From 05bae4a60c32e29797597979cee2f3684eb3bc1e Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sun, 18 Jan 2015 13:55:55 +0100 Subject: [PATCH] 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/bus-proxyd/driver.c | 2 +- src/bus-proxyd/proxy.c | 20 ++++++++++---------- src/bus-proxyd/stdio-bridge.c | 4 ++-- src/core/selinux-access.c | 6 +++--- src/libsystemd/sd-bus/bus-control.c | 16 ++++++++-------- src/libsystemd/sd-bus/bus-message.c | 12 ++++++------ src/libsystemd/sd-bus/busctl.c | 4 ++-- src/login/logind-dbus.c | 12 ++++++------ src/login/logind-session-dbus.c | 8 ++++---- 9 files changed, 42 insertions(+), 42 deletions(-) diff --git a/src/bus-proxyd/driver.c b/src/bus-proxyd/driver.c index 361b14c13..b2a44563c 100644 --- a/src/bus-proxyd/driver.c +++ b/src/bus-proxyd/driver.c @@ -252,7 +252,7 @@ int bus_proxy_process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, SharedPoli if (!sd_bus_message_has_signature(m, "s")) return synthetic_reply_method_error(m, &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_INVALID_ARGS, "Invalid parameters")); - r = get_creds_by_message(a, m, SD_BUS_CREDS_UID, &creds, &error); + r = get_creds_by_message(a, m, SD_BUS_CREDS_EUID, &creds, &error); if (r < 0) return synthetic_reply_method_errno(m, r, &error); diff --git a/src/bus-proxyd/proxy.c b/src/bus-proxyd/proxy.c index 329188ecf..bd02ee12b 100644 --- a/src/bus-proxyd/proxy.c +++ b/src/bus-proxyd/proxy.c @@ -73,7 +73,7 @@ static int proxy_create_dest(Proxy *p, const char *dest, const char *local_sec, if (r < 0) return log_error_errno(r, "Failed to set FD negotiation: %m"); - r = sd_bus_negotiate_creds(b, true, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|SD_BUS_CREDS_SELINUX_CONTEXT); + r = sd_bus_negotiate_creds(b, true, SD_BUS_CREDS_EUID|SD_BUS_CREDS_PID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SELINUX_CONTEXT); if (r < 0) return log_error_errno(r, "Failed to set credential negotiation: %m"); @@ -134,7 +134,7 @@ static int proxy_create_local(Proxy *p, int in_fd, int out_fd, bool negotiate_fd if (r < 0) return log_error_errno(r, "Failed to set FD negotiation: %m"); - r = sd_bus_negotiate_creds(b, true, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|SD_BUS_CREDS_SELINUX_CONTEXT); + r = sd_bus_negotiate_creds(b, true, SD_BUS_CREDS_EUID|SD_BUS_CREDS_PID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SELINUX_CONTEXT); if (r < 0) return log_error_errno(r, "Failed to set credential negotiation: %m"); @@ -433,8 +433,8 @@ static int process_policy_unlocked(sd_bus *from, sd_bus *to, sd_bus_message *m, /* The message came from the kernel, and is sent to our legacy client. */ sd_bus_creds_get_well_known_names(&m->creds, &sender_names); - (void) sd_bus_creds_get_uid(&m->creds, &sender_uid); - (void) sd_bus_creds_get_gid(&m->creds, &sender_gid); + (void) sd_bus_creds_get_euid(&m->creds, &sender_uid); + (void) sd_bus_creds_get_egid(&m->creds, &sender_gid); if (sender_uid == UID_INVALID || sender_gid == GID_INVALID) { _cleanup_bus_creds_unref_ sd_bus_creds *sender_creds = NULL; @@ -446,12 +446,12 @@ static int process_policy_unlocked(sd_bus *from, sd_bus *to, sd_bus_message *m, * case, query the creds of the peer * instead. */ - r = bus_get_name_creds_kdbus(from, m->sender, SD_BUS_CREDS_UID|SD_BUS_CREDS_GID, true, &sender_creds); + r = bus_get_name_creds_kdbus(from, m->sender, SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID, true, &sender_creds); if (r < 0) return