Found bug, please accept a patch in upstream

[nevapadonak]

Hello,
The bug is in xl2tpd-control.c, static array commands has no last element filled by NULLs:

struct command_t commands[] = {
    {"add-lac",       &command_add_lac,       TUNNEL_REQUIRED},
    {"connect-lac",   &command_connect_lac,   TUNNEL_REQUIRED},
    {"disconnect-lac",&command_disconnect_lac,TUNNEL_REQUIRED},
    {"status-lac",    &command_status_lac,    TUNNEL_REQUIRED},
    {"remove-lac",    &command_remove_lac,    TUNNEL_REQUIRED},
    {"available",     &command_available,     TUNNEL_NOT_REQUIRED},
    {"add-lns",       &command_add_lns,       TUNNEL_REQUIRED},
    {"status-lns",    &command_status_lns,    TUNNEL_REQUIRED},
    {"remove-lns",    &command_remove_lns,    TUNNEL_REQUIRED},
};

There is the loop in main() going through this array:

    /* parse command name */
    for (command = commands; command->name; command++)
    {
        if (!strcasecmp (argv[i], command->name))
        {
            i++;
            break;
        }
    }

But there is no guarantee that after the last element the memory will be filled by zeroes.
So it may works and may not.
In my environment (ARM, OpenWRT v21.02.0 distro) the program fails with segmentation fault.

This is the fix below. Please add in your code.

--- a/xl2tpd-control.c	2022-08-11 21:39:47.754446499 +0300
+++ b/xl2tpd-control.c	2022-08-11 21:40:16.849022167 +0300
@@ -83,7 +83,9 @@
     {"available",     &command_available,     TUNNEL_NOT_REQUIRED},
     {"add-lns",       &command_add_lns,       TUNNEL_REQUIRED},
     {"status-lns",    &command_status_lns,    TUNNEL_REQUIRED},
-    {"remove-lns",    &command_remove_lns,    TUNNEL_REQUIRED}
+    {"remove-lns",    &command_remove_lns,    TUNNEL_REQUIRED},
+
+    {NULL, NULL, TUNNEL_REQUIRED}
 };
 
 void usage()

[shussain]

PR merged into 1.3.19dev branch