exec: introduce PrivateNetwork= process option to turn off network access to specific...

[elogind.git] / src / execute.c

diff --git a/src/execute.c b/src/execute.c
index c69442d0ffeeda1365db6ad07c71e300140c4dd1..c73b0c6c04866704d3af9f750ea5143669daebfa 100644 (file)
--- a/src/execute.c
+++ b/src/execute.c
@@ -56,6 +56,7 @@
 #include "missing.h"
 #include "utmp-wtmp.h"
 #include "def.h"
+#include "loopback-setup.h"
 
 /* This assumes there is a 'tty' group */
 #define TTY_MODE 0620
@@ -549,82 +550,6 @@ static int restore_confirm_stdio(const ExecContext *context,
         return 0;
 }
 
-static int get_group_creds(const char *groupname, gid_t *gid) {
-        struct group *g;
-        unsigned long lu;
-
-        assert(groupname);
-        assert(gid);
-
-        /* We enforce some special rules for gid=0: in order to avoid
-         * NSS lookups for root we hardcode its data. */
-
-        if (streq(groupname, "root") || streq(groupname, "0")) {
-                *gid = 0;
-                return 0;
-        }
-
-        if (safe_atolu(groupname, &lu) >= 0) {
-                errno = 0;
-                g = getgrgid((gid_t) lu);
-        } else {
-                errno = 0;
-                g = getgrnam(groupname);
-        }
-
-        if (!g)
-                return errno != 0 ? -errno : -ESRCH;
-
-        *gid = g->gr_gid;
-        return 0;
-}
-
-static int get_user_creds(const char **username, uid_t *uid, gid_t *gid, const char **home) {
-        struct passwd *p;
-        unsigned long lu;
-
-        assert(username);
-        assert(*username);
-        assert(uid);
-        assert(gid);
-        assert(home);
-
-        /* We enforce some special rules for uid=0: in order to avoid
-         * NSS lookups for root we hardcode its data. */
-
-        if (streq(*username, "root") || streq(*username, "0")) {
-                *username = "root";
-                *uid = 0;
-                *gid = 0;
-                *home = "/root";
-                return 0;
-        }
-
-        if (safe_atolu(*username, &lu) >= 0) {
-                errno = 0;
-                p = getpwuid((uid_t) lu);
-
-                /* If there are multiple users with the same id, make
-                 * sure to leave $USER to the configured value instead
-                 * of the first occurrence in the database. However if
-                 * the uid was configured by a numeric uid, then let's
-                 * pick the real username from /etc/passwd. */
-                if (*username && p)
-                        *username = p->pw_name;
-        } else {
-                errno = 0;
-                p = getpwnam(*username);
-        }
-
-        if (!p)
-                return errno != 0 ? -errno : -ESRCH;
-
-        *uid = p->pw_uid;
-        *gid = p->pw_gid;
-        *home = p->pw_dir;
-        return 0;
-}
-
 static int enforce_groups(const ExecContext *context, const char *username, gid_t gid) {
         bool keep_groups = false;
         int r;
@@ -636,9 +561,12 @@ static int enforce_groups(const ExecContext *context, const char *username, gid_
 
         if (context->group || username) {
 
-                if (context->group)
-                        if ((r = get_group_creds(context->group, &gid)) < 0)
+                if (context->group) {
+                        const char *g = context->group;
+
+                        if ((r = get_group_creds(&g, &gid)) < 0)
                                 return r;
+                }
 
                 /* First step, initialize groups from /etc/groups */
                 if (username && gid != 0) {
@@ -673,13 +601,16 @@ static int enforce_groups(const ExecContext *context, const char *username, gid_
                         k = 0;
 
                 STRV_FOREACH(i, context->supplementary_groups) {
+                        const char *g;
 
                         if (k >= ngroups_max) {
                                 free(gids);
                                 return -E2BIG;
                         }
 
-                        if ((r = get_group_creds(*i, gids+k)) < 0) {
+                        g = *i;
+                        r = get_group_creds(&g, gids+k);
+                        if (r < 0) {
                                 free(gids);
                                 return r;
                         }
@@ -898,6 +829,9 @@ static int setup_pam(
          * might have opened it, but we don't want this fd around. */
         closelog();
 
+        *pam_env = e;
+        e = NULL;
+
         return 0;
 
 fail:
@@ -1063,7 +997,7 @@ int exec_spawn(ExecCommand *command,
 
                 /* This string must fit in 10 chars (i.e. the length
                  * of "/sbin/init") */
-                rename_process("sd.exec");
+                rename_process("sd(EXEC)");
 
                 /* We reset exactly these signals, since they are the
                  * only ones we set to SIG_IGN in the main daemon. All
@@ -1260,7 +1194,7 @@ int exec_spawn(ExecCommand *command,
                 }
 
                 if (apply_permissions)
-                        if (enforce_groups(context, username, uid) < 0) {
+                        if (enforce_groups(context, username, gid) < 0) {
                                 r = EXIT_GROUP;
                                 goto fail_child;
                         }
@@ -1269,12 +1203,20 @@ int exec_spawn(ExecCommand *command,
 
 #ifdef HAVE_PAM
                 if (context->pam_name && username) {
-                        if (setup_pam(context->pam_name, username, context->tty_path, &pam_env, fds, n_fds) < 0) {
+                        if (setup_pam(context->pam_name, username, context->tty_path, &pam_env, fds, n_fds) != 0) {
                                 r = EXIT_PAM;
                                 goto fail_child;
                         }
                 }
 #endif
+                if (context->private_network) {
+                        if (unshare(CLONE_NEWNET) < 0) {
+                                r = EXIT_NETWORK;
+                                goto fail_child;
+                        }
+
+                        loopback_setup();
+                }
 
                 if (strv_length(context->read_write_dirs) > 0 ||
                     strv_length(context->read_only_dirs) > 0 ||
@@ -1469,7 +1411,7 @@ fail_parent:
 void exec_context_init(ExecContext *c) {
         assert(c);
 
-        c->umask = 0002;
+        c->umask = 0022;
         c->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0);
         c->cpu_sched_policy = SCHED_OTHER;
         c->syslog_priority = LOG_DAEMON|LOG_INFO;
@@ -1661,13 +1603,15 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
                 "%sRootDirectory: %s\n"
                 "%sNonBlocking: %s\n"
                 "%sPrivateTmp: %s\n"
-                "%sControlGroupModify: %s\n",
+                "%sControlGroupModify: %s\n"
+                "%sPrivateNetwork: %s\n",
                 prefix, c->umask,
                 prefix, c->working_directory ? c->working_directory : "/",
                 prefix, c->root_directory ? c->root_directory : "/",
                 prefix, yes_no(c->non_blocking),
                 prefix, yes_no(c->private_tmp),
-                prefix, yes_no(c->control_group_modify));
+                prefix, yes_no(c->control_group_modify),
+                prefix, yes_no(c->private_network));
 
         STRV_FOREACH(e, c->environment)
                 fprintf(f, "%sEnvironment: %s\n", prefix, *e);