Error in server mode

[dcapeletti]

After using a tuntox client connected to port 22 of the tuntox server for several minutes, the following error occurs on the server

Created a new tunnel object connid=61202 sockfd=11
2018-01-29 12:21:23: [WARNING]	conn closed!
2018-01-29 12:21:23: [INFO]	Deleting tunnel #61202 ptr 0x1b2f060
2018-01-29 12:21:23: [INFO]	Deleting tunnel #0 ptr 0x1b2f060
*** Error in `/home/username/.tuntox/./tuntox-x64': double free or corruption (fasttop): 0x0000000001b2f060 ***
======= Backtrace: =========
[0x476581]
[0x47eac6]
[0x482af7]
[0x403f76]
[0x406d37]
[0x40822b]
[0x4568b6]
[0x456aaa]
[0x400929]
======= Memory map: ========
00400000-0054c000 r-xp 00000000 08:06 23082910                           /home/username/.tuntox/tuntox-x64
0074b000-00750000 rw-p 0014b000 08:06 23082910                           /home/username/.tuntox/tuntox-x64
00750000-00757000 rw-p 00000000 00:00 0 
01adc000-01b4f000 rw-p 00000000 00:00 0                                  [heap]
7f383c000000-7f383c025000 rw-p 00000000 00:00 0 
7f383c025000-7f3840000000 ---p 00000000 00:00 0 
7f38412c6000-7f38419f1000 rw-p 00000000 00:00 0 
7ffe65745000-7ffe6576a000 rw-p 00000000 00:00 0                          [stack]
7ffe657e2000-7ffe657e4000 r--p 00000000 00:00 0                          [vvar]
7ffe657e4000-7ffe657e6000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]
./Enlace hacia Soporte remoto: línea 3: 11095 Violación de segmento  /home/username/.tuntox/./tuntox-x64 -C /home/username/.tuntox/ -s "soporte123456789"

There is no error in the client mode.

[dcapeletti]

2018-01-29 14:59:47: [WARNING]	conn closed!
2018-01-29 14:59:47: [INFO]	Deleting tunnel #14286 ptr 0xa74280
2018-01-29 14:59:47: [INFO]	Deleting tunnel #35707 ptr 0xabe320
2018-01-29 14:59:47: [INFO]	Deleting tunnel #63009 ptr 0xab7660
2018-01-29 14:59:47: [INFO]	Deleting tunnel #0 ptr 0xab7660
./Enlace hacia Soporte remoto: línea 3: 22800 Violación de segmento /home/username/.tuntox/./tuntox-x64 -C /home/username/.tuntox/ -s "soporte123456789"

This is another error, the server closes but without detail.

[gjedeer]

Thanks! Any sure way to reproduce maybe? Also do you know how to build from source and/or use gdb?

…

On January 29, 2018 7:08:49 PM GMT+01:00, Diego Ariel Capeletti ***@***.***> wrote: ``` 2018-01-29 14:59:47: [WARNING] conn closed! 2018-01-29 14:59:47: [INFO] Deleting tunnel #14286 ptr 0xa74280 2018-01-29 14:59:47: [INFO] Deleting tunnel #35707 ptr 0xabe320 2018-01-29 14:59:47: [INFO] Deleting tunnel #63009 ptr 0xab7660 2018-01-29 14:59:47: [INFO] Deleting tunnel #0 ptr 0xab7660 ./Enlace hacia Soporte remoto: línea 3: 22800 Violación de segmento /home/username/.tuntox/./tuntox-x64 -C /home/username/.tuntox/ -s "soporte123456789" ``` This is another error, the server closes but without detail. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: #50 (comment)

-- Sent from my Android device with K-9 Mail. Please excuse my brevity.

[dcapeletti]

I'm pretty sure I know how to reproduce it.
I will try to build it following this file https://github.com/gjedeer/tuntox/blob/master/BUILD.md
Thanks!

[gjedeer]

Awesome. Here's how to generate a nice backtrace for me: https://wiki.ubuntu.com/Backtrace#Generation

…

On January 29, 2018 7:23:21 PM GMT+01:00, Diego Ariel Capeletti ***@***.***> wrote: I'm pretty sure I know how to reproduce it. I will try to build it following this file https://github.com/gjedeer/tuntox/blob/master/BUILD.md Thanks! -- You are receiving this because you commented. Reply to this email directly or view it on GitHub: #50 (comment)

-- Sent from my Android device with K-9 Mail. Please excuse my brevity.

