From 7a58bfa4aef88c9ddead6668d83640f762938e72 Mon Sep 17 00:00:00 2001 From: Daniel J Walsh Date: Thu, 22 Jul 2010 17:01:25 -0400 Subject: [PATCH] socket: SELinux support for socket creation. It seems to work on my machine. /proc/1/fd/20 system_u:system_r:system_dbusd_t:s0 /proc/1/fd/21 system_u:system_r:avahi_t:s0 And the AVC's seem to have dissapeared when a confined app trys to connect to dbus or avahi. If you run with this patch and selinux-policy-3.8.8-3.fc14.noarch You should be able to boot in enforcing mode. --- Makefile.am | 3 +- configure.ac | 5 +++ src/socket-util.c | 19 ++++++--- src/socket-util.h | 3 +- src/socket.c | 102 ++++++++++++++++++++++++++++++++++++++-------- 5 files changed, 107 insertions(+), 25 deletions(-) diff --git a/Makefile.am b/Makefile.am index 4dcecc5c..0c3262e0 100644 --- a/Makefile.am +++ b/Makefile.am @@ -298,7 +298,8 @@ libsystemd_core_la_LIBADD = \ $(DBUS_LIBS) \ $(UDEV_LIBS) \ $(LIBWRAP_LIBS) \ - $(PAM_LIBS) + $(PAM_LIBS) \ + $(SELINUX_LIBS) # This is needed because automake is buggy in how it generates the # rules for C programs, but not Vala programs. We therefore can't diff --git a/configure.ac b/configure.ac index 03feb431..14622e47 100644 --- a/configure.ac +++ b/configure.ac @@ -105,6 +105,11 @@ PKG_CHECK_MODULES(DBUS, [ dbus-1 >= 1.3.2 ]) AC_SUBST(DBUS_CFLAGS) AC_SUBST(DBUS_LIBS) +PKG_CHECK_MODULES(SELINUX, [ libselinux ]) +AC_SUBST(SELINUX_CFLAGS) +AC_SUBST(SELINUX_LIBS) +AC_SEARCH_LIBS([is_selinux_enabled], [selinux], [], [AC_MSG_ERROR([*** libselinux library not found])]) + PKG_CHECK_MODULES(DBUSGLIB, [ dbus-glib-1 ]) AC_SUBST(DBUSGLIB_CFLAGS) AC_SUBST(DBUSGLIB_LIBS) diff --git a/src/socket-util.c b/src/socket-util.c index 442abfe1..3a00fcf4 100644 --- a/src/socket-util.c +++ b/src/socket-util.c @@ -29,6 +29,7 @@ #include #include #include +#include #include "macro.h" #include "util.h" @@ -305,7 +306,7 @@ int socket_address_listen( bool free_bind, mode_t directory_mode, mode_t socket_mode, - /* FIXME SELINUX: pass SELinux context object here */ + security_context_t scon, int *ret) { int r, fd, one; @@ -315,11 +316,19 @@ int socket_address_listen( if ((r = socket_address_verify(a)) < 0) return r; - /* FIXME SELINUX: The socket() here should be done with the - * right SELinux context set */ + if (setsockcreatecon(scon) < 0) { + log_error("Failed to set SELinux context (%s) on socket: %m", scon); + if (security_getenforce() == 1) + return -errno; + } + + fd = socket(socket_address_family(a), a->type | SOCK_NONBLOCK | SOCK_CLOEXEC, 0); + r = fd < 0 ? -errno : 0; + + setsockcreatecon(NULL); - if ((fd = socket(socket_address_family(a), a->type | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)) < 0) - return -errno; + if (r < 0) + return r; if (socket_address_family(a) == AF_INET6 && only != SOCKET_ADDRESS_DEFAULT) { int flag = only == SOCKET_ADDRESS_IPV6_ONLY; diff --git a/src/socket-util.h b/src/socket-util.h index 68c579b0..841570f0 100644 --- a/src/socket-util.h +++ b/src/socket-util.h @@ -26,6 +26,7 @@ #include #include #include +#include #include "macro.h" #include "util.h" @@ -71,7 +72,7 @@ int socket_address_listen( bool free_bind, mode_t directory_mode, mode_t socket_mode, - /* FIXME SELINUX: pass SELinux context object here */ + security_context_t scon, int *ret); bool socket_address_is(const SocketAddress *a, const char *s, int type); diff --git a/src/socket.c b/src/socket.c index b06ba093..82a9348d 100644 --- a/src/socket.c +++ b/src/socket.