tty6.service/tty5", -EINVAL, NULL);
+
+ check_p_g_u_u("/user/lennart/2/systemd-21548/foobar.service", 0, "foobar.service");
+ check_p_g_u_u("/user/lennart/2/systemd-21548/foobar.service/waldo", 0, "foobar.service");
+ check_p_g_u_u("/user/lennart/2/systemd-21548/foobar.service/waldo/uuuux", 0, "foobar.service");
+ check_p_g_u_u("/user/lennart/2/systemd-21548/waldo/waldo/uuuux", -EINVAL, NULL);
+ check_p_g_u_u("/user/lennart/2/foobar.service", -ENOENT, NULL);
+ check_p_g_u_u("/user/lennart/2/systemd-21548/foobar@.service/pie/pa/po", 0, "foobar@pie.service");
}
int main(void) {
test_cgroup_to_unit();
+ test_path_get_unit();
return 0;
}