Public bug reported:
Binary package hint: libc6
In Kubuntu Edgy Eft on amd64 as root:
su - release
Segmentation fault
User "release" does not exist in local password file, but is an NIS user.
Problem appears to be related to user not found in
/etc/passwd.
/etc/nsswitch.conf:
passwd: files nisplus nis compat
group: files nisplus nis compat
shadow: files nisplus nis compat
hosts: files dns
networks: files dns
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
automount: nisplus nis files
User exists in NIS:
ypmatch -k release passwd.byname
release release:sMz8EU80VVu2w:519:101:SSL Controlled Build Account:/home/release
all /etc/pam.d files are unmodified from install.
Installed libc6 is libc6-dbg. Segfault was first observed in
standard version.
>From build of "login" package produced thus:
cd /usr/src
mkdir login
cd login
apt-get build-dep login
apt-get source login
make -f debian/rules binary
Debug as root elicits segv:
cd /usr/src/login/shadow-4.0.16/src
./su - release
Segmentation fault
gdb su
[ gdb banner announcement ]
(gdb) set args - release
(gdb) run
Starting program: /usr/src/login/shadow-4.0.16/src/su - release
Program received signal SIGSEGV, Segmentation fault.
0x00002b4f84b2a0d0 in _nss_files_getpwnam_r () from /lib/libnss_files.so.2
(gdb) bt
#0 0x00002b4f84b2a0d0 in _nss_files_getpwnam_r () from /lib/libnss_files.so.2
#1 0x00002b4f84871b15 in getpwnam_r@@GLIBC_2.2.5 () from /lib/libc.so.6
#2 0x00002b4f84871520 in getpwnam () from /lib/libc.so.6
#3 0x00002b4f852bcec0 in pam_sm_setcred () from /lib/security/pam_env.so
#4 0x00002b4f845d61d5 in _pam_dispatch () from /lib/libpam.so.0
#5 0x0000000000403474 in main (argc=<value optimized out>, argv=<value
optimized out>) at su.c:799
If I add a user "release" to the local password file:
su - release
$
tail -1 /etc/passwd:
release:!:519:101:SSL Controlled Build Account:/home/release
cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 15
model : 65
model name : Dual-Core AMD Opteron(tm) Processor 2212
stepping : 2
cpu MHz : 2010.298
cache size : 1024 KB
...
Problem is elicited when any user runs "su username" where "username" is
not in local password file.
This segfault appears to be substantially similary to a posibly related fault
obtained running rsync of files owned by group "release", an NIS group not
found in the local "group" file, which appears in
getgrnam(), which I will report later today.
** Affects: glibc (Ubuntu)
Importance: Undecided
Status: Unconfirmed
--
segfault in gepwnam() under amd64
https://launchpad.net/bugs/72882
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