From 0441b53d55a919b5ac42e997f4092053b017b553 Mon Sep 17 00:00:00 2001 From: Nisha Parrakat Date: Fri, 13 Aug 2021 07:22:02 +0000 Subject: dbus_%.bbappend: stop using selinux_set_mapping https://gitlab.freedesktop.org/dbus/dbus/-/issues/198 https://gitlab.freedesktop.org/dbus/dbus/-/commit/6072f8b24153d844a3033108a17bcd0c1a967816 Currently, if the "dbus" security class or the associated AV doesn't exist, dbus-daemon fails to initialize and exits immediately. Also the security classes or access vector cannot be reordered in the policy. This can be a problem for people developing their own policy or trying to access a machine where, for some reasons, there is not policy defined at all. The code here copy the behaviour of the selinux_check_access() function. We cannot use this function here as it doesn't allow us to define the AVC entry reference. See the discussion at https://marc.info/?l=selinux&m=152163374332372&w=2 Signed-off-by: Nisha Parrakat Signed-off-by: Alexandre Belloni Signed-off-by: Richard Purdie --- meta/recipes-core/dbus/dbus.inc | 1 + .../dbus/dbus/stop_using_selinux_set_mapping.patch | 148 +++++++++++++++++++++ 2 files changed, 149 insertions(+) create mode 100644 meta/recipes-core/dbus/dbus/stop_using_selinux_set_mapping.patch diff --git a/meta/recipes-core/dbus/dbus.inc b/meta/recipes-core/dbus/dbus.inc index f0eeffacc8..adc138bf10 100644 --- a/meta/recipes-core/dbus/dbus.inc +++ b/meta/recipes-core/dbus/dbus.inc @@ -8,6 +8,7 @@ SRC_URI = "https://dbus.freedesktop.org/releases/dbus/dbus-${PV}.tar.gz \ file://tmpdir.patch \ file://dbus-1.init \ file://clear-guid_from_server-if-send_negotiate_unix_f.patch \ + file://stop_using_selinux_set_mapping.patch \ " SRC_URI[md5sum] = "dfe8a71f412e0b53be26ed4fbfdc91c4" diff --git a/meta/recipes-core/dbus/dbus/stop_using_selinux_set_mapping.patch b/meta/recipes-core/dbus/dbus/stop_using_selinux_set_mapping.patch new file mode 100644 index 0000000000..7035098e41 --- /dev/null +++ b/meta/recipes-core/dbus/dbus/stop_using_selinux_set_mapping.patch @@ -0,0 +1,148 @@ +From 6072f8b24153d844a3033108a17bcd0c1a967816 Mon Sep 17 00:00:00 2001 +From: Laurent Bigonville +Date: Sat, 3 Mar 2018 11:15:23 +0100 +Subject: [PATCH] Stop using selinux_set_mapping() function + +Currently, if the "dbus" security class or the associated AV doesn't +exist, dbus-daemon fails to initialize and exits immediately. Also the +security classes or access vector cannot be reordered in the policy. +This can be a problem for people developing their own policy or trying +to access a machine where, for some reasons, there is not policy defined +at all. + +The code here copy the behaviour of the selinux_check_access() function. +We cannot use this function here as it doesn't allow us to define the +AVC entry reference. + +See the discussion at https://marc.info/?l=selinux&m=152163374332372&w=2 + +Resolves: https://gitlab.freedesktop.org/dbus/dbus/issues/198 +--- + bus/selinux.c | 75 ++++++++++++++++++++++++++++----------------------- + 1 file changed, 42 insertions(+), 33 deletions(-) + + +Upstream-Status: Backport +Signed-off-by: Nisha.Parrakat +diff --git a/bus/selinux.c b/bus/selinux.c + +--- a/bus/selinux.c 2021-08-11 14:45:59.048513026 +0000 ++++ b/bus/selinux.c 2021-08-11 14:57:47.144846966 +0000 +@@ -311,24 +311,6 @@ + #endif + } + +-/* +- * Private Flask definitions; the order of these constants must +- * exactly match that of the structure array below! +- */ +-/* security dbus class constants */ +-#define SECCLASS_DBUS 1 +- +-/* dbus's per access vector constants */ +-#define DBUS__ACQUIRE_SVC 1 +-#define DBUS__SEND_MSG 2 +- +-#ifdef HAVE_SELINUX +-static struct security_class_mapping dbus_map[] = { +- { "dbus", { "acquire_svc", "send_msg", NULL } }, +- { NULL } +-}; +-#endif /* HAVE_SELINUX */ +- + /** + * Establish dynamic object class and permission mapping and + * initialize the user space access vector cache (AVC) for D-Bus and set up +@@ -350,13 +332,6 @@ + + _dbus_verbose ("SELinux is enabled in this kernel.\n"); + +- if (selinux_set_mapping (dbus_map) < 0) +- { +- _dbus_warn ("Failed to set up security class mapping (selinux_set_mapping():%s).", +- strerror (errno)); +- return FALSE; +- } +- + avc_entry_ref_init (&aeref); + if (avc_init ("avc", &mem_cb, &log_cb, &thread_cb, &lock_cb) < 0) + { +@@ -421,19 +396,53 @@ + static dbus_bool_t + bus_selinux_check (BusSELinuxID *sender_sid, + BusSELinuxID *override_sid, +- security_class_t target_class, +- access_vector_t requested, ++ const char *target_class, ++ const char *requested, + DBusString *auxdata) + { ++ int saved_errno; ++ security_class_t security_class; ++ access_vector_t requested_access; ++ + if (!selinux_enabled) + return TRUE; + ++ security_class = string_to_security_class (target_class); ++ if (security_class == 0) ++ { ++ saved_errno = errno; ++ log_callback (SELINUX_ERROR, "Unknown class %s", target_class); ++ if (security_deny_unknown () == 0) ++ { ++ return TRUE; ++ } ++ ++ _dbus_verbose ("Unknown class %s\n", target_class); ++ errno = saved_errno; ++ return FALSE; ++ } ++ ++ requested_access = string_to_av_perm (security_class, requested); ++ if (requested_access == 0) ++ { ++ saved_errno = errno; ++ log_callback (SELINUX_ERROR, "Unknown permission %s for class %s", requested, target_class); ++ if (security_deny_unknown () == 0) ++ { ++ return TRUE; ++ } ++ ++ _dbus_verbose ("Unknown permission %s for class %s\n", requested, target_class); ++ errno = saved_errno; ++ return FALSE; ++ } ++ + /* Make the security check. AVC checks enforcing mode here as well. */ + if (avc_has_perm (SELINUX_SID_FROM_BUS (sender_sid), + override_sid ? + SELINUX_SID_FROM_BUS (override_sid) : + bus_sid, +- target_class, requested, &aeref, auxdata) < 0) ++ security_class, requested_access, &aeref, auxdata) < 0) + { + switch (errno) + { +@@ -500,8 +509,8 @@ + + ret = bus_selinux_check (connection_sid, + service_sid, +- SECCLASS_DBUS, +- DBUS__ACQUIRE_SVC, ++ "dbus", ++ "acquire_svc", + &auxdata); + + _dbus_string_free (&auxdata); +@@ -629,8 +638,8 @@ + + ret = bus_selinux_check (sender_sid, + recipient_sid, +- SECCLASS_DBUS, +- DBUS__SEND_MSG, ++ "dbus", ++ "send_msg", + &auxdata); + + _dbus_string_free (&auxdata); -- cgit 1.2.3-korg