Add missing exports, set return value

[lttng-ust.git] / libust / lttng-ust-comm.c

diff --git a/libust/lttng-ust-comm.c b/libust/lttng-ust-comm.c
index ee187f8b9308f8d41dd50b9f76611a938506827b..0f7bc34b6ed14200af50f44731c89ca1ee1a4457 100644 (file)
--- a/libust/lttng-ust-comm.c
+++ b/libust/lttng-ust-comm.c
@@ -21,6 +21,7 @@
 
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <sys/prctl.h>
 #include <unistd.h>
 #include <errno.h>
 #include <pthread.h>
@@ -33,6 +34,7 @@
 #include <ust/usterr-signal-safe.h>
 #include <ust/lttng-ust-abi.h>
 #include <ust/tracepoint.h>
+#include <ust/tracepoint-internal.h>
 
 /*
  * Has lttng ust comm constructor been called ?
@@ -73,7 +75,8 @@ struct sock_info {
        int socket;
        pthread_t ust_listener; /* listener thread */
        int root_handle;
-       int constructor_sem_posted;;
+       int constructor_sem_posted;
+       int allowed;
 };
 
 /* Socket from app (connect) to session daemon (listen) for communication */
@@ -82,6 +85,7 @@ struct sock_info global_apps = {
        .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK,
        .socket = -1,
        .root_handle = -1,
+       .allowed = 1,
 };
 
 /* TODO: allow global_apps_sock_path override */
@@ -90,6 +94,7 @@ struct sock_info local_apps = {
        .name = "local",
        .socket = -1,
        .root_handle = -1,
+       .allowed = 0,   /* Check setuid bit first */
 };
 
 extern void ltt_ring_buffer_client_overwrite_init(void);
@@ -100,10 +105,19 @@ extern void ltt_ring_buffer_client_discard_exit(void);
 extern void ltt_ring_buffer_metadata_client_exit(void);
 
 static
-int setup_local_apps_socket(void)
+int setup_local_apps(void)
 {
        const char *home_dir;
 
+       /*
+        * Disallow per-user tracing for setuid binaries.
+        */
+       if (getuid() != geteuid()) {
+               local_apps.allowed = 0;
+               return 0;
+       } else {
+               local_apps.allowed = 1;
+       }
        home_dir = (const char *) getenv("HOME");
        if (!home_dir)
                return -ENOENT;
@@ -116,17 +130,28 @@ static
 int register_app_to_sessiond(int socket)
 {
        ssize_t ret;
+       int prctl_ret;
        struct {
                uint32_t major;
                uint32_t minor;
                pid_t pid;
+               pid_t ppid;
                uid_t uid;
+               gid_t gid;
+               char name[16];  /* process name */
        } reg_msg;
 
        reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR;
        reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR;
        reg_msg.pid = getpid();
+       reg_msg.ppid = getppid();
        reg_msg.uid = getuid();
+       reg_msg.gid = getgid();
+       prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0);
+       if (prctl_ret) {
+               ERR("Error executing prctl");
+               return -errno;
+       }
 
        ret = lttcomm_send_unix_sock(socket, &reg_msg, sizeof(reg_msg));
        if (ret >= 0 && ret != sizeof(reg_msg))
@@ -165,9 +190,7 @@ int handle_register_done(struct sock_info *sock_info)
                return 0;
        sock_info->constructor_sem_posted = 1;
        ret = uatomic_add_return(&sem_count, -1);
-       fprintf(stderr, "DEC ret %d\n", ret);
        if (ret == 0) {
-               fprintf(stderr, "POST\n");
                ret = sem_post(&constructor_wait);
                assert(!ret);
        }
@@ -439,16 +462,20 @@ void __attribute__((constructor)) lttng_ust_init(void)
        ret = sem_init(&constructor_wait, 0, 0);
        assert(!ret);
 
-       ret = setup_local_apps_socket();
+       ret = setup_local_apps();
        if (ret) {
-               ERR("Error setting up to local apps socket");
+               ERR("Error setting up to local apps");
        }
-
-       ret = pthread_create(&global_apps.ust_listener, NULL,
-                       ust_listener_thread, &global_apps);
        ret = pthread_create(&local_apps.ust_listener, NULL,
                        ust_listener_thread, &local_apps);
 
+       if (local_apps.allowed) {
+               ret = pthread_create(&global_apps.ust_listener, NULL,
+                               ust_listener_thread, &global_apps);
+       } else {
+               handle_register_done(&local_apps);
+       }
+
        switch (timeout_mode) {
        case 1: /* timeout wait */
                do {
@@ -491,21 +518,21 @@ void __attribute__((destructor)) lttng_ust_exit(void)
        lttng_ust_comm_should_quit = 1;
        pthread_mutex_unlock(&lttng_ust_comm_mutex);
 
-#if 0
        ret = pthread_cancel(global_apps.ust_listener);
        if (ret) {
                ERR("Error cancelling global ust listener thread");
        }
-#endif //0
 
        cleanup_sock_info(&global_apps);
 
-       ret = pthread_cancel(local_apps.ust_listener);
-       if (ret) {
-               ERR("Error cancelling local ust listener thread");
-       }
+       if (local_apps.allowed) {
+               ret = pthread_cancel(local_apps.ust_listener);
+               if (ret) {
+                       ERR("Error cancelling local ust listener thread");
+               }
 
-       cleanup_sock_info(&local_apps);
+               cleanup_sock_info(&local_apps);
+       }
 
        lttng_ust_abi_exit();
        ltt_events_exit();