Bug#888884: segfault for no obvious reason on rcp from remote host

[Hiroyuki YAMAMORI]

Dear Maintainer,

It will fix with the following patch.

--- netkit-rsh-0.17/rcp/rcp.c
+++ new/rcp/rcp.c
@@ -889,7 +889,11 @@
fprintf(fp, "%c", 0x01);
vfprintf(fp, fmt, ap);
fflush(fp);
-   if (!iamremote) vfprintf(stderr, fmt, ap);
+   if (!iamremote) {
+   va_end(ap);
+   va_start(ap, fmt);
+   vfprintf(stderr, fmt, ap);
+   }
 
va_end(ap);
 }

Bug#366535 will also be fixed with this patch.

Thank you,
Hiroyuki YAMAMORI

Bug#888884: segfault for no obvious reason on rcp from remote host

[Yaroslav Halchenko]

Package: rsh-client
Version: 0.17-15
Severity: important

I was truly amazed to find an 11 year old segfault-reporting #366535 but since
my traceback/use case is different, decided that it might be a different
issue.

We use rcp/rsh on our local cluster between nodes.  rcp "doesn't work":

root@head3:~# gdb --args /usr/bin/rcp head1:/etc/singularity/singularity.conf 
/etc/singularity/singularity.conf
GNU gdb (Debian 7.7.1+dfsg-5) 7.7.1
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and "show warranty" for details.
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Reading symbols from /usr/bin/rcp...(no debugging symbols found)...done.
(gdb) r
Starting program: /usr/bin/rcp head1:/etc/singularity/singularity.conf 
/etc/singularity/singularity.conf

Program received signal SIGSEGV, Segmentation fault.
0x7f2e68b0bdcc in _IO_vfprintf_internal (s=, 
format=, ap=)
at vfprintf.c:1642
1642vfprintf.c: No such file or directory.
(gdb) bt
#0  0x7f2e68b0bdcc in _IO_vfprintf_internal (s=, 
format=, ap=)
at vfprintf.c:1642
#1  0x7f2e68b0cb01 in buffered_vfprintf (s=s@entry=0x7f2e68e67060 
<_IO_2_1_stderr_>, 
format=format@entry=0x4036ed "rcp: protocol screwup: %s\n", 
args=args@entry=0x7ffec335c380)
at vfprintf.c:2348
#2  0x7f2e68b0737e in _IO_vfprintf_internal (s=0x7f2e68e67060 
<_IO_2_1_stderr_>, 
format=0x4036ed "rcp: protocol screwup: %s\n", ap=0x7ffec335c380) at 
vfprintf.c:1296
#3  0x00401672 in ?? ()
#4  0x0040240d in ?? ()
#5  0x00403357 in ?? ()
#6  0x7f2e68ae2b45 in __libc_start_main (main=0x402a70, argc=3, 
argv=0x7ffec335e768, init=, 
fini=, rtld_fini=, stack_end=0x7ffec335e758) 
at libc-start.c:287
#7  0x004014b9 in ?? ()
#8  0x7ffec335e758 in ?? ()
#9  0x001c in ?? ()
#10 0x0003 in ?? ()
#11 0x7ffec335ecb6 in ?? ()
#12 0x7ffec335ecc3 in ?? ()
#13 0x7ffec335eceb in ?? ()
#14 0x in ?? ()

rsh head1   works fine

rcp the file from head1 to head3 works:
root@head1:/etc/singularity# rcp $PWD/singularity.conf 
head3:$PWD/singularity.conf
root@head1:/etc/singularity# echo $?
0


-- System Information:
Debian Release: 8.5
  APT prefers oldstable
  APT policy: (500, 'oldstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: sysvinit (via /sbin/init)

Versions of packages rsh-client depends on:
ii  libc6  2.19-18+deb8u4

rsh-client recommends no packages.

rsh-client suggests no packages.

-- no debconf information