[dcapeletti]

If you give me a hand, I can move on.
I have already compiled and installed c-toxcore successfully, but I have the following problem when building tuntox. I'm in debian 9.3

$ make
  GEN   gitversion.h
Package libevent_pthreads was not found in the pkg-config search path.
Perhaps you should add the directory containing `libevent_pthreads.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libevent_pthreads' found
  CC    log.o
Package libevent_pthreads was not found in the pkg-config search path.
Perhaps you should add the directory containing `libevent_pthreads.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libevent_pthreads' found
  CC    client.o
Package libevent_pthreads was not found in the pkg-config search path.
Perhaps you should add the directory containing `libevent_pthreads.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libevent_pthreads' found
  CC    gitversion.o
Package libevent_pthreads was not found in the pkg-config search path.
Perhaps you should add the directory containing `libevent_pthreads.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libevent_pthreads' found
  CC    mach.o
Package libevent_pthreads was not found in the pkg-config search path.
Perhaps you should add the directory containing `libevent_pthreads.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libevent_pthreads' found
  CC    main.o
Package libevent_pthreads was not found in the pkg-config search path.
Perhaps you should add the directory containing `libevent_pthreads.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libevent_pthreads' found
  CC    util.o
Package libevent_pthreads was not found in the pkg-config search path.
Perhaps you should add the directory containing `libevent_pthreads.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libevent_pthreads' found
gcc -o tuntox log.o client.o gitversion.o mach.o main.o util.o -lpthread -g -pthread -lm -static -lrt  
main.o: En la función `do_daemonize':
/home/dcapeletti/tuntox/main.c:1091: aviso: Using 'getpwnam' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
client.o: En la función `local_bind':
/home/dcapeletti/tuntox/client.c:61: aviso: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
client.o: En la función `do_client_loop':
/home/dcapeletti/tuntox/client.c:273: referencia a `tox_callback_friend_lossless_packet' sin definir
/home/dcapeletti/tuntox/client.c:292: referencia a `tox_iterate' sin definir
/home/dcapeletti/tuntox/client.c:328: referencia a `tox_friend_add' sin definir
/home/dcapeletti/tuntox/client.c:353: referencia a `tox_friend_get_connection_status' sin definir
/home/dcapeletti/tuntox/client.c:373: referencia a `tox_friend_delete' sin definir
/home/dcapeletti/tuntox/client.c:412: referencia a `tox_friend_send_lossless_packet' sin definir
/home/dcapeletti/tuntox/client.c:580: referencia a `tox_iteration_interval' sin definir
main.o: En la función `do_bootstrap':
/home/dcapeletti/tuntox/main.c:188: referencia a `tox_bootstrap' sin definir
/home/dcapeletti/tuntox/main.c:189: referencia a `tox_add_tcp_relay' sin definir
main.o: En la función `set_tox_username':
/home/dcapeletti/tuntox/main.c:204: referencia a `tox_self_set_name' sin definir
main.o: En la función `send_frame':
/home/dcapeletti/tuntox/main.c:319: referencia a `tox_friend_send_lossless_packet' sin definir
/home/dcapeletti/tuntox/main.c:354: referencia a `tox_iterate' sin definir
main.o: En la función `write_save':
/home/dcapeletti/tuntox/main.c:705: referencia a `tox_get_savedata_size' sin definir
/home/dcapeletti/tuntox/main.c:707: referencia a `tox_get_savedata' sin definir
main.o: En la función `accept_friend_request':
/home/dcapeletti/tuntox/main.c:883: referencia a `tox_friend_add_norequest' sin definir
main.o: En la función `cleanup':
/home/dcapeletti/tuntox/main.c:906: referencia a `tox_kill' sin definir
main.o: En la función `do_server_loop':
/home/dcapeletti/tuntox/main.c:926: referencia a `tox_callback_friend_lossless_packet' sin definir
/home/dcapeletti/tuntox/main.c:941: referencia a `tox_iterate' sin definir
/home/dcapeletti/tuntox/main.c:944: referencia a `tox_iteration_interval' sin definir
main.o: En la función `main':
/home/dcapeletti/tuntox/main.c:1448: referencia a `tox_options_default' sin definir
/home/dcapeletti/tuntox/main.c:1477: referencia a `tox_new' sin definir
/home/dcapeletti/tuntox/main.c:1481: referencia a `tox_new' sin definir
/home/dcapeletti/tuntox/main.c:1484: referencia a `tox_new' sin definir
/home/dcapeletti/tuntox/main.c:1487: referencia a `tox_new' sin definir
/home/dcapeletti/tuntox/main.c:1502: referencia a `tox_callback_self_connection_status' sin definir
/home/dcapeletti/tuntox/main.c:1508: referencia a `tox_self_get_address' sin definir
/home/dcapeletti/tuntox/main.c:1529: referencia a `tox_self_get_address' sin definir
/home/dcapeletti/tuntox/main.c:1535: referencia a `tox_callback_friend_request' sin definir
collect2: error: ld returned 1 exit status
Makefile:30: fallo en las instrucciones para el objetivo 'tuntox'
make: *** [tuntox] Error 1
username@debian-server:~/tuntox$ 

