bus-proxy: close each connection fd only once

[elogind.git] / src / bus-proxyd / bus-proxyd.c

diff --git a/src/bus-proxyd/bus-proxyd.c b/src/bus-proxyd/bus-proxyd.c
index 15a79fc427946b7e5b6026792fa53d5aa948431e..478dd78744eb6d6639cbb49f2ebf2d30b44d438d 100644 (file)
--- a/src/bus-proxyd/bus-proxyd.c
+++ b/src/bus-proxyd/bus-proxyd.c
@@ -29,7 +29,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
-#include <sys/poll.h>
+#include <poll.h>
 #include <sys/prctl.h>
 #include <stddef.h>
 #include <getopt.h>
@@ -61,13 +61,15 @@ static char **arg_configuration = NULL;
 
 typedef struct {
         int fd;
+        SharedPolicy *policy;
+        uid_t bus_uid;
 } ClientContext;
 
 static ClientContext *client_context_free(ClientContext *c) {
         if (!c)
                 return NULL;
 
-        close(c->fd);
+        safe_close(c->fd);
         free(c);
 
         return NULL;
@@ -75,14 +77,14 @@ static ClientContext *client_context_free(ClientContext *c) {
 
 DEFINE_TRIVIAL_CLEANUP_FUNC(ClientContext*, client_context_free);
 
-static int client_context_new(ClientContext **out, int fd) {
+static int client_context_new(ClientContext **out) {
         _cleanup_(client_context_freep) ClientContext *c = NULL;
 
         c = new0(ClientContext, 1);
         if (!c)
                 return log_oom();
 
-        c->fd = fd;
+        c->fd = -1;
 
         *out = c;
         c = NULL;
@@ -99,17 +101,19 @@ static void *run_client(void *userdata) {
         if (r < 0)
                 goto exit;
 
+        c->fd = -1;
+
         /* set comm to "p$PIDu$UID" and suffix with '*' if truncated */
         r = snprintf(comm, sizeof(comm), "p" PID_FMT "u" UID_FMT, p->local_creds.pid, p->local_creds.uid);
         if (r >= (ssize_t)sizeof(comm))
                 comm[sizeof(comm) - 2] = '*';
         (void) prctl(PR_SET_NAME, comm);
 
-        r = proxy_load_policy(p, arg_configuration);
+        r = proxy_set_policy(p, c->policy, arg_configuration);
         if (r < 0)
                 goto exit;
 
-        r = proxy_hello_policy(p, getuid());
+        r = proxy_hello_policy(p, c->bus_uid);
         if (r < 0)
                 goto exit;
 
@@ -119,7 +123,8 @@ exit:
         return NULL;
 }
 
-static int loop_clients(int accept_fd) {
+static int loop_clients(int accept_fd, uid_t bus_uid) {
+        _cleanup_(shared_policy_freep) SharedPolicy *sp = NULL;
         pthread_attr_t attr;
         int r;
 
@@ -135,6 +140,10 @@ static int loop_clients(int accept_fd) {
                 goto exit_attr;
         }
 
+        r = shared_policy_new(&sp);
+        if (r < 0)
+                goto exit_attr;
+
         for (;;) {
                 ClientContext *c;
                 pthread_t tid;
@@ -149,13 +158,17 @@ static int loop_clients(int accept_fd) {
                         break;
                 }
 
-                r = client_context_new(&c, fd);
+                r = client_context_new(&c);
                 if (r < 0) {
                         log_oom();
                         close(fd);
                         continue;
                 }
 
+                c->fd = fd;
+                c->policy = sp;
+                c->bus_uid = bus_uid;
+
                 r = pthread_create(&tid, &attr, run_client, c);
                 if (r < 0) {
                         log_error("Cannot spawn thread: %m");
@@ -283,12 +296,31 @@ static int parse_argv(int argc, char *argv[]) {
 }
 
 int main(int argc, char *argv[]) {
+        const char *user = "systemd-bus-proxy";
         int r, accept_fd;
+        uid_t uid, bus_uid;
+        gid_t gid;
 
         log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
         log_parse_environment();
         log_open();
 
+        bus_uid = getuid();
+
+        if (geteuid() == 0) {
+                r = get_user_creds(&user, &uid, &gid, NULL, NULL);
+                if (r < 0) {
+                        log_error_errno(r, "Cannot resolve user name %s: %m", user);
+                        goto finish;
+                }
+
+                r = drop_privileges(uid, gid, 1ULL << CAP_IPC_OWNER);
+                if (r < 0) {
+                        log_error_errno(r, "Cannot drop privileges: %m");
+                        goto finish;
+                }
+        }
+
         r = parse_argv(argc, argv);
         if (r <= 0)
                 goto finish;
@@ -306,7 +338,7 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        r = loop_clients(accept_fd);
+        r = loop_clients(accept_fd, bus_uid);
 
 finish:
         sd_notify(false,