server: session: fix memory violation

Fix a bug in which calling the 'stop' command on a session already
closed would crash the C&C server.

Signed-off-by: Danny Holman <dholman@gymli.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/server/src/session.c b/server/src/session.c
index 3dcdfa6..66315fd 100644
--- a/server/src/session.c
+++ b/server/src/session.c
@@ -46,6 +46,9 @@ ssize_t read_session(int id, char *buffer, size_t sz) {
 
 void kill_session(int id) {
         struct session *s = find_session(id);
+        if (s == NULL)
+                return;
+
         s->alive = 0;
         list_del(&s->list);
         close(s->socket);