I have libevent-pthreads-2.0-5 installed

[dcapeletti]

Excuse me, that problem is solved but I have a new one.

$ make
  GEN   gitversion.h
  CC    log.o
  CC    client.o
  CC    gitversion.o
  CC    mach.o
  CC    main.o
  CC    util.o
gcc -o tuntox log.o client.o gitversion.o mach.o main.o util.o -lpthread -g -pthread -lm -static -lrt -ltoxdns -ltoxencryptsave -ltoxcore -lsodium -lm -lpthread -lsodium -levent_pthreads -levent 
/usr/bin/ld: no se puede encontrar -ltoxencryptsave
main.o: En la función `do_daemonize':
/home/dcapeletti/tuntox/main.c:1091: aviso: Using 'getpwnam' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
client.o: En la función `local_bind':
/home/dcapeletti/tuntox/client.c:61: aviso: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
collect2: error: ld returned 1 exit status
Makefile:30: fallo en las instrucciones para el objetivo 'tuntox'
make: *** [tuntox] Error 1

[dcapeletti]

I've solved it with make tuntox_nostatic

[dcapeletti]

Well, I think I finally got something useful.

GNU gdb (Debian 7.12-6) 7.12.0.20161007-git
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./tuntox_nostatic...done.
(gdb) RUN��[K��[K��[K�run
Starting program: /home/dcapeletti/tuntox/tuntox_nostatic -C /home/dcapeletti/.tuntox/ -s soporte\ trillis
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
2018-01-29 22:24:27: [INFO]	Tuntox built from git commit b8c2242cafe33bda19c9774e2584be7508cb35f0
2018-01-29 22:24:27: [INFO]	Using 17621 for TCP relay port and 54415-54425 for UDP
2018-01-29 22:24:27: [INFO]	Using Tox ID: 6A27CF7A7DD03F9C05B89B02AE30EFCB2282D8F02E0EF9F669E7BE643A93154F3A1720F8F76A
2018-01-29 22:24:37: [INFO]	Connection status changed: An UDP connection has been established
2018-01-29 22:24:57: [INFO]	Accepted friend request from 9C414B8AEB9CA21D8D19E78DE2BF4F3D7C34FEB50486E911E14E12B7D66ACE77F7C376FB92DC as 0
2018-01-29 22:26:00: [INFO]	Got a request to forward data from 127.0.0.1:22
2018-01-29 22:26:00: [INFO]	Created a new tunnel object connid=1159 sockfd=9
2018-01-29 22:26:13: [INFO]	Got a request to forward data from 127.0.0.1:22
2018-01-29 22:26:13: [INFO]	Created a new tunnel object connid=49676 sockfd=10
2018-01-29 22:26:14: [INFO]	Got a request to forward data from 127.0.0.1:22
2018-01-29 22:26:14: [INFO]	Created a new tunnel object connid=35554 sockfd=11
2018-01-29 22:27:50: [WARNING]	conn closed!
2018-01-29 22:27:50: [INFO]	Deleting tunnel #1159 ptr 0x5555557abd40
2018-01-29 22:27:50: [INFO]	Deleting tunnel #49676 ptr 0x55555579cd00
2018-01-29 22:27:50: [INFO]	Deleting tunnel #35554 ptr 0x5555557654b0
2018-01-29 22:27:50: [INFO]	Deleting tunnel #21845 ptr 0x5555557654b0

