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-rw-r--r--src/nss-systemd/nss-systemd.c262
1 files changed, 176 insertions, 86 deletions
diff --git a/src/nss-systemd/nss-systemd.c b/src/nss-systemd/nss-systemd.c
index 7078c0c50c..17d04e958d 100644
--- a/src/nss-systemd/nss-systemd.c
+++ b/src/nss-systemd/nss-systemd.c
@@ -21,11 +21,14 @@
#include "sd-bus.h"
+#include "alloc-util.h"
#include "bus-common-errors.h"
#include "env-util.h"
+#include "fs-util.h"
#include "macro.h"
#include "nss-util.h"
#include "signal-util.h"
+#include "stdio-util.h"
#include "string-util.h"
#include "user-util.h"
#include "util.h"
@@ -75,15 +78,50 @@ static const struct group nobody_group = {
NSS_GETPW_PROTOTYPES(systemd);
NSS_GETGR_PROTOTYPES(systemd);
+static int direct_lookup_name(const char *name, uid_t *ret) {
+ _cleanup_free_ char *s = NULL;
+ const char *path;
+ int r;
+
+ assert(name);
+
+ /* Normally, we go via the bus to resolve names. That has the benefit that it is available from any mount
+ * namespace and subject to proper authentication. However, there's one problem: if our module is called from
+ * dbus-daemon itself we really can't use D-Bus to communicate. In this case, resort to a client-side hack,
+ * and look for the dynamic names directly. This is pretty ugly, but breaks the cyclic dependency. */
+
+ path = strjoina("/run/systemd/dynamic-uid/direct:", name);
+ r = readlink_malloc(path, &s);
+ if (r < 0)
+ return r;
+
+ return parse_uid(s, ret);
+}
+
+static int direct_lookup_uid(uid_t uid, char **ret) {
+ char path[strlen("/run/systemd/dynamic-uid/direct:") + DECIMAL_STR_MAX(uid_t) + 1], *s;
+ int r;
+
+ xsprintf(path, "/run/systemd/dynamic-uid/direct:" UID_FMT, uid);
+
+ r = readlink_malloc(path, &s);
+ if (r < 0)
+ return r;
+ if (!valid_user_group_name(s)) { /* extra safety check */
+ free(s);
+ return -EINVAL;
+ }
+
+ *ret = s;
+ return 0;
+}
+
enum nss_status _nss_systemd_getpwnam_r(
const char *name,
struct passwd *pwd,
char *buffer, size_t buflen,
int *errnop) {
- _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
- _cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
- _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
uint32_t translated;
size_t l;
int r;
@@ -114,30 +152,45 @@ enum nss_status _nss_systemd_getpwnam_r(
if (getenv_bool("SYSTEMD_NSS_DYNAMIC_BYPASS") > 0)
goto not_found;
- r = sd_bus_open_system(&bus);
- if (r < 0)
- goto fail;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0) {
- r = sd_bus_call_method(bus,
- "org.freedesktop.systemd1",
- "/org/freedesktop/systemd1",
- "org.freedesktop.systemd1.Manager",
- "LookupDynamicUserByName",
- &error,
- &reply,
- "s",
- name);
- if (r < 0) {
- if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ /* Access the dynamic UID allocation directly if we are called from dbus-daemon, see above. */
+ r = direct_lookup_name(name, (uid_t*) &translated);
+ if (r == -ENOENT)
goto not_found;
-
- goto fail;
+ if (r < 0)
+ goto fail;
+
+ } else {
+ _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
+ _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+
+ r = sd_bus_open_system(&bus);
+ if (r < 0)
+ goto fail;
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.systemd1",
+ "/org/freedesktop/systemd1",
+ "org.freedesktop.systemd1.Manager",
+ "LookupDynamicUserByName",
+ &error,
+ &reply,
+ "s",
+ name);
+ if (r < 0) {
+ if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ goto not_found;
+
+ goto fail;
+ }
+
+ r = sd_bus_message_read(reply, "u", &translated);
+ if (r < 0)
+ goto fail;
}
- r = sd_bus_message_read(reply, "u", &translated);
- if (r < 0)
- goto fail;
-
l = strlen(name);
if (buflen < l+1) {
*errnop = ENOMEM;
@@ -175,6 +228,7 @@ enum nss_status _nss_systemd_getpwuid_r(
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+ _cleanup_free_ char *direct = NULL;
const char *translated;
size_t l;
int r;
@@ -204,30 +258,42 @@ enum nss_status _nss_systemd_getpwuid_r(
if (getenv_bool("SYSTEMD_NSS_DYNAMIC_BYPASS") > 0)
goto not_found;
- r = sd_bus_open_system(&bus);
- if (r < 0)
- goto fail;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0) {
- r = sd_bus_call_method(bus,
- "org.freedesktop.systemd1",
- "/org/freedesktop/systemd1",
- "org.freedesktop.systemd1.Manager",
