From 05bae4a60c32e29797597979cee2f3684eb3bc1e Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 18 Jan 2015 13:55:55 +0100 Subject: bus: use EUID over UID and fix unix-creds Whenever a process performs an action on an object, the kernel uses the EUID of the process to do permission checks and to apply on any newly created objects. The UID of a process is only used if someone *ELSE* acts on the process. That is, the UID of a process defines who owns the process, the EUID defines what privileges are used by this process when performing an action. Process limits, on the other hand, are always applied to the real UID, not the effective UID. This is, because a process has a user object linked, which always corresponds to its UID. A process never has a user object linked for its EUID. Thus, accounting (and limits) is always done on the real UID. This commit fixes all sd-bus users to use the EUID when performing privilege checks and alike. Furthermore, it fixes unix-creds to be parsed as EUID, not UID (as the kernel always takes the EUID on UDS). Anyone using UID (eg., to do user-accounting) has to fall back to the EUID as UDS does not transmit the UID. --- src/login/logind-session-dbus.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/login/logind-session-dbus.c') diff --git a/src/login/logind-session-dbus.c b/src/login/logind-session-dbus.c index e3486fe5fc..4e7edef52d 100644 --- a/src/login/logind-session-dbus.c +++ b/src/login/logind-session-dbus.c @@ -239,11 +239,11 @@ static int method_set_idle_hint(sd_bus *bus, sd_bus_message *message, void *user if (r < 0) return r; - r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_UID, &creds); + r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_EUID, &creds); if (r < 0) return r; - r = sd_bus_creds_get_uid(creds, &uid); + r = sd_bus_creds_get_euid(creds, &uid); if (r < 0) return r; @@ -302,11 +302,11 @@ static int method_take_control(sd_bus *bus, sd_bus_message *message, void *userd if (r < 0) return r; - r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_UID, &creds); + r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_EUID, &creds); if (r < 0) return r; - r = sd_bus_creds_get_uid(creds, &uid); + r = sd_bus_creds_get_euid(creds, &uid); if (r < 0) return r; -- cgit v1.2.3-54-g00ecf