Aw: rsync buffer overflow detected

[devzero at web.de]

What's the value of "i" when this happens and what are the system ulimit values for the user running that?

Roland



> Gesendet: Freitag, 14. April 2017 um 19:22 Uhr
> Von: "Boris Savelev via rsync" <rsync at lists.samba.org>
> An: rsync at lists.samba.org
> Betreff: rsync buffer overflow detected
>
> Hello!
> 
> I use rsync from python on my Debian Jessie amd64 and get this error:
> *** buffer overflow detected ***: <snip>/rsync terminated
> ======= Backtrace: =========
> /lib/x86_64-linux-gnu/libc.so.6(+0x731af)[0x7ffff78971af]
> /lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x37)[0x7ffff791caa7]
> /lib/x86_64-linux-gnu/libc.so.6(+0xf6cc0)[0x7ffff791acc0]
> /lib/x86_64-linux-gnu/libc.so.6(+0xf8a17)[0x7ffff791ca17]
> <snip>/rsync(+0x30c78)[0x555555584c78]
> <snip>/rsync(+0x31cfe)[0x555555585cfe]
> <snip>/rsync(+0x31ef6)[0x555555585ef6]
> <snip>/rsync(+0x336ed)[0x5555555876ed]
> <snip>/rsync(+0x22417)[0x555555576417]
> <snip>/rsync(+0x2395e)[0x55555557795e]
> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5)[0x7ffff7845b45]
> <snip>/rsync(+0x7f89)[0x55555555bf89]
> 
> I guess that problem is about too many open fds
> STR for this is a small script on python:
> import os
> import subprocess
> 
> F = 'test'
> OPENS = 1600
> 
> cmd = [
>     #'gdb', '--args',
>     './rsync',
>     '-aviH',
>     '/etc/passwd',
>     '/tmp/passwd'
> ]
> 
> for i in xrange(OPENS):
>     fd = os.open(F, os.O_WRONLY | os.O_CREAT)
> print(cmd)
> subprocess.check_call(cmd)
> 
> I rebuild rsync-3.1.1 from Debian source with debug and -O1 and get bt from gdb:
> (gdb) bt
> #0  0x00007ffff7859067 in __GI_raise (sig=sig at entry=6) at
> ../nptl/sysdeps/unix/sysv/linux/raise.c:56
> #1  0x00007ffff785a448 in __GI_abort () at abort.c:89
> #2  0x00007ffff78971b4 in __libc_message (do_abort=do_abort at entry=2,
> fmt=fmt at entry=0x7ffff7989cb3 "*** %s ***: %s terminated\n")
>     at ../sysdeps/posix/libc_fatal.c:175
> #3  0x00007ffff791caa7 in __GI___fortify_fail
> (msg=msg at entry=0x7ffff7989c4a "buffer overflow detected") at
> fortify_fail.c:31
> #4  0x00007ffff791acc0 in __GI___chk_fail () at chk_fail.c:28
> #5  0x00007ffff791ca17 in __fdelt_chk (d=d at entry=1606) at fdelt_chk.c:25
> #6  0x0000555555584c78 in safe_read (fd=fd at entry=1606,
> buf=buf at entry=0x7fffffffa810 "\037", len=len at entry=4) at io.c:245
> #7  0x0000555555585cfe in read_buf (f=f at entry=1606,
> buf=buf at entry=0x7fffffffa810 "\037", len=len at entry=4) at io.c:1815
> #8  0x0000555555585ef6 in read_int (f=f at entry=1606) at io.c:1711
> #9  0x00005555555876ed in setup_protocol (f_out=1605, f_in=1606) at compat.c:158
> #10 0x0000555555576417 in client_run (f_in=1606, f_out=1605,
> pid=24793, argc=1, argv=0x5555557d5240) at main.c:1128
> #11 0x000055555557795e in start_client (argv=0x5555557d5240, argc=1)
> at main.c:1423
> #12 main (argc=2, argv=0x5555557d5240) at main.c:1651
> 
> It looks like a bug, but I'm not sure)
> 
> --
> Boris
> 
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