- "LookupDynamicUserByUID",
- &error,
- &reply,
- "u",
- (uint32_t) uid);
- if (r < 0) {
- if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ r = direct_lookup_uid(uid, &direct);
+ if (r == -ENOENT)
goto not_found;
-
- goto fail;
+ if (r < 0)
+ goto fail;
+
+ translated = direct;
+
+ } else {
+ r = sd_bus_open_system(&bus);
+ if (r < 0)
+ goto fail;
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.systemd1",
+ "/org/freedesktop/systemd1",
+ "org.freedesktop.systemd1.Manager",
+ "LookupDynamicUserByUID",
+ &error,
+ &reply,
+ "u",
+ (uint32_t) uid);
+ if (r < 0) {
+ if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ goto not_found;
+
+ goto fail;
+ }
+
+ r = sd_bus_message_read(reply, "s", &translated);
+ if (r < 0)
+ goto fail;
}
- r = sd_bus_message_read(reply, "s", &translated);
- if (r < 0)
- goto fail;
-
l = strlen(translated) + 1;
if (buflen < l) {
*errnop = ENOMEM;
@@ -262,9 +328,6 @@ enum nss_status _nss_systemd_getgrnam_r(
char *buffer, size_t buflen,
int *errnop) {
- _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
- _cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
- _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
uint32_t translated;
size_t l;
int r;
@@ -294,30 +357,45 @@ enum nss_status _nss_systemd_getgrnam_r(
if (getenv_bool("SYSTEMD_NSS_DYNAMIC_BYPASS") > 0)
goto not_found;
- r = sd_bus_open_system(&bus);
- if (r < 0)
- goto fail;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0) {
- r = sd_bus_call_method(bus,
- "org.freedesktop.systemd1",
- "/org/freedesktop/systemd1",
- "org.freedesktop.systemd1.Manager",
- "LookupDynamicUserByName",
- &error,
- &reply,
- "s",
- name);
- if (r < 0) {
- if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ /* Access the dynamic GID allocation directly if we are called from dbus-daemon, see above. */
+ r = direct_lookup_name(name, (uid_t*) &translated);
+ if (r == -ENOENT)
goto not_found;
-
- goto fail;
+ if (r < 0)
+ goto fail;
+ } else {
+
+ _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
+ _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+
+ r = sd_bus_open_system(&bus);
+ if (r < 0)
+ goto fail;
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.systemd1",
+ "/org/freedesktop/systemd1",
+ "org.freedesktop.systemd1.Manager",
+ "LookupDynamicUserByName",
+ &error,
+ &reply,
+ "s",
+ name);
+ if (r < 0) {
+ if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ goto not_found;
+
+ goto fail;
+ }
+
+ r = sd_bus_message_read(reply, "u", &translated);
+ if (r < 0)
+ goto fail;
}
- r = sd_bus_message_read(reply, "u", &translated);
- if (r < 0)
- goto fail;
-
l = sizeof(char*) + strlen(name) + 1;
if (buflen < l) {
*errnop = ENOMEM;
@@ -353,6 +431,7 @@ enum nss_status _nss_systemd_getgrgid_r(
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+ _cleanup_free_ char *direct = NULL;
const char *translated;
size_t l;
int r;
@@ -382,30 +461,41 @@ enum nss_status _nss_systemd_getgrgid_r(
if (getenv_bool("SYSTEMD_NSS_DYNAMIC_BYPASS") > 0)
goto not_found;
- r = sd_bus_open_system(&bus);
- if (r < 0)
- goto fail;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0) {
- r = sd_bus_call_method(bus,
- "org.freedesktop.systemd1",
- "/org/freedesktop/systemd1",
- "org.freedesktop.systemd1.Manager",
- "LookupDynamicUserByUID",
- &error,
- &reply,
- "u",
- (uint32_t) gid);
- if (r < 0) {
- if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ r = direct_lookup_uid(gid, &direct);
+ if (r == -ENOENT)
goto not_found;
-
- goto fail;
+ if (r < 0)
+ goto fail;
+
+ translated = direct;
+ } else {
+ r = sd_bus_open_system(&bus);
+ if (r < 0)
+ goto fail;
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.systemd1",
+ "/org/freedesktop/systemd1",
+ "org.freedesktop.systemd1.Manager",
+ "LookupDynamicUserByUID",
+ &error,
+ &reply,
+ "u",
+ (uint32_t) gid);
+ if (r < 0) {
+ if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_DYNAMIC_USER))
+ goto not_found;
+
+ goto fail;
+ }
+
+ r = sd_bus_message_read(reply, "s", &translated);
+ if (r < 0)
+ goto fail;
}
- r = sd_bus_message_read(reply, "s", &translated);
- if (r < 0)
- goto fail;
-
l = sizeof(char*) + strlen(translated) + 1;
if (buflen < l) {
*errnop = ENOMEM;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-22 18:38:25 +0000