Debian bug : https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=760602
** Description changed: [Impact] * xl2tpd crash with segmentation fault when disconnecting from L2TP/IPSec VPN * pppd processes never reaped, user will have to manually intervene to clean up * this will be a major annoyance for our users and I suggest we add this update to the stable release. * the proposed debdiff fixes this problem by patching a NULL-pointer de-reference in the upstream code. [Test Case] * Set up L2TP/IPSec VPN server 1. create a VM on your computer and install Ubuntu Xenial on it (must be VM, IPSec won't work in LXC) 2. sudo apt install xl2tpd libssl-dev 3. get and run this script: https://github.com/philpl/setup-strong-strongswan * Set up L2TP/IPSec VPN client 1. sudo add-apt-repository ppa:nm-l2tp/network-manager-l2tp sudo apt update sudo apt install network-manager-l2tp 2. sudo service xl2tpd stop (https://github.com/nm-l2tp/network-manager-l2tp/issues/38) 3. Configure L2TP/IPSec VPN using Network Manager GUI and point it to the IP of your VM 4. Connect 5. Disconnect 6. Observe that you see xl2tpd SIGSEGV in dmesg and that pppd is still running. [Regression Potential] * The patch contains a check for NULL before de-referencing a pointer during cleanup. The same code has been tested for quite some time in the upstream 1.3.8 release that is available in Z and AA. + + * Patch already in Debian upstream for quite some time as well : + https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=760602 [Original bug description] Ubuntu Xenial xl2tpd[20221]: segfault at 188 ip 000000000040bd08 sp 00007ffd8b6546b0 error 4 in xl2tpd[400000+1b000] Core was generated by `/usr/sbin/xl2tpd -D -c /var/run/nm-xl2tpd.conf.20135 -C /var/run/nm-xl2tpd_l2tp'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x000000000040bd08 in destroy_call (c=0x171d110) at call.c:420 420 call.c: No such file or directory. (gdb) bt #0 0x000000000040bd08 in destroy_call (c=0x171d110) at call.c:420 #1 0x000000000040bf90 in call_close (c=<optimized out>) at call.c:358 #2 0x000000000040c155 in call_close (c=0x171cb40) at call.c:335 #3 0x00000000004023d6 in death_handler (signal=signal@entry=15) at xl2tpd.c:294 #4 0x00000000004024bf in process_signal () at xl2tpd.c:338 #5 0x000000000040d016 in network_thread () at network.c:455 #6 0x0000000000401b96 in main (argc=<optimized out>, argv=<optimized out>) at xl2tpd.c:1557 (gdb) print *c $1 = {lbit = 0, seq_reqd = 0, tx_pkts = 0, rx_pkts = 0, tx_bytes = 0, rx_bytes = 0, zlb_xmit = 0x0, prx = 0, state = 12, frame = 1, next = 0x0, debug = 0, msgtype = -1, ourcid = 106, cid = 10304, qcid = -1, bearer = -1, serno = 1, addr = 0, txspeed = 0, rxspeed = 0, ppd = 0, physchan = -1, dialed = '\000' <repeats 119 times>, dialing = '\000' <repeats 119 times>, subaddy = '\000' <repeats 119 times>, needclose = 0, closing = -1, container = 0x171c6a0, fd = -1, oldptyconf = 0x171d460, die = 0, nego = 0, pppd = 20222, result = -1, error = -1, fbit = 0, ourfbit = 0, cnu = 0, pnu = 0, errormsg = '\000' <repeats 119 times>, lastsent = {tv_sec = 0, tv_usec = 0}, data_seq_num = 0, data_rec_seq_num = 0, closeSs = 0, pLr = -1, lns = 0x0, lac = 0x171d4d0, dial_no = '\000' <repeats 127 times>} (gdb) print c->lns $2 = (struct lns *) 0x0 (gdb) This is a NULL pointer de-reference and is fixed in this commit: https://github.com/xelerance/xl2tpd/commit/a193e02c741168a9b9072b523f2d6faf14a049da ** Bug watch added: Debian Bug tracker #760602 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=760602 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1677990 Title: xl2tpd crash when tearing down L2TP/IPSec VPN connection To manage notifications about this bug go to: https://bugs.launchpad.net/linuxmint/+bug/1677990/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
