[tor-bugs] #5078 [Obfsproxy]: Debug logging segfault

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#5078: Debug logging segfault
-----------------------+----------------------------------------------------
 Reporter:  twilde     |          Owner:  asn
     Type:  defect     |         Status:  new
 Priority:  normal     |      Milestone:     
Component:  Obfsproxy  |        Version:     
 Keywords:             |         Parent:     
   Points:             |   Actualpoints:     
-----------------------+----------------------------------------------------
 When obfsproxy is configured with the following in torrc:

 {{{
 servertransportplugin obfs2 exec /usr/local/bin/obfsproxy --managed --log-
 file=/var/log/tor/obfsproxy.log --log-min-severity=debug
 }}}

 It immediately segfaults on startup, with the following stack trace:

 {{{
 Core was generated by `/usr/local/bin/obfsproxy --managed --log-
 file=/var/log/tor/obfsproxy.log --log-'.
 Program terminated with signal 11, Segmentation fault.
 #0  0x0000003ec1879b80 in strlen () from /lib64/libc.so.6
 (gdb) bt
 #0  0x0000003ec1879b80 in strlen () from /lib64/libc.so.6
 #1  0x0000003ec1846cb9 in vfprintf () from /lib64/libc.so.6
 #2  0x0000003ec18699da in vsnprintf () from /lib64/libc.so.6
 #3  0x00000000004058b3 in obfs_vsnprintf (
     str=0x7fff872eb5e8 "0123456789abcdefghijklmnopqrstuvwxyz 0.0.0.0:42401
 \301>", size=1, format=0x7fff872ebb08 " \337\314\020\377\377\377\377\002",
 args=0x0)
     at src/util.c:304
 #4  0x0000000000405a0a in logv (severity=<value optimized out>,
     format=0x40af0a "%s %s %s:%hu\n", ap=0x7fff872eba10) at src/util.c:530
 #5  0x000000000040243e in print_protocol_line (
     format=0x40af0a "%s %s %s:%hu\n") at src/managed.c:152
 #6  0x0000000000402570 in print_method_line (proxy=0x10cbf010)
     at src/managed.c:331
 #7  open_listeners_managed (proxy=0x10cbf010) at src/managed.c:540
 #8  0x0000000000402b5f in launch_server_listeners () at src/managed.c:594
 #9  launch_listeners () at src/managed.c:650
 #10 launch_managed_proxy () at src/managed.c:681
 #11 0x0000000000402087 in obfs_main (argc=281861920, argv=0x1)
     at src/main.c:265
 #12 0x0000003ec181d994 in __libc_start_main () from /lib64/libc.so.6
 #13 0x0000000000401de9 in _start ()
 }}}

 100% reproducible in my environment.  Core file available if needed.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5078>
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