drop capabilities in lxc-init (V2)

capabilities are reseted just after the filesystem is mounted.
lxc_setup_fs() is moved up, before the process is forked.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/configure.ac b/configure.ac
index 46e8ff768647d8ef103af6eb5bd8e89226a6c3e1..83e01d5e5f3712efb8133ea210b88ce553014265 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -72,6 +72,15 @@ AC_CHECK_HEADERS([linux/netlink.h linux/genetlink.h],
 AC_CHECK_HEADERS([sys/capability.h], [], AC_MSG_ERROR([please install libcap-devel.]),
 [#include <sys/types.h>
 #include <sys/capability.h>])
+AC_CHECK_LIB(cap,cap_set_proc,caplib=yes,caplib=no)
+AC_MSG_CHECKING([linux capabilities])
+if test "x$caplib" = "xyes" ; then
+   CAP_LIBS="-lcap"
+   AC_MSG_RESULT([$CAP_LIBS])
+else
+   AC_MSG_ERROR([not found])
+fi
+AC_SUBST([CAP_LIBS])
 
 # Some systems lack PR_CAPBSET_DROP definition => HAVE_DECL_PR_CAPBSET_DROP
 AC_CHECK_DECLS([PR_CAPBSET_DROP], [], [], [#include <sys/prctl.h>])

diff --git a/src/lxc/Makefile.am b/src/lxc/Makefile.am
index 7c9ae7ad938996c1cfafa9dd75a05fc87aa9670f..41cbb014d57401b312748246d3cd1ac7a42b91ad 100644 (file)
--- a/src/lxc/Makefile.am
+++ b/src/lxc/Makefile.am
@@ -100,6 +100,7 @@ lxc_execute_SOURCES = lxc_execute.c
 lxc_freeze_SOURCES = lxc_freeze.c
 lxc_info_SOURCES = lxc_info.c
 lxc_init_SOURCES = lxc_init.c
+lxc_init_LDADD = $(LDADD) @CAP_LIBS@
 lxc_monitor_SOURCES = lxc_monitor.c
 lxc_restart_SOURCES = lxc_restart.c
 lxc_start_SOURCES = lxc_start.c

diff --git a/src/lxc/lxc_init.c b/src/lxc/lxc_init.c
index a34818e5f13ecbe4952f39fe70ff3a30f3cceb12..270bf35c451364da733eb3e18ac0e7336de2bfd0 100644 (file)
--- a/src/lxc/lxc_init.c
+++ b/src/lxc/lxc_init.c
@@ -30,6 +30,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <sys/capability.h>
 #define _GNU_SOURCE
 #include <getopt.h>
 
@@ -48,6 +49,25 @@ static struct option options[] = {
 
 static int was_interrupted = 0;
 
+static int cap_reset(void)
+{
+       cap_t cap = cap_init();
+       int ret = 0;
+
+       if (!cap) {
+               ERROR("cap_init() failed : %m");
+               return -1;
+       }
+
+       if (cap_set_proc(cap)) {
+               ERROR("cap_set_proc() failed : %m");
+               ret = -1;
+       }
+
+       cap_free(cap);
+       return ret;
+}
+
 int main(int argc, char *argv[])
 {
 
@@ -98,6 +118,12 @@ int main(int argc, char *argv[])
                sigaction(i, &act, NULL);
        }
 
+       if (lxc_setup_fs())
+               exit(err);
+
+       if (cap_reset())
+               exit(err);
+
        pid = fork();
        
        if (pid < 0)
@@ -109,13 +135,10 @@ int main(int argc, char *argv[])
                        signal(i, SIG_DFL);
                sigprocmask(SIG_SETMASK, &omask, NULL);
 
-               if (lxc_setup_fs())
-                       exit(err);
-
                NOTICE("about to exec '%s'", aargv[0]);
 
                execvp(aargv[0], aargv);
-               ERROR("failed to exec: '%s' : %s", aargv[0], strerror(errno));
+               ERROR("failed to exec: '%s' : %m", aargv[0]);
                exit(err);
        }