selinux: fix potential double free crash in child process

[elogind.git] / src / journal-remote / journal-remote.c

diff --git a/src/journal-remote/journal-remote.c b/src/journal-remote/journal-remote.c
index 1cc86aeaf3bf17a87e7da57357d1a70acf4d3ac2..eb092ce02045439ac267e2227fbfea2dfdd15e76 100644 (file)
--- a/src/journal-remote/journal-remote.c
+++ b/src/journal-remote/journal-remote.c
@@ -222,20 +222,14 @@ static int open_output(Writer *w, const char* host) {
  **********************************************************************/
 
 static int init_writer_hashmap(RemoteServer *s) {
-        static const struct {
-                hash_func_t hash_func;
-                compare_func_t compare_func;
-        } functions[] = {
-                [JOURNAL_WRITE_SPLIT_NONE] = {trivial_hash_func,
-                                              trivial_compare_func},
-                [JOURNAL_WRITE_SPLIT_HOST] = {string_hash_func,
-                                              string_compare_func},
+        static const struct hash_ops *hash_ops[] = {
+                [JOURNAL_WRITE_SPLIT_NONE] = NULL,
+                [JOURNAL_WRITE_SPLIT_HOST] = &string_hash_ops,
         };
 
-        assert(arg_split_mode >= 0 && arg_split_mode < (int) ELEMENTSOF(functions));
+        assert(arg_split_mode >= 0 && arg_split_mode < (int) ELEMENTSOF(hash_ops));
 
-        s->writers = hashmap_new(functions[arg_split_mode].hash_func,
-                                 functions[arg_split_mode].compare_func);
+        s->writers = hashmap_new(hash_ops[arg_split_mode]);
         if (!s->writers)
                 return log_oom();
 
@@ -301,6 +295,8 @@ static int dispatch_raw_source_event(sd_event_source *event,
                                      int fd,
                                      uint32_t revents,
                                      void *userdata);
+static int dispatch_blocking_source_event(sd_event_source *event,
+                                          void *userdata);
 static int dispatch_raw_connection_event(sd_event_source *event,
                                          int fd,
                                          uint32_t revents,
@@ -315,6 +311,8 @@ static int get_source_for_fd(RemoteServer *s,
         Writer *writer;
         int r;
 
+        /* This takes ownership of name, but only on success. */
+
         assert(fd >= 0);
         assert(source);
 
@@ -364,6 +362,8 @@ static int add_source(RemoteServer *s, int fd, char* name, bool own_name) {
         RemoteSource *source;
         int r;
 
+        /* This takes ownership of name, even on failure, if own_name is true. */
+
         assert(s);
         assert(fd >= 0);
         assert(name);
@@ -378,12 +378,20 @@ static int add_source(RemoteServer *s, int fd, char* name, bool own_name) {
         if (r < 0) {
                 log_error("Failed to create source for fd:%d (%s): %s",
                           fd, name, strerror(-r));
+                free(name);
                 return r;
         }
 
         r = sd_event_add_io(s->events, &source->event,
                             fd, EPOLLIN|EPOLLRDHUP|EPOLLPRI,
                             dispatch_raw_source_event, s);
+        if (r == -EPERM) {
+                log_debug("Falling back to sd_event_add_defer for fd:%d (%s)", fd, name);
+                r = sd_event_add_defer(s->events, &source->event,
+                                       dispatch_blocking_source_event, source);
+                if (r == 0)
+                        sd_event_source_set_enabled(source->event, SD_EVENT_ON);
+        }
         if (r < 0) {
                 log_error("Failed to register event source for fd:%d: %s",
                           fd, strerror(-r));
@@ -695,7 +703,7 @@ static int setup_microhttpd_server(RemoteServer *s,
                 goto error;
         }
 
-        r = hashmap_ensure_allocated(&s->daemons, uint64_hash_func, uint64_compare_func);
+        r = hashmap_ensure_allocated(&s->daemons, &uint64_hash_ops);
         if (r < 0) {
                 log_oom();
                 goto error;
@@ -814,13 +822,21 @@ static int remoteserver_init(RemoteServer *s,
                 return -EINVAL;
         }
 
-        sd_event_default(&s->events);
+        r = sd_event_default(&s->events);
+        if (r < 0) {
+                log_error("Failed to allocate event loop: %s", strerror(-r));
+                return r;
+        }
 
         setup_signals(s);
 
         assert(server == NULL);
         server = s;
 
+        r = init_writer_hashmap(s);
+        if (r < 0)
+                return r;
+
         n = sd_listen_fds(true);
         if (n < 0) {
                 log_error("Failed to read listening file descriptors from environment: %s",
@@ -856,8 +872,6 @@ static int remoteserver_init(RemoteServer *s,
                         log_info("Received a connection socket (fd:%d) from %s", fd, hostname);
 
                         r = add_source(s, fd, hostname, true);
-                        if (r < 0)
-                                free(hostname);
                 } else {
                         log_error("Unknown socket passed on fd:%d", fd);
 
@@ -944,10 +958,6 @@ static int remoteserver_init(RemoteServer *s,
                 return -EINVAL;
         }
 
-        r = init_writer_hashmap(s);
-        if (r < 0)
-                return r;
-
         if (arg_split_mode == JOURNAL_WRITE_SPLIT_NONE) {
                 /* In this case we know what the writer will be
                    called, so we can create it and verify that we can
@@ -1031,6 +1041,13 @@ static int dispatch_raw_source_event(sd_event_source *event,
                 return 1;
 }
 
+static int dispatch_blocking_source_event(sd_event_source *event,
+                                          void *userdata) {
+        RemoteSource *source = userdata;
+
+        return dispatch_raw_source_event(event, source->fd, EPOLLIN, server);
+}
+
 static int accept_connection(const char* type, int fd,
                              SocketAddress *addr, char **hostname) {
         int fd2, r;
@@ -1084,7 +1101,7 @@ static int dispatch_raw_connection_event(sd_event_source *event,
                                          uint32_t revents,
                                          void *userdata) {
         RemoteServer *s = userdata;
-        int fd2, r;
+        int fd2;
         SocketAddress addr = {
                 .size = sizeof(union sockaddr_union),
                 .type = SOCK_STREAM,
@@ -1095,10 +1112,7 @@ static int dispatch_raw_connection_event(sd_event_source *event,
         if (fd2 < 0)
                 return fd2;
 
-        r = add_source(s, fd2, hostname, true);
-        if (r < 0)
-                free(hostname);
-        return r;
+        return add_source(s, fd2, hostname, true);
 }
 
 /**********************************************************************