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "unit.h" #include "socket.h" @@ -642,24 +643,89 @@ static void socket_apply_fifo_options(Socket *s, int fd) { log_warning("F_SETPIPE_SZ: %m"); } +static int selinux_getconfromexe( + const char *exe, + security_context_t *newcon) { + + security_context_t mycon = NULL, fcon = NULL; + security_class_t sclass; + int r = 0; + + r = getcon(&mycon); + if (r < 0) + goto fail; + + r = getfilecon(exe, &fcon); + if (r < 0) + goto fail; + + sclass = string_to_security_class("process"); + r = security_compute_create(mycon, fcon, sclass, newcon); + +fail: + if (r < 0) + r = -errno; + + freecon(mycon); + freecon(fcon); + return r; +} + +static int selinux_getfileconfrompath( + const security_context_t scon, + const char *path, + const char *class, + security_context_t *fcon) { + + security_context_t dir_con = NULL; + security_class_t sclass; + int r = 0; + + r = getfilecon(path, &dir_con); + if (r >= 0) { + r = -1; + if ((sclass = string_to_security_class(class)) != 0) + r = security_compute_create(scon, dir_con, sclass, fcon); + } + if (r < 0) + r = -errno; + + freecon(dir_con); + return r; +} + static int fifo_address_create( const char *path, mode_t directory_mode, mode_t socket_mode, - /* FIXME SELINUX: pass SELinux context object here */ + security_context_t scon, int *_fd) { - int fd = -1, r; + int fd = -1, r = 0; struct stat st; mode_t old_mask; + security_context_t filecon = NULL; assert(path); assert(_fd); mkdir_parents(path, directory_mode); - /* FIXME SELINUX: The mkfifo here should be done with - * the right SELinux context set */ + if (scon) { + if (scon && ((r = selinux_getfileconfrompath(scon, path, "fifo_file", &filecon)) == 0)) { + r = setfscreatecon(filecon); + + if (r < 0) { + log_error("Failed to set SELinux file context (%s) on %s: %m", scon, path); + r = -errno; + } + + freecon(filecon); + } + + if (r < 0 && security_getenforce() == 1) + goto fail; + } /* Enforce the right access mode for the fifo */ old_mask = umask(~ socket_mode); @@ -680,6 +746,8 @@ static int fifo_address_create( goto fail; } + setfscreatecon(NULL); + if (fstat(fd, &st) < 0) { r = -errno; goto fail; @@ -698,6 +766,7 @@ static int fifo_address_create( return 0; fail: + setfscreatecon(NULL); if (fd >= 0) close_nointr_nofail(fd); @@ -707,25 +776,20 @@ fail: static int socket_open_fds(Socket *s) { SocketPort *p; int r; + security_context_t scon = NULL; assert(s); - /* FIXME SELINUX: Somewhere here we must set the the SELinux - context for the created sockets and FIFOs. To figure out - the executable name for this, use - socket_instantiate_service() and then access the executable - path name via - s->service->exec_command[SERVICE_EXEC_START]->path. Example: - if ((r = socket_instantiate_service(s)) < 0) return r; - log_debug("Socket unit %s will spawn service unit %s with executable path %s.", - s->meta.id, - s->service->meta.id, - s->service->exec_command[SERVICE_EXEC_START]->path); - */ + if (selinux_getconfromexe(s->service->exec_command[SERVICE_EXEC_START]->path, &scon) < 0) { + log_error("Failed to get SELinux exec context for %s \n", s->service->exec_command[SERVICE_EXEC_START]->path); + if (security_getenforce() == 1) + return -errno; + } + log_debug("SELinux Socket context for %s set to %s\n", s->service->exec_command[SERVICE_EXEC_START]->path, scon); LIST_FOREACH(port, p, s->ports) { if (p->fd >= 0) @@ -741,7 +805,7 @@ static int socket_open_fds(Socket *s) { s->free_bind, s->directory_mode, s->socket_mode, - /* FIXME SELINUX: Pass the SELinux context object here */ + scon, &p->fd)) < 0) goto rollback; @@ -753,7 +817,7 @@ static int socket_open_fds(Socket *s) { p->path, s->directory_mode, s->socket_mode, - /* FIXME SELINUX: Pass the SELinux context object here */ + scon, &p->fd)) < 0) goto rollback; @@ -763,10 +827,12 @@ static int socket_open_fds(Socket *s) { assert_not_reached("Unknown port type"); } + freecon(scon); return 0; rollback: socket_close_fds(s); + freecon(scon); return r; } -- 2.39.5