Program received signal SIGSEGV, Segmentation fault.
0x000055555555a53e in tunnel_delete (t=0x5555557654b0) at main.c:158
158	        FD_CLR(t->sockfd, &master_server_fds);
(gdb) 
�[K(gdb) backtrace full
#0  0x000055555555a53e in tunnel_delete (t=0x5555557654b0) at main.c:158
No locals.
#1  0x000055555555d2aa in do_server_loop () at main.c:1045
        tunnel_list_entry = 0x555555766250
        list_tmp = 0x0
        tmp_isconnected = TOX_CONNECTION_UDP
        tox_do_interval_ms = 50
        select_rv = 1
        tv = {tv_sec = 0, tv_usec = 44433}
        tv_start = {tv_sec = 1517275670, tv_usec = 612892}
        tv_end = {tv_sec = 1517275670, tv_usec = 612563}
        ms_start = 1517275670562
        ms_end = 1517275670612
        fds = {__fds_bits = {2048, 0 <repeats 15 times>}}
        tox_packet_buf = "\242j\006\000\004\207\000\214\002\330\032\224uX\267ҽg\334\001\243\251\207\031J\343\237;s\242\375>Y\004\001\336\300Ȧ\356\033k\201k\307t\350\271\032a\202\v\237\330\020\364X\337\313Wf\037\230\273\230\214\223ۭ\363\334\001\300`!\304\017\273%([\230\271\376\254\317i|\207\034\270\375\357\202@\353\245ˀ\312gɫ\262\255ɚ#\334\066H\210\322\035\253=$\005\220@\357\025x\033\266\267Щ\314?j͙\247\035T\345\340\303w\271(Qk\254\270\362\234\342\312QVC\377\377+\000E\355\241\312\377\021\227\241{v\346\232/c\362^\320\004\320}pD\\\215Ȗ5\257S,\371п\220\023\346\311n\326F]\321i\265\267A\366\332u\225j\216`"...
        tun = 0x0
        tmp = 0x0
        connected = TOX_CONNECTION_UDP
        sent_data = 1
#2  0x000055555555e7e3 in main (argc=5, argv=0x7fffffffe228) at main.c:1536
        tox_id = "j'\317z}\320?\234\005\270\233\002\256\060\357\313\"\202\330\360.\016\371\366i\347\276d:\223\025O:\027 \370\367j"
        tox_printable_id = "6A27CF7A7DD03F9C05B89B02AE30EFCB2282D8F02E0EF9F669E7BE643A93154F3A1720F8F76A"
        tox_new_err = TOX_ERR_NEW_OK
        oc = -1
        save_size = 990
        save_data = 0x555555765300 "\370\214\233\366\377\177"
        allowed_toxid_obj = 0x0
(gdb) info registers
rax            0x555555764220	93824994394656
rbx            0x7fffffffe541	140737488348481
rcx            0xffffffffffffff98	-104
rdx            0xaaf39f8	179255800
rsi            0x155e73f	22406975
rdi            0x5579cfc0	1434046400
rbp            0x7fffffffe140	0x7fffffffe140
rsp            0x7fffffffe060	0x7fffffffe060
r8             0x7ffff7fd1700	140737353946880
r9             0x46	70
r10            0x78	120
r11            0x246	582
r12            0x555555557160	93824992244064
r13            0x7fffffffe220	140737488347680
r14            0x0	0
r15            0x0	0
rip            0x55555555e7e3	0x55555555e7e3 <main+3127>
eflags         0x10206	[ PF IF RF ]
cs             0x33	51
ss             0x2b	43
ds             0x0	0
es             0x0	0
fs             0x0	0
gs             0x0	0
(gdb) thread apply all backtrace

Thread 1 (Thread 0x7ffff7fd1700 (LWP 12484)):
#0  0x000055555555a53e in tunnel_delete (t=0x5555557654b0) at main.c:158
#1  0x000055555555d2aa in do_server_loop () at main.c:1045
#2  0x000055555555e7e3 in main (argc=5, argv=0x7fffffffe228) at main.c:1536
(gdb) quit
A debugging session is active.

	Inferior 1 [process 12484] will be killed.

Quit anyway? (y or n) y

The output dgb is attached.
gdb-tuntox.txt

Thanks.

[gjedeer]

Thanks a lot. So in terms of reproducing, you've been forwarding 3 ssh connections concurrently, then the ssh server was shut down, correct?

