diff options
| author | Tom Gundersen <teg@jklm.no> | 2014-06-01 22:01:20 +0100 |
|---|---|---|
| committer | Tom Gundersen <teg@jklm.no> | 2014-06-03 10:40:28 +0200 |
| commit | 682265d5e2157882861b0091c6b81fa92699b72a (patch) | |
| tree | dde1a99c7c4df2c673f4dabe02b7b6ba8409aede | |
| parent | 0bbea466dcafc0ff51811a3bc451e983c02e63bf (diff) | |
resolved: run as unpriviliged "systemd-resolve" user
This service is not yet network facing, but let's prepare nonetheless.
Currently all caps are dropped, but some may need to be kept in the
future.
| -rw-r--r-- | Makefile.am | 1 | ||||
| -rw-r--r-- | README | 5 | ||||
| -rw-r--r-- | src/resolve/resolved.c | 20 | ||||
| -rw-r--r-- | units/systemd-resolved.service.in | 2 |
4 files changed, 25 insertions, 3 deletions
diff --git a/Makefile.am b/Makefile.am index b14a6c339..de4242491 100644 --- a/Makefile.am +++ b/Makefile.am @@ -4215,6 +4215,7 @@ CLEANFILES += \ src/resolve/resolved-gperf.c systemd_resolved_LDADD = \ + libsystemd-capability.la \ libsystemd-network.la \ libsystemd-label.la \ libsystemd-internal.la \ @@ -193,6 +193,11 @@ USERS AND GROUPS: facing service will drop privileges (with the exception of CAP_NET_*) and assumed this uid/gid for security reasons. + The name resolution daemon requires the "systemd-resolve" + system user and group to exist. During execution this network + facing service will drop privileges and assume this uid/gid + for security reasons. + WARNINGS: systemd will warn you during boot if /etc/mtab is not a symlink to /proc/mounts. Please ensure that /etc/mtab is a diff --git a/src/resolve/resolved.c b/src/resolve/resolved.c index 2eaff60fc..f61b70f46 100644 --- a/src/resolve/resolved.c +++ b/src/resolve/resolved.c @@ -25,9 +25,13 @@ #include "resolved.h" #include "mkdir.h" +#include "capability.h" int main(int argc, char *argv[]) { _cleanup_manager_free_ Manager *m = NULL; + const char *user = "systemd-resolve"; + uid_t uid; + gid_t gid; int r; log_set_target(LOG_TARGET_AUTO); @@ -42,11 +46,23 @@ int main(int argc, char *argv[]) { goto out; } + r = get_user_creds(&user, &uid, &gid, NULL, NULL); + if (r < 0) { + log_error("Cannot resolve user name %s: %s", user, strerror(-r)); + goto out; + } + /* Always create the directory where resolv.conf will live */ - r = mkdir_label("/run/systemd/resolve", 0755); - if (r < 0) + r = mkdir_safe_label("/run/systemd/resolve", 0755, uid, gid); + if (r < 0) { log_error("Could not create runtime directory: %s", strerror(-r)); + goto out; + } + + r = drop_privileges(uid, gid, 0); + if (r < 0) + goto out; r = manager_new(&m); if (r < 0) { diff --git a/units/systemd-resolved.service.in b/units/systemd-resolved.service.in index f4bbb7c16..9d422ca7f 100644 --- a/units/systemd-resolved.service.in +++ b/units/systemd-resolved.service.in @@ -15,7 +15,7 @@ Type=notify Restart=always RestartSec=0 ExecStart=@rootlibexecdir@/systemd-resolved -CapabilityBoundingSet= +CapabilityBoundingSet=CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_DAC_OVERRIDE CAP_FOWNER [Install] WantedBy=multi-user.target |