Fix: sessiond: erroneous user check logic in session_access_ok
[lttng-tools.git] / src / bin / lttng-sessiond / session.c
index 88bbe1309c4a1270cbbf418a97af3d5aeee57fb5..3358648f6864323fbcd2d852bdf1296e7b01cf25 100644 (file)
@@ -1,18 +1,8 @@
 /*
- * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -481,7 +471,7 @@ int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
                                CONSUMER_DST_LOCAL;
 
                session->ust_session->current_trace_chunk = new_trace_chunk;
-                if (is_local_trace) {
+               if (is_local_trace) {
                        enum lttng_error_code ret_error_code;
 
                        ret_error_code = ust_app_create_channel_subdirectories(
@@ -489,7 +479,7 @@ int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
                        if (ret_error_code != LTTNG_OK) {
                                goto error;
                        }
-                }
+               }
                cds_lfht_for_each_entry(
                                session->ust_session->consumer->socks->ht,
                                &iter, socket, node.node) {
@@ -499,11 +489,11 @@ int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
                                        session->id, new_trace_chunk,
                                        DEFAULT_UST_TRACE_DIR);
                        pthread_mutex_unlock(socket->lock);
-                        if (ret) {
+                       if (ret) {
                                goto error;
-                        }
-                }
-        }
+                       }
+               }
+       }
        if (session->kernel_session) {
                const uint64_t relayd_id =
                                session->kernel_session->consumer->net_seq_index;
@@ -520,7 +510,7 @@ int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
                        if (ret_error_code != LTTNG_OK) {
                                goto error;
                        }
-                }
+               }
                cds_lfht_for_each_entry(
                                session->kernel_session->consumer->socks->ht,
                                &iter, socket, node.node) {
@@ -530,11 +520,11 @@ int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
                                        session->id, new_trace_chunk,
                                        DEFAULT_KERNEL_TRACE_DIR);
                        pthread_mutex_unlock(socket->lock);
-                        if (ret) {
+                       if (ret) {
                                goto error;
-                        }
-                }
-        }
+                       }
+               }
+       }
 
        /*
         * Update local current trace chunk state last, only if all remote
@@ -558,7 +548,7 @@ error:
        if (session->kernel_session) {
                session->kernel_session->current_trace_chunk = NULL;
        }
-        /*
+       /*
         * Release references taken in the case where all references could not
         * be acquired.
         */
@@ -802,6 +792,83 @@ end:
        return ret;
 }
 
+/*
+ * This function skips the metadata channel as the begin/end timestamps of a
+ * metadata packet are useless.
+ *
+ * Moreover, opening a packet after a "clear" will cause problems for live
+ * sessions as it will introduce padding that was not part of the first trace
+ * chunk. The relay daemon expects the content of the metadata stream of
+ * successive metadata trace chunks to be strict supersets of one another.
+ *
+ * For example, flushing a packet at the beginning of the metadata stream of
+ * a trace chunk resulting from a "clear" session command will cause the
+ * size of the metadata stream of the new trace chunk to not match the size of
+ * the metadata stream of the original chunk. This will confuse the relay
+ * daemon as the same "offset" in a metadata stream will no longer point
+ * to the same content.
+ */
+static
+enum lttng_error_code session_kernel_open_packets(struct ltt_session *session)
+{
+       enum lttng_error_code ret = LTTNG_OK;
+       struct consumer_socket *socket;
+       struct lttng_ht_iter iter;
+       struct cds_lfht_node *node;
+       struct ltt_kernel_channel *chan;
+
+       rcu_read_lock();
+
+       cds_lfht_first(session->kernel_session->consumer->socks->ht, &iter.iter);
+       node = cds_lfht_iter_get_node(&iter.iter);
+       socket = container_of(node, typeof(*socket), node.node);
+
+       cds_list_for_each_entry(chan,
+                       &session->kernel_session->channel_list.head, list) {
+               int open_ret;
+
+               DBG("Open packet of kernel channel: channel key = %" PRIu64
+                               ", session name = %s, session_id = %" PRIu64,
+                               chan->key, session->name, session->id);
+
+               open_ret = consumer_open_channel_packets(socket, chan->key);
+               if (open_ret < 0) {
+                       /* General error (no known error expected). */
+                       ret = LTTNG_ERR_UNK;
+                       goto end;
+               }
+       }
+
+end:
+       rcu_read_unlock();
+       return ret;
+}
+
+enum lttng_error_code session_open_packets(struct ltt_session *session)
+{
+       enum lttng_error_code ret = LTTNG_OK;
+
+       DBG("Opening packets of session channels: session name = %s, session id = %" PRIu64,
+                       session->name, session->id);
+
+       if (session->ust_session) {
+               ret = ust_app_open_packets(session);
+               if (ret != LTTNG_OK) {
+                       goto end;
+               }
+       }
+
+       if (session->kernel_session) {
+               ret = session_kernel_open_packets(session);
+               if (ret != LTTNG_OK) {
+                       goto end;
+               }
+       }
+
+end:
+       return ret;
+}
+
 /*
  * Set a session's current trace chunk.
  *
@@ -865,7 +932,7 @@ void session_release(struct urcu_ref *ref)
        usess = session->ust_session;
        ksess = session->kernel_session;
 
-        /* Clean kernel session teardown, keeping data for destroy notifier. */
+       /* Clean kernel session teardown, keeping data for destroy notifier. */
        kernel_destroy_session(ksess);
 
        /* UST session teardown, keeping data for destroy notifier. */
@@ -1236,7 +1303,13 @@ int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid)
 {
        assert(session);
 
-       if (uid != session->uid && gid != session->gid && uid != 0) {
+       if (uid == 0) {
+               return 1;
+       }
+
+       return uid == session->uid && gid == session->gid;
+
+       if ((uid != session->uid || gid != session->gid) && uid != 0) {
                return 0;
        } else {
                return 1;
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