Description of problem: when glibc tries to load nss libraries in a chroot
environment where those libraries don't exist, the library segfaults.  this is
showing up when running an rsync server that has chroot enabled (default), files
owned by non root (otherwise getpwuid isn't called), and a remote client that
enables -o (to preserve ownership).


Version-Release number of selected component (if applicable):
glibc-2.3.4-2

How reproducible:
every time.


Steps to Reproduce:
1. chroot
2. call getpwuid
3.
  
Actual results:
segfault

Expected results:
getpwuid should return null to indicate that it can't map the uid.

Additional info:

c code to exhibit problem (must be run as root for chroot to work):

#include <sys/types.h>
#include <pwd.h>

main()
{
        struct passwd *p;

        chroot("/tmp");
        chdir("/");
        p = getpwuid(666);
        if (p) {
                printf("%s\n", p->pw_name);
        }
        exit(0);
}

strace of invocation:
execve("./test", ["./test"], [/* 37 vars */]) = 0
uname({sys="Linux", node="jupiter.spiretech.com", ...}) = 0
brk(0)                                  = 0xa03e000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=115297, ...}) = 0
old_mmap(NULL, 115297, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7fe3000
close(3)                                = 0
open("/lib/tls/libc.so.6", O_RDONLY)    = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0 ov\000"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1212936, ...}) = 0
old_mmap(0x752000, 1215644, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x752000
old_mmap(0x875000, 16384, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x123000) = 0x875000
old_mmap(0x879000, 7324, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x879000
close(3)                                = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb7fe2000
mprotect(0x875000, 4096, PROT_READ)     = 0
mprotect(0x74a000, 4096, PROT_READ)     = 0
set_thread_area({entry_number:-1 -> 6, base_addr:0xb7fe2940, limit:1048575,
seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0,
useable:1}) = 0
munmap(0xb7fe3000, 115297)              = 0
chroot("/tmp")                          = 0
chdir("/")                              = 0
brk(0)                                  = 0xa03e000
brk(0xa05f000)                          = 0xa05f000
socket(PF_FILE, SOCK_STREAM, 0)         = 3
fcntl64(3, F_GETFL)                     = 0x2 (flags O_RDWR)
fcntl64(3, F_SETFL, O_RDWR|O_NONBLOCK)  = 0
connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"}, 110) = -1 ENOENT
(No such file or directory)
close(3)                                = 0
socket(PF_FILE, SOCK_STREAM, 0)         = 3
fcntl64(3, F_GETFL)                     = 0x2 (flags O_RDWR)
fcntl64(3, F_SETFL, O_RDWR|O_NONBLOCK)  = 0
connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"}, 110) = -1 ENOENT
(No such file or directory)
close(3)                                = 0
open("/etc/nsswitch.conf", O_RDONLY)    = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = -1 ENOENT (No such file or directory)
open("/lib/tls/i686/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such
file or directory)
stat64("/lib/tls/i686/sse2", 0xbff98984) = -1 ENOENT (No such file or directory)
open("/lib/tls/i686/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/lib/tls/i686", 0xbff98984)     = -1 ENOENT (No such file or directory)
open("/lib/tls/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/lib/tls/sse2", 0xbff98984)     = -1 ENOENT (No such file or directory)
open("/lib/tls/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/lib/tls", 0xbff98984)          = -1 ENOENT (No such file or directory)
open("/lib/i686/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/lib/i686/sse2", 0xbff98984)    = -1 ENOENT (No such file or directory)
open("/lib/i686/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/lib/i686", 0xbff98984)         = -1 ENOENT (No such file or directory)
open("/lib/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/lib/sse2", 0xbff98984)         = -1 ENOENT (No such file or directory)
open("/lib/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or directory)
stat64("/lib", 0xbff98984)              = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/i686/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such
file or directory)
stat64("/usr/lib/tls/i686/sse2", 0xbff98984) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/i686/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file
or directory)
stat64("/usr/lib/tls/i686", 0xbff98984) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file
or directory)
stat64("/usr/lib/tls/sse2", 0xbff98984) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/usr/lib/tls", 0xbff98984)      = -1 ENOENT (No such file or directory)
open("/usr/lib/i686/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such
file or directory)
stat64("/usr/lib/i686/sse2", 0xbff98984) = -1 ENOENT (No such file or directory)
open("/usr/lib/i686/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/usr/lib/i686", 0xbff98984)     = -1 ENOENT (No such file or directory)
open("/usr/lib/sse2/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/usr/lib/sse2", 0xbff98984)     = -1 ENOENT (No such file or directory)
open("/usr/lib/libnss_compat.so.2", O_RDONLY) = -1 ENOENT (No such file or
directory)
stat64("/usr/lib", 0xbff98984)          = -1 ENOENT (No such file or directory)
--- SIGSEGV (Segmentation fault) @ 0 (0) ---
+++ killed by SIGSEGV (core dumped) +++