handle_policy_error(m, r); - (void) sd_bus_creds_get_uid(sender_creds, &sender_uid); - (void) sd_bus_creds_get_gid(sender_creds, &sender_gid); + (void) sd_bus_creds_get_euid(sender_creds, &sender_uid); + (void) sd_bus_creds_get_egid(sender_creds, &sender_gid); } /* First check whether the sender can send the message to our name */ @@ -483,7 +483,7 @@ static int process_policy_unlocked(sd_bus *from, sd_bus *to, sd_bus_message *m, if (m->destination) { r = bus_get_name_creds_kdbus(to, m->destination, SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_UNIQUE_NAME| - SD_BUS_CREDS_UID|SD_BUS_CREDS_GID|SD_BUS_CREDS_PID, + SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_PID, true, &destination_creds); if (r < 0) return handle_policy_error(m, r); @@ -494,8 +494,8 @@ static int process_policy_unlocked(sd_bus *from, sd_bus *to, sd_bus_message *m, sd_bus_creds_get_well_known_names(destination_creds, &destination_names); - (void) sd_bus_creds_get_uid(destination_creds, &destination_uid); - (void) sd_bus_creds_get_gid(destination_creds, &destination_gid); + (void) sd_bus_creds_get_euid(destination_creds, &destination_uid); + (void) sd_bus_creds_get_egid(destination_creds, &destination_gid); } /* First check if we (the sender) can send to this name */ diff --git a/src/bus-proxyd/stdio-bridge.c b/src/bus-proxyd/stdio-bridge.c index c17047b7e..6fb83033d 100644 --- a/src/bus-proxyd/stdio-bridge.c +++ b/src/bus-proxyd/stdio-bridge.c @@ -174,11 +174,11 @@ static int rename_service(sd_bus *a, sd_bus *b) { assert(a); assert(b); - r = sd_bus_get_owner_creds(b, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_COMM|SD_BUS_CREDS_AUGMENT, &creds); + r = sd_bus_get_owner_creds(b, SD_BUS_CREDS_EUID|SD_BUS_CREDS_PID|SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_COMM|SD_BUS_CREDS_AUGMENT, &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; diff --git a/src/core/selinux-access.c b/src/core/selinux-access.c index b45a4513e..f6389584f 100644 --- a/src/core/selinux-access.c +++ b/src/core/selinux-access.c @@ -70,9 +70,9 @@ static int audit_callback( if (sd_bus_creds_get_audit_login_uid(audit->creds, &login_uid) >= 0) snprintf(login_uid_buf, sizeof(login_uid_buf), UID_FMT, login_uid); - if (sd_bus_creds_get_uid(audit->creds, &uid) >= 0) + if (sd_bus_creds_get_euid(audit->creds, &uid) >= 0) snprintf(uid_buf, sizeof(uid_buf), UID_FMT, uid); - if (sd_bus_creds_get_gid(audit->creds, &gid) >= 0) + if (sd_bus_creds_get_egid(audit->creds, &gid) >= 0) snprintf(gid_buf, sizeof(gid_buf), GID_FMT, gid); snprintf(msgbuf, msgbufsize, @@ -203,7 +203,7 @@ int mac_selinux_generic_access_check( r = sd_bus_query_sender_creds( message, - SD_BUS_CREDS_PID|SD_BUS_CREDS_UID|SD_BUS_CREDS_GID| + SD_BUS_CREDS_PID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID| SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_AUDIT_LOGIN_UID| SD_BUS_CREDS_SELINUX_CONTEXT| SD_BUS_CREDS_AUGMENT /* get more bits from /proc */, diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c index b45014078..35c79cf89 100644 --- a/src/libsystemd/sd-bus/bus-control.c +++ b/src/libsystemd/sd-bus/bus-control.c @@ -762,7 +762,7 @@ static int bus_get_name_creds_dbus1( if ((mask & SD_BUS_CREDS_PID) || ((mask & SD_BUS_CREDS_AUGMENT) && - (mask & (SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID| + (mask & (SD_BUS_CREDS_UID|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| @@ -798,7 +798,7 @@ static int bus_get_name_creds_dbus1( reply = sd_bus_message_unref(reply); } - if (mask & SD_BUS_CREDS_UID) { + if (mask & SD_BUS_CREDS_EUID) { uint32_t u; r = sd_bus_call_method( @@ -818,8 +818,8 @@ static int bus_get_name_creds_dbus1( if (r < 0) return r; - c->uid = u; - c->mask |= SD_BUS_CREDS_UID; + c->euid = u; + c->mask |= SD_BUS_CREDS_EUID; reply = sd_bus_message_unref(reply); } @@ -961,13 +961,13 @@ static int bus_get_owner_creds_dbus1(sd_bus *bus, uint64_t mask, sd_bus_creds ** } if (bus->ucred.uid != UID_INVALID) { - c->uid = bus->ucred.uid; - c->mask |= SD_BUS_CREDS_UID & mask; + c->euid = bus->ucred.uid; + c->mask |= SD_BUS_CREDS_EUID & mask; } if (bus->ucred.gid != GID_INVALID) { - c->gid = bus->ucred.gid; - c->mask |= SD_BUS_CREDS_GID & mask; + c->egid = bus->ucred.gid; + c->mask |= SD_BUS_CREDS_EGID & mask; } } diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c index f352c7298..23076d25d 100644 --- a/src/libsystemd/sd-bus/bus-message.c +++ b/src/libsystemd/sd-bus/bus-message.c @@ -424,19 +424,19 @@ int bus_message_from_header( if (ucred) { m->creds.pid = ucred->pid; - m->creds.uid = ucred->uid; - m->creds.gid = ucred->gid; + m->creds.euid = ucred->uid; + m->creds.egid = ucred->gid; /* Due to namespace translations some data might be * missing from this ucred record. */ if (m->creds.pid > 0) m->creds.mask |= SD_BUS_CREDS_PID; - if (m->creds.uid != UID_INVALID) - m->creds.mask |= SD_BUS_CREDS_UID; + if (m->creds.euid != UID_INVALID) + m->creds.mask |= SD_BUS_CREDS_EUID; - if (m->creds.gid != GID_INVALID) - m->creds.mask |= SD_BUS_CREDS_GID; + if (m->creds.egid != GID_INVALID) + m->creds.mask |= SD_BUS_CREDS_EGID; } if (label) { diff --git a/src/libsystemd/sd-bus/busctl.c b/src/libsystemd/sd-bus/busctl.c index c0d51e06a..f0bc2a76a 100644 --- a/src/libsystemd/sd-bus/busctl.c +++ b/src/libsystemd/sd-bus/busctl.c @@ -160,7 +160,7 @@ static int list_bus_names(sd_bus *bus, char **argv) { r = sd_bus_get_name_creds( bus, *i, (arg_augment_creds ? SD_BUS_CREDS_AUGMENT : 0) | - SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_COMM| + SD_BUS_CREDS_EUID|SD_BUS_CREDS_PID|SD_BUS_CREDS_COMM| SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_SESSION| SD_BUS_CREDS_DESCRIPTION, &creds); if (r >= 0) { @@ -178,7 +178,7 @@ static int list_bus_names(sd_bus *bus, char **argv) { } else fputs(" - - ", stdout); - r = sd_bus_creds_get_uid(creds, &uid); + r = sd_bus_creds_get_euid(creds, &uid); if (r >= 0) { _cleanup_free_ char *u = NULL; diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c index bc985a375..f2f91d5de 100644 --- a/src/login/logind-dbus.c +++ b/src/login/logind-dbus.c @@ -1606,11 +1606,11 @@ static int method_do_shutdown_or_sleep( return sd_bus_error_setf(error, BUS_ERROR_SLEEP_VERB_NOT_SUPPORTED, "Sleep verb not supported"); } - 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; @@ -1759,11 +1759,11 @@ static int method_can_shutdown_or_sleep( return sd_bus_reply_method_return(message, "s", "na"); } - 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; @@ -1938,11 +1938,11 @@ static int method_inhibit(sd_bus *bus, sd_bus_message *message, void *userdata, if (r == 0) return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */ - r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID, &creds); + r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_EUID|SD_BUS_CREDS_PID, &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; diff --git a/src/login/logind-session-dbus.c b/src/login/logind-session-dbus.c index e3486fe5f..4e7edef52 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; -- 2.30.2