…

On January 30, 2018 2:33:22 AM GMT+01:00, Diego Ariel Capeletti ***@***.***> wrote: Well, I think I finally got something useful. ``` GNU gdb (Debian 7.12-6) 7.12.0.20161007-git Copyright (C) 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from ./tuntox_nostatic...done. (gdb) RUN[K[K[Krun Starting program: /home/dcapeletti/tuntox/tuntox_nostatic -C /home/dcapeletti/.tuntox/ -s soporte\ trillis [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". 2018-01-29 22:24:27: [INFO] Tuntox built from git commit b8c2242 2018-01-29 22:24:27: [INFO] Using 17621 for TCP relay port and 54415-54425 for UDP 2018-01-29 22:24:27: [INFO] Using Tox ID: 6A27CF7A7DD03F9C05B89B02AE30EFCB2282D8F02E0EF9F669E7BE643A93154F3A1720F8F76A 2018-01-29 22:24:37: [INFO] Connection status changed: An UDP connection has been established 2018-01-29 22:24:57: [INFO] Accepted friend request from 9C414B8AEB9CA21D8D19E78DE2BF4F3D7C34FEB50486E911E14E12B7D66ACE77F7C376FB92DC as 0 2018-01-29 22:26:00: [INFO] Got a request to forward data from 127.0.0.1:22 2018-01-29 22:26:00: [INFO] Created a new tunnel object connid=1159 sockfd=9 2018-01-29 22:26:13: [INFO] Got a request to forward data from 127.0.0.1:22 2018-01-29 22:26:13: [INFO] Created a new tunnel object connid=49676 sockfd=10 2018-01-29 22:26:14: [INFO] Got a request to forward data from 127.0.0.1:22 2018-01-29 22:26:14: [INFO] Created a new tunnel object connid=35554 sockfd=11 2018-01-29 22:27:50: [WARNING] conn closed! 2018-01-29 22:27:50: [INFO] Deleting tunnel #1159 ptr 0x5555557abd40 2018-01-29 22:27:50: [INFO] Deleting tunnel #49676 ptr 0x55555579cd00 2018-01-29 22:27:50: [INFO] Deleting tunnel #35554 ptr 0x5555557654b0 2018-01-29 22:27:50: [INFO] Deleting tunnel #21845 ptr 0x5555557654b0 Program received signal SIGSEGV, Segmentation fault. 0x000055555555a53e in tunnel_delete (t=0x5555557654b0) at main.c:158 158 FD_CLR(t->sockfd, &master_server_fds); (gdb) [K(gdb) backtrace full #0 0x000055555555a53e in tunnel_delete (t=0x5555557654b0) at main.c:158 No locals. #1 0x000055555555d2aa in do_server_loop () at main.c:1045 tunnel_list_entry = 0x555555766250 list_tmp = 0x0 tmp_isconnected = TOX_CONNECTION_UDP tox_do_interval_ms = 50 select_rv = 1 tv = {tv_sec = 0, tv_usec = 44433} tv_start = {tv_sec = 1517275670, tv_usec = 612892} tv_end = {tv_sec = 1517275670, tv_usec = 612563} ms_start = 1517275670562 ms_end = 1517275670612 fds = {__fds_bits = {2048, 0 <repeats 15 times>}} tox_packet_buf = "\242j\006\000\004\207\000\214\002\330\032\224uX\267ҽg\334\001\243\251\207\031J\343\237;s\242\375>Y\004\001\336\300Ȧ\356\033k\201k\307t\350\271\032a\202\v\237\330\020\364X\337\313Wf\037\230\273\230\214\223ۭ\363\334\001\300`!\304\017\273%([\230\271\376\254\317i|\207\034\270\375\357\202@\353\245ˀ\312gɫ\262\255ɚ#\334\066H\210\322\035\253=$\005\220@\357\025x\033\266\267Щ\314?j͙\247\035T\345\340\303w\271(Qk\254\270\362\234\342\312QVC\377\377+\000E\355\241\312\377\021\227\241{v\346\232/c\362^\320\004\320}pD\\\215Ȗ5\257S,\371п\220\023\346\311n\326F]\321i\265\267A\366\332u\225j\216`"... tun = 0x0 tmp = 0x0 connected = TOX_CONNECTION_UDP sent_data = 1 #2 0x000055555555e7e3 in main (argc=5, argv=0x7fffffffe228) at main.c:1536 tox_id = "j'\317z}\320?\234\005\270\233\002\256\060\357\313\"\202\330\360.\016\371\366i\347\276d:\223\025O:\027 \370\367j" tox_printable_id = "6A27CF7A7DD03F9C05B89B02AE30EFCB2282D8F02E0EF9F669E7BE643A93154F3A1720F8F76A" tox_new_err = TOX_ERR_NEW_OK oc = -1 save_size = 990 save_data = 0x555555765300 "\370\214\233\366\377\177" allowed_toxid_obj = 0x0 (gdb) info registers rax 0x555555764220 93824994394656 rbx 0x7fffffffe541 140737488348481 rcx 0xffffffffffffff98 -104 rdx 0xaaf39f8 179255800 rsi 0x155e73f 22406975 rdi 0x5579cfc0 1434046400 rbp 0x7fffffffe140 0x7fffffffe140 rsp 0x7fffffffe060 0x7fffffffe060 r8 0x7ffff7fd1700 140737353946880 r9 0x46 70 r10 0x78 120 r11 0x246 582 r12 0x555555557160 93824992244064 r13 0x7fffffffe220 140737488347680 r14 0x0 0 r15 0x0 0 rip 0x55555555e7e3 0x55555555e7e3 <main+3127> eflags 0x10206 [ PF IF RF ] cs 0x33 51 ss 0x2b 43 ds 0x0 0 es 0x0 0 fs 0x0 0 gs 0x0 0 (gdb) thread apply all backtrace [gdb-tuntox.txt](https://github.com/gjedeer/tuntox/files/1675935/gdb-tuntox.txt) Thread 1 (Thread 0x7ffff7fd1700 (LWP 12484)): #0 0x000055555555a53e in tunnel_delete (t=0x5555557654b0) at main.c:158 #1 0x000055555555d2aa in do_server_loop () at main.c:1045 #2 0x000055555555e7e3 in main (argc=5, argv=0x7fffffffe228) at main.c:1536 (gdb) quit A debugging session is active. Inferior 1 [process 12484] will be killed. Quit anyway? (y or n) y ``` The output dgb is attached. Thanks. -- You are receiving this because you commented. Reply to this email directly or view it on GitHub: #50 (comment)

