sd-bus: update to current kernel version, by splitting off the extended KDBUS_ITEM_PIDS structure from KDBUS_ITEM_CREDS

Also:

- adds support for euid, suid, fsuid, egid, sgid, fsgid fields.

- makes augmentation of creds with data from /proc explicitly
  controllable to give apps better control over this, given that this is
  racy.

- enables augmentation for kdbus connections (previously we only did it
  for dbus1). This is useful since with recent kdbus versions it is
  possible for clients to control the metadata they want to send.

- changes sd_bus_query_sender_privilege() to take the euid of the client
  into consideration, if known

- when we don't have permissions to read augmentation data from /proc,
  don't fail, just don't add the data in

1 files changed, 100 insertions, 22 deletions

diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
index c25a4911f..7db912b64 100644
--- a/src/libsystemd/sd-bus/bus-control.c
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -405,24 +405,65 @@ static int bus_populate_creds_from_items(sd_bus *bus,
 
                 switch (item->type) {
 
+                case KDBUS_ITEM_PIDS:
+
+                        if (mask & SD_BUS_CREDS_PID && item->pids.pid > 0) {
+                                c->pid = (pid_t) item->pids.pid;
+                                c->mask |= SD_BUS_CREDS_PID;
+                        }
+
+                        if (mask & SD_BUS_CREDS_TID && item->pids.tid > 0) {
+                                c->tid = (pid_t) item->pids.tid;
+                                c->mask |= SD_BUS_CREDS_TID;
+                        }
+
+                        if (mask & SD_BUS_CREDS_PID_STARTTIME && item->pids.starttime > 0) {
+                                c->pid_starttime = item->pids.starttime;
+                                c->mask |= SD_BUS_CREDS_PID_STARTTIME;
+                        }
+
+                        break;
+
                 case KDBUS_ITEM_CREDS:
-                        m = (SD_BUS_CREDS_UID | SD_BUS_CREDS_GID | SD_BUS_CREDS_PID) & mask;
 
-                        if (m) {
+                        if (mask & SD_BUS_CREDS_UID && (uid_t) item->creds.uid != (uid_t) -1) {
                                 c->uid = (uid_t) item->creds.uid;
-                                c->pid = (pid_t) item->creds.pid;
+                                c->mask |= SD_BUS_CREDS_UID;
+                        }
+
+                        if (mask & SD_BUS_CREDS_EUID && (uid_t) item->creds.euid != (uid_t) -1) {
+                                c->euid = (uid_t) item->creds.euid;
+                                c->mask |= SD_BUS_CREDS_EUID;
+                        }
+
+                        if (mask & SD_BUS_CREDS_SUID && (uid_t) item->creds.suid != (uid_t) -1) {
+                                c->suid = (uid_t) item->creds.suid;
+                                c->mask |= SD_BUS_CREDS_SUID;
+                        }
+
+                        if (mask & SD_BUS_CREDS_FSUID && (uid_t) item->creds.fsuid != (uid_t) -1) {
+                                c->fsuid = (uid_t) item->creds.fsuid;
+                                c->mask |= SD_BUS_CREDS_FSUID;
+                        }
+
+                        if (mask & SD_BUS_CREDS_GID && (gid_t) item->creds.gid != (gid_t) -1) {
                                 c->gid = (gid_t) item->creds.gid;
-                                c->mask |= m;
+                                c->mask |= SD_BUS_CREDS_GID;
                         }
 
-                        if (mask & SD_BUS_CREDS_TID && item->creds.tid > 0) {
-                                c->tid = (pid_t) item->creds.tid;
-                                c->mask |= SD_BUS_CREDS_TID;
+                        if (mask & SD_BUS_CREDS_EGID && (gid_t) item->creds.egid != (gid_t) -1) {
+                                c->egid = (gid_t) item->creds.egid;
+                                c->mask |= SD_BUS_CREDS_EGID;
                         }
 
-                        if (mask & SD_BUS_CREDS_PID_STARTTIME && item->creds.starttime > 0) {
-                                c->pid_starttime = item->creds.starttime;
-                                c->mask |= SD_BUS_CREDS_PID_STARTTIME;
+                        if (mask & SD_BUS_CREDS_SGID && (gid_t) item->creds.sgid != (gid_t) -1) {
+                                c->sgid = (gid_t) item->creds.sgid;
+                                c->mask |= SD_BUS_CREDS_SGID;
+                        }
+
+                        if (mask & SD_BUS_CREDS_FSGID && (gid_t) item->creds.fsgid != (gid_t) -1) {
+                                c->fsgid = (gid_t) item->creds.fsgid;
+                                c->mask |= SD_BUS_CREDS_FSGID;
                         }
 
