Bug report - segfault sshd

[John Fawcett]

On 12/23/2016 01:10 PM, John Fawcett wrote:
> When logging in via ssh with user root and password authentication I get
> a segfault in sshd. The problem is 100% reproduceable - I cannot login
> remotely at all. Any help appreciated in trying to get this addressed.
>
> This is a centos 7.3 with all the latest updates applied
>
> openssh-6.6.1p1-31.el7.x86_64
>
> Here's a backtrace captured by running sshd under gdb.
>
> /usr/sbin/sshd -d
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib64/libthread_db.so.1".
> process 14806 is executing new program: /usr/sbin/sshd
> Missing separate debuginfos, use: debuginfo-install
> keyutils-libs-1.5.8-3.el7.x86_64
> nss-softokn-freebl-3.16.2.3-14.4.el7.x86_64 pcre-8.32-15.el7_2.1.x86_64
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib64/libthread_db.so.1".
> Detaching after fork from child process 14810.
>
> Program received signal SIGSEGV, Segmentation fault.
> __strcmp_ssse3 () at ../sysdeps/x86_64/strcmp.S:212
> 212        movlpd    (%rdi), %xmm1
> Missing separate debuginfos, use: debuginfo-install
> bzip2-libs-1.0.6-13.el7.x86_64 cracklib-2.9.0-11.el7.x86_64
> elfutils-libelf-0.166-2.el7.x86_64 elfutils-libs-0.166-2.el7.x86_64
> keyutils-libs-1.5.8-3.el7.x86_64 libattr-2.4.46-12.el7.x86_64
> libcap-2.22-8.el7.x86_64 libgcc-4.8.5-11.el7.x86_64
> libpwquality-1.2.3-4.el7.x86_64
> nss-softokn-freebl-3.16.2.3-14.4.el7.x86_64 pcre-8.32-15.el7_2.1.x86_64
> systemd-libs-219-30.el7_3.6.x86_64 xz-libs-5.2.2-1.el7.x86_64
> #0  __strcmp_ssse3 () at ../sysdeps/x86_64/strcmp.S:212
> #1  0x0000555555584f2f in sshpam_auth_passwd
> (authctxt=authctxt at entry=0x55555581fdb0,
> password=password at entry=0x555555839900 "************") at auth-pam.c:1207
> #2  0x000055555556446b in auth_password (authctxt=0x55555581fdb0,
> password=password at entry=0x555555839900 "************") at auth-passwd.c:149
> #3  0x0000555555578daa in mm_answer_authpassword (sock=5,
> m=0x7fffffffda10) at monitor.c:860
> #4  0x000055555557b9b1 in monitor_read
> (pmonitor=pmonitor at entry=0x55555581efb0, ent=0x55555580a390
> <mon_dispatch_proto20+80>, pent=pent at entry=0x7fffffffda78) at monitor.c:586
> #5  0x000055555557c7bc in monitor_child_preauth
> (_authctxt=_authctxt at entry=0x55555581fdb0, pmonitor=0x55555581efb0) at
> monitor.c:374
> #6  0x00005555555615f5 in privsep_preauth (authctxt=0x55555581fdb0) at
> sshd.c:681
> #7  main (ac=<optimized out>, av=<optimized out>) at sshd.c:2094
>
I reinstalled openssh-server package and it is now working. I am
assuming there was some corruption.

John