-- Sent from my Android device with K-9 Mail. Please excuse my brevity.

[gjedeer]

I just tried the scenario i described above and no crash. Also running a few SSH sessions for several minutes doesn't seem to crash it.

I see it's a double-free but can't figure out how it's happening. Maybe running with -d -d will give more data.

[dcapeletti]

I explain step by step how I managed to cause the error.

• On the server side I install x2goserver x2goserver-xsession packages to start remote support via x2goclient.

• After the server-side packages were installed, I open tuntox in server mode.

• Then on the client side, I open a connection to the server using port 22
  . /tuntox-x64 -i 6A27CF7A7A7DD03F9C05B89B89B02AE30EFCB2282D8F02E0EF9F669E7BE643A93154F3A1720F8F76A -s "password" -L222222:127.0.0.1:22

• The connection is successfully opened. Then I open the x2goclient and create a GNOME session. The connection is successful and I can operate on the remote desktop. At this point, that's when the server starts to create the tunnels.

• After finishing working with the remote desktop without any problems, I close the x2goagent client and the tuntox server crashes immediately. But that does not always happen, at least sometimes it does not happen the first time, but it does happen next time.

Among the basic features of x2go, is that traffic is safe because it is sent over SSH. See https://wiki.x2go.org/doku.php/doc:newtox2go

[dcapeletti]

Well, I tried to open 3 ssh sessions in three terminals, I work them a bit and when I press Ctrl + D to close the connection in the first or second terminal, the tuntox server has a problem. The gdb output is attached.
The ssh server never closes.

gdb-tuntox-terminal-ssh.txt

[dcapeletti]

Attached output gbd of tuntox server mode using the -d option.
One output corresponds to the x2go connection and another output corresponds to the use of 3 ssh terminals that connect to the tuntox server. When Ctrl+D is pressed to close a terminal session, sometimes the first, second or last, the tuntox server has problems.

gdb-tuntox-x2go.txt
gdb-tuntox-3-ssh-conections.txt

[dcapeletti]

Video demonstration of the error.

[gjedeer]

Thanks for the detailed reporting, I was able to reproduce the problem and fix it.

Please test by building from git master or using this binary https://w1r3.net/hfxwpu.bin

For future (since you seem to be a frequent user, glad to see that!) - using -d twice (-d -d) generates more useful information for me.

[dcapeletti]

Thank you very much, tuntox is very useful for me, the problem is solved. Next time I will send with the -d -d option. Although it would seem to work a bit slower, this issue can be closed.