bus: add new sd_bus_creds object to encapsulate process credentials

This way we can unify handling of credentials that are attached to
messages, or can be queried for bus name owners or connection peers.

This also adds the ability to extend incomplete credential information
with data from /proc,

Also, provide a convenience call that will automatically determine the
most appropriate credential object for an incoming message, by using the
the attached information if possible, the sending name information if
available and otherwise the peer's credentials.

1 files changed, 39 insertions, 22 deletions

diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c
index da9474dc51..84d84df59d 100644
--- a/src/libsystemd-bus/bus-kernel.c
+++ b/src/libsystemd-bus/bus-kernel.c
@@ -548,31 +548,48 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                         idx += d->memfd.size;
 
                 } else if (d->type == KDBUS_MSG_SRC_CREDS) {
-                        m->pid_starttime = d->creds.starttime / NSEC_PER_USEC;
-                        m->uid = d->creds.uid;
-                        m->gid = d->creds.gid;
-                        m->pid = d->creds.pid;
-                        m->tid = d->creds.tid;
-                        m->uid_valid = m->gid_valid = true;
+                        m->creds.pid_starttime = d->creds.starttime / NSEC_PER_USEC;
+                        m->creds.uid = d->creds.uid;
+                        m->creds.gid = d->creds.gid;
+                        m->creds.pid = d->creds.pid;
+                        m->creds.tid = d->creds.tid;
+                        m->creds.mask |= (SD_BUS_CREDS_UID|SD_BUS_CREDS_GID|SD_BUS_CREDS_PID|SD_BUS_CREDS_PID_STARTTIME|SD_BUS_CREDS_TID) & bus->creds_mask;
+
                 } else if (d->type == KDBUS_MSG_TIMESTAMP) {
                         m->realtime = d->timestamp.realtime_ns / NSEC_PER_USEC;
                         m->monotonic = d->timestamp.monotonic_ns / NSEC_PER_USEC;
-                } else if (d->type == KDBUS_MSG_SRC_PID_COMM)
-                        m->comm = d->str;
-                else if (d->type == KDBUS_MSG_SRC_TID_COMM)
-                        m->tid_comm = d->str;
-                else if (d->type == KDBUS_MSG_SRC_EXE)
-                        m->exe = d->str;
-                else if (d->type == KDBUS_MSG_SRC_CMDLINE) {
-                        m->cmdline = d->str;
-                        m->cmdline_length = l;
-                } else if (d->type == KDBUS_MSG_SRC_CGROUP)
-                        m->cgroup = d->str;
-                else if (d->type == KDBUS_MSG_SRC_AUDIT)
-                        m->audit = &d->audit;
-                else if (d->type == KDBUS_MSG_SRC_CAPS) {
-                        m->capability = d->data;
-                        m->capability_size = l;
+
+                } else if (d->type == KDBUS_MSG_SRC_PID_COMM) {
+                        m->creds.comm = d->str;
+                        m->creds.mask |= SD_BUS_CREDS_COMM & bus->creds_mask;
+
+                } else if (d->type == KDBUS_MSG_SRC_TID_COMM) {
+                        m->creds.tid_comm = d->str;
+                        m->creds.mask |= SD_BUS_CREDS_TID_COMM & bus->creds_mask;
+
+                } else if (d->type == KDBUS_MSG_SRC_EXE) {
+                        m->creds.exe = d->str;
+                        m->creds.mask |= SD_BUS_CREDS_EXE & bus->creds_mask;
+
+                } else if (d->type == KDBUS_MSG_SRC_CMDLINE) {
+                        m->creds.cmdline = d->str;
+                        m->creds.cmdline_length = l;
+                        m->creds.mask |= SD_BUS_CREDS_CMDLINE & bus->creds_mask;
+
+                } else if (d->type == KDBUS_MSG_SRC_CGROUP) {
+                        m->creds.cgroup = d->str;
+                        m->creds.mask |= (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID) & bus->creds_mask;
+
+                } else if (d->type == KDBUS_MSG_SRC_AUDIT) {
+                        m->creds.audit_session_id = d->audit.sessionid;
+                        m->creds.audit_login_uid = d->audit.loginuid;
+                        m->creds.mask |= (SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID) & bus->creds_mask;
+
+                } else if (d->type == KDBUS_MSG_SRC_CAPS) {
+                        m->creds.capability = d->data;
+                        m->creds.capability_size = l;
+                        m->creds.mask |= (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS) & bus->creds_mask;
+
                 } else if (d->type == KDBUS_MSG_DST_NAME)
                         destination = d->str;
                 else if (d->type != KDBUS_MSG_FDS &&