Ulogd / JSON mod -> Segmentation fault

For Developers
1

Hello All,

I have an issue with the trio NFT / ulogd and Json output.

NFT and ulogd are working well with the LOGEMU output but I got an segmentation fault with Json.
I tried may older version of ulogd + mod-Json even the one that working well with OpenWrt 19.07 ( but with iptables)

Some data :

 ulogd.c:1645 initialization finished, entering main loop
Segmentation fault

Error seems to be when a packet is logged by NFT, permission on destination file is OK (set 777 for the test )

ubus call system board
{
        "kernel": "5.15.134",
        "hostname": "OpenWrt",
        "system": "MediaTek MT7621 ver:1 eco:3",
        "model": "Xiaomi Mi Router 3G",
        "board_name": "xiaomi,mi-router-3g",
        "rootfs_type": "squashfs",
        "release": {
                "distribution": "OpenWrt",
                "version": "23.05.0",
                "revision": "r23497-6637af95aa",
                "target": "ramips/mt7621",
                "description": "OpenWrt 23.05.0 r23497-6637af95aa"
        }
}

Logread :


Mon Nov 20 22:38:01 2023 kern.info kernel: [16165.084527] do_page_fault(): sending SIGSEGV to ulogd for invalid write access to 37377834
Mon Nov 20 22:38:01 2023 kern.info kernel: [16165.092806] epc = 00403f8d in ulogd[400000+6000]
Mon Nov 20 22:38:01 2023 kern.info kernel: [16165.097620] ra  = 77c540ad in libjansson.so.4.14.0[77c4d000+1f000]

pkg list-installed | grep ulog
ulogd - 2.0.8-1
ulogd-mod-extra - 2.0.8-1
ulogd-mod-json - 2.0.8-1
ulogd-mod-nfacct - 2.0.8-1
ulogd-mod-nflog - 2.0.8-1

Do you have any idea ?

Thanks.

2

As an information, With the same config files, eveything is working with :slight_smile:

ubus call system board
{
        "kernel": "5.10.176",
        "hostname": "OpenWrt",
        "system": "MediaTek MT7621 ver:1 eco:3",
        "model": "Xiaomi Mi Router 3G",
        "board_name": "xiaomi,mi-router-3g",
        "rootfs_type": "squashfs",
        "release": {
                "distribution": "OpenWrt",
                "version": "22.03.5",
                "revision": "r20134-5f15225c1e",
                "target": "ramips/mt7621",
                "description": "OpenWrt 22.03.5 r20134-5f15225c1e"
        }
}

Ulog version is the same, only the NFT is different downgrade from 1.0.8 to 1.0.2;