                         break;
@@ -581,6 +622,19 @@ static int bus_get_name_creds_kdbus(
         cmd->size = size;
         kdbus_translate_attach_flags(mask, (uint64_t*) &cmd->flags);
 
+        /* If augmentation is on, and the bus doesn't didn't allow us
+         * to get the bits we want, then ask for the PID/TID so that we
+         * can read the rest from /proc. */
+        if ((mask & SD_BUS_CREDS_AUGMENT) &&
+            (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+                     SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
+                     SD_BUS_CREDS_COMM|SD_BUS_CREDS_TID_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
+                     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|
+                     SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS|
+                     SD_BUS_CREDS_SELINUX_CONTEXT|
+                     SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID)))
+                cmd->flags |= KDBUS_ATTACH_PIDS;
+
         r = ioctl(bus->input_fd, KDBUS_CMD_CONN_INFO, cmd);
         if (r < 0)
                 return -errno;
@@ -615,6 +669,10 @@ static int bus_get_name_creds_kdbus(
         if (r < 0)
                 goto fail;
 
+        r = bus_creds_add_more(c, mask, 0, 0);
+        if (r < 0)
+                goto fail;
+
         if (creds) {
                 *creds = c;
                 c = NULL;
@@ -673,11 +731,17 @@ static int bus_get_name_creds_dbus1(
                         c->mask |= SD_BUS_CREDS_UNIQUE_NAME;
                 }
 
-                if (mask & (SD_BUS_CREDS_PID|SD_BUS_CREDS_PID_STARTTIME|SD_BUS_CREDS_GID|
-                            SD_BUS_CREDS_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
-                            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|
-                            SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS|
-                            SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID)) {
+                if ((mask & SD_BUS_CREDS_PID) ||
+                    ((mask & SD_BUS_CREDS_AUGMENT) &&
+                     (mask & (SD_BUS_CREDS_PID_STARTTIME|
+                              SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+                              SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
+                              SD_BUS_CREDS_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
+                              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|
+                              SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS|
+                              SD_BUS_CREDS_SELINUX_CONTEXT|
+                              SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID)))) {
+
                         uint32_t u;
 
                         r = sd_bus_call_method(
@@ -781,7 +845,7 @@ _public_ int sd_bus_get_name_creds(
 
         assert_return(bus, -EINVAL);
         assert_return(name, -EINVAL);
-        assert_return(mask <= _SD_BUS_CREDS_ALL, -ENOTSUP);
+        assert_return((mask & ~SD_BUS_CREDS_AUGMENT) <= _SD_BUS_CREDS_ALL, -ENOTSUP);
         assert_return(mask == 0 || creds, -EINVAL);
         assert_return(!bus_pid_changed(bus), -ECHILD);
         assert_return(service_name_is_valid(name), -EINVAL);
@@ -802,7 +866,7 @@ _public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **r
         int r;
 
         assert_return(bus, -EINVAL);
-        assert_return(mask <= _SD_BUS_CREDS_ALL, -ENOTSUP);
+        assert_return((mask & ~SD_BUS_CREDS_AUGMENT) <= _SD_BUS_CREDS_ALL, -ENOTSUP);
         assert_return(ret, -EINVAL);
         assert_return(!bus_pid_changed(bus), -ECHILD);
 
@@ -837,7 +901,21 @@ _public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **r
                 struct kdbus_info *creator_info;
 
                 cmd.size = sizeof(cmd);
-                cmd.flags = _KDBUS_ATTACH_ALL;
+                kdbus_translate_attach_flags(mask, (uint64_t*) &cmd.flags);
+
+                /* If augmentation is on, and the bus doesn't didn't allow us
+                 * to get the bits we want, then ask for the PID/TID so that we
+                 * can read the rest from /proc. */
+                if ((mask & SD_BUS_CREDS_AUGMENT) &&
+                    (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+                             SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
+                             SD_BUS_CREDS_COMM|SD_BUS_CREDS_TID_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
+                             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|
+                             SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS|
+                             SD_BUS_CREDS_SELINUX_CONTEXT|
+                             SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID)))
+                        cmd.flags |= KDBUS_ATTACH_PIDS;
+
                 r = ioctl(bus->input_fd, KDBUS_CMD_BUS_CREATOR_INFO, &cmd);
                 if (r < 0)
                         return -errno;
@@ -849,12 +927,12 @@ _public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **r
 
                 if (r < 0)
                         return r;
-        } else {
-                r = bus_creds_add_more(c, mask, pid, 0);
-                if (r < 0)
-                        return r;
         }
 
+        r = bus_creds_add_more(c, mask, pid, 0);
+        if (r < 0)
+                return r;
+
         *ret = c;
         c = NULL;
         return 0;