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authorLennart Poettering <lennart@poettering.net>2016-08-19 00:35:05 +0200
committerLennart Poettering <lennart@poettering.net>2016-08-19 00:52:00 +0200
commit6e32c03ed87e5dfd3857013e909e48b5e61564c1 (patch)
tree1721440ab440942ec23ea100e0002a85ecb9b591
parentfd63e712b2025d235ce4bfbb512fada10e2690b5 (diff)
nss-mymachines: avoid connecting to dbus from inside dbus-daemon
Inspired from the new logic in nss-systemd let's make sure we don't end up deadlocking in nss-mymachines either in case dbus-daemon tries to a look up a name and we want to connect to the bus. This case is much simpler though, as there's no point in resolving virtual machine UIDs by dbus-daemon as those should never be able to connect to the host's busses.
-rw-r--r--src/nss-mymachines/nss-mymachines.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/src/nss-mymachines/nss-mymachines.c b/src/nss-mymachines/nss-mymachines.c
index 8d57b26cbc..895f61c462 100644
--- a/src/nss-mymachines/nss-mymachines.c
+++ b/src/nss-mymachines/nss-mymachines.c
@@ -25,6 +25,7 @@
#include "alloc-util.h"
#include "bus-common-errors.h"
+#include "env-util.h"
#include "hostname-util.h"
#include "in-addr-util.h"
#include "macro.h"
@@ -434,6 +435,12 @@ enum nss_status _nss_mymachines_getpwnam_r(
if (!machine_name_is_valid(machine))
goto not_found;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0)
+ /* Make sure we can't deadlock if we are invoked by dbus-daemon. This way, it won't be able to resolve
+ * these UIDs, but that should be unproblematic as containers should never be able to connect to a bus
+ * running on the host. */
+ goto not_found;
+
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
@@ -514,6 +521,9 @@ enum nss_status _nss_mymachines_getpwuid_r(
if (uid < HOST_UID_LIMIT)
goto not_found;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0)
+ goto not_found;
+
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
@@ -605,6 +615,9 @@ enum nss_status _nss_mymachines_getgrnam_r(
if (!machine_name_is_valid(machine))
goto not_found;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0)
+ goto not_found;
+
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
@@ -682,6 +695,9 @@ enum nss_status _nss_mymachines_getgrgid_r(
if (gid < HOST_GID_LIMIT)
goto not_found;
+ if (getenv_bool("SYSTEMD_NSS_BYPASS_BUS") > 0)
+ goto not_found;
+
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;