[GUACAMOLE-1697] guacd segfaults in rfbClientCleanup

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Invalid
• Affects Version/s: 1.3.0
• Component/s: guacd
• Assignee: Unassigned
• Reporter: Dmitry Katsubo
• Created: 14/Oct/22 09:04
• Updated: 14/Oct/22 17:46
• Resolved: 14/Oct/22 17:46

Description

The issue is reproducible each time I connect to VNC via guacd. The screen in browser window freezes but after guacd restarts, it continues to function properly.
Core dump:

TIME                            PID   UID   GID SIG COREFILE  EXE
Mon 2022-10-10 10:08:28 CEST 1881494   502   502  11 present   /usr/sbin/guacd

Last core dump info:

           PID: 1881494 (guacd)
           UID: 502 (guacd)
           GID: 502 (guacd)
        Signal: 11 (SEGV)
     Timestamp: Mon 2022-10-10 10:08:28 CEST (20h ago)
  Command Line: /usr/sbin/guacd -b 127.0.0.1 -l 4822 -p /var/run/guacd/guacd.pid
    Executable: /usr/sbin/guacd
 Control Group: /system.slice/guacd.service
          Unit: guacd.service
         Slice: system.slice
       Storage: /var/lib/systemd/coredump/core.guacd.502.056edc242bfa40b5a8014aa81b8e3ec8.1881494.1665389308000000.zst
       Message: Process 1881494 (guacd) of user 502 dumped core.
                
                Stack trace of thread 1885301:
                #0  0x00007faf1a69873c cfree (libc.so.6 + 0x8a73c)
                #1  0x00007faf18e3491a rfbClientCleanup (libvncclient.so.1 + 0x1b91a)
                #2  0x00007faf18e4b581 guac_vnc_client_free_handler (libguac-client-vnc.so + 0x9581)
                #3  0x00007faf1a890ab2 guac_client_free (libguac.so.19 + 0x8ab2)
                #4  0x000056166c7917b5 n/a (guacd + 0x47b5)
                #5  0x00007faf1a86eea7 start_thread (libpthread.so.0 + 0x8ea7)
                #6  0x00007faf1a70bdef __clone (libc.so.6 + 0xfddef)
                
                Stack trace of thread 1881497:
                #0  0x00007faf1a6d3c61 clock_nanosleep (libc.so.6 + 0xc5c61)
                #1  0x00007faf1a6d9443 __nanosleep (libc.so.6 + 0xcb443)
                #2  0x00007faf1a896122 n/a (libguac.so.19 + 0xe122)
                #3  0x00007faf1a86eea7 start_thread (libpthread.so.0 + 0x8ea7)
                #4  0x00007faf1a70bdef __clone (libc.so.6 + 0xfddef)
                
                Stack trace of thread 1881494:
                #0  0x00007faf1a875ad8 pthread_cond_timedwait@@GLIBC_2.3.2 (libpthread.so.0 + 0xfad8)
                #1  0x000056166c791bff n/a (guacd + 0x4bff)
                #2  0x000056166c790ec9 n/a (guacd + 0x3ec9)
                #3  0x00007faf1a86eea7 start_thread (libpthread.so.0 + 0x8ea7)
                #4  0x00007faf1a70bdef __clone (libc.so.6 + 0xfddef)

Problematic guacd v1.3.0-1 from Debian bullseye. The previous v0.9.9 is known to work without this issue.