[lttng-dev] [PATCH lttng-tools 05/24] Fix: illegal memory access in enable_event

[Mathieu Desnoyers]

Found by Coverity:
CID 1243033 (#1 of 1): Buffer not null terminated
(BUFFER_SIZE_WARNING)16. buffer_size_warning: Calling strncpy with a
maximum size argument of 256 bytes on destination array msg.name of size
256 bytes might leave the destination string unterminated.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
---
 src/bin/lttng-sessiond/agent.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/bin/lttng-sessiond/agent.c b/src/bin/lttng-sessiond/agent.c
index ced0f85..f79ac00 100644
--- a/src/bin/lttng-sessiond/agent.c
+++ b/src/bin/lttng-sessiond/agent.c
@@ -408,17 +408,20 @@ static int enable_event(struct agent_app *app, struct agent_event *event)
 	}
 	data_size = sizeof(msg) + filter_expression_length;
 
-	ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
-	if (ret < 0) {
-		goto error_io;
-	}
-
 	memset(&msg, 0, sizeof(msg));
 	msg.loglevel_value = htobe32(event->loglevel_value);
 	msg.loglevel_type = htobe32(event->loglevel_type);
-	strncpy(msg.name, event->name, sizeof(msg.name));
+	if (lttng_strncpy(msg.name, event->name, sizeof(msg.name))) {
+		ret = LTTNG_ERR_INVALID;
+		goto error;
+	}
 	msg.filter_expression_length = htobe32(filter_expression_length);
 
+	ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
+	if (ret < 0) {
+		goto error_io;
+	}
+
 	bytes_to_send = zmalloc(data_size);
 	if (!bytes_to_send) {
 		ret = LTTNG_ERR_NOMEM;
-- 
2.1.4