Ubuntu
schroot package

  1. Bug #486944
  2. Comment #11

Comment 11 for bug 486944

Revision history for this message
Brian May (brian-microcomaustralia) wrote : Re: [Bug 486944] Re: Different permission denied errors

You previous email didn't seem to come out on Launchpad, so I will
just reply here.

On 7 March 2010 06:59, Roger Leigh <email address hidden> wrote:
> This seems rather more likely than something intrinsic to schroot.
> You should be able to confirm this with gdb by breaking on calls
> to setuid and then doing a backtrace.  schroot itself only calls
> setuid() prior to invoking the command in the chroot, and then again to
> check that privs were dropped correctly.  This should tell us which
> library/function called it.

What gdb shows me seems just so weird, I am just going to print the
results here, without trying to make sense of them.

Note I installed the -dbg packages for libgcrypt and libgnutls.

GNU gdb (GDB) 7.0-ubuntu
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/bin/schroot...(no debugging symbols found)...done.
(gdb) set args -c lenny
(gdb) r
Starting program: /usr/bin/schroot -c lenny
[Thread debugging using libthread_db enabled]
E: /dev/vg/schroot-lenny: Failed to stat file: Permission denied

Program exited normally.
(gdb) break setuid
Breakpoint 1 at 0x7f0fb948ae80
(gdb) r
Starting program: /usr/bin/schroot -c lenny
[Thread debugging using libthread_db enabled]

Breakpoint 1, 0x00007fc557984e80 in setuid () from /lib/libc.so.6
(gdb) bt
#0 0x00007fc557984e80 in setuid () from /lib/libc.so.6
#1 0x00007fc553cf3004 in lock_pool (n=<value optimized out>) at secmem.c:296
#2 secmem_init (n=<value optimized out>) at secmem.c:477
#3 0x00007fc553cf31ba in _gcry_secmem_malloc_internal (size=128) at
secmem.c:509
#4 0x00007fc553cf3248 in _gcry_secmem_malloc (size=128) at secmem.c:544
#5 0x00007fc553cee74d in do_malloc (n=10003, flags=32768,
mem=0x7fff1951a9a8) at global.c:730
#6 0x00007fc553cee77c in _gcry_malloc_secure (n=10003) at global.c:769
#7 0x00007fc553d00fd0 in md_open (h=0x7fff1951aa18, algo=1,
secure=<value optimized out>, hmac=<value optimized out>) at md.c:487
#8 0x00007fc553d010fa in _gcry_md_open (h=0x7fff1951ab08, algo=32768,
flags=<value optimized out>) at md.c:530
#9 0x00007fc5543c09af in wrap_gcry_mac_init (algo=<value optimized
out>, ctx=0x2713) at mac-libgcrypt.c:42
#10 0x00007fc5543a6ee7 in _gnutls_hmac_init (dig=0x7fff1951ab00,
algorithm=GNUTLS_MAC_MD5, key=0x2112350, keylen=24) at
gnutls_hash_int.c:277
#11 0x00007fc5543b7b38 in _gnutls_P_hash (algorithm=<value optimized
out>, secret=<value optimized out>, secret_size=<value optimized out>,
seed=<value optimized out>, seed_size=<value optimized out>,
total_bytes=<value optimized out>, ret=0x7fff1951ad60
"\354\255Q\031\377\177") at gnutls_state.c:811
#12 0x00007fc5543b7d8a in _gnutls_PRF (session=<value optimized out>,
secret=<value optimized out>, secret_size=<value optimized out>,
label=<value optimized out>, label_size=<value optimized out>,
    seed=0x7fff1951b160
"K\222\352\274\311\367\273\213Y\314\356\252Lu-\325y\341\265\300,\t\311/\342\237\066\v\025\031l\373K\222\352\274/g\363\270\370\020\037[:\347b\037\033\223\322\070\257bɊ\271\340\f\342]\030\212=\001",
seed_size=<value optimized out>, total_bytes=48, ret=0x210c692) at
gnutls_state.c:926
#13 0x00007fc5543a55ff in generate_normal_master (session=0x210c670,
keep_premaster=0) at gnutls_kx.c:155
#14 0x00007fc5543b037b in _gnutls_connection_state_init
(session=0x2713) at gnutls_constate.c:434
#15 0x00007fc5543a11c8 in _gnutls_send_handshake_final
(session=0x210c670, init=1) at gnutls_handshake.c:2472
#16 0x00007fc5543a13a5 in _gnutls_handshake_common (session=0x210c670)
at gnutls_handshake.c:2693
#17 0x00007fc5543a2a37 in gnutls_handshake (session=0x210c670) at
gnutls_handshake.c:2297
#18 0x00007fc554c9d40e in ?? () from /usr/lib/libldap_r-2.4.so.2
#19 0x00007fc554c9c1d2 in ?? () from /usr/lib/libldap_r-2.4.so.2
#20 0x00007fc554c9c433 in ldap_int_tls_start () from /usr/lib/libldap_r-2.4.so.2
#21 0x00007fc554c9c58e in ldap_start_tls_s () from /usr/lib/libldap_r-2.4.so.2
#22 0x00007fc554eb2b84 in ?? () from /lib/security/pam_ldap.so
#23 0x00007fc554eb4f37 in ?? () from /lib/security/pam_ldap.so
#24 0x00007fc554eb51a1 in ?? () from /lib/security/pam_ldap.so
#25 0x00007fc554eb5cc1 in pam_sm_acct_mgmt () from /lib/security/pam_ldap.so
#26 0x00007fc558f71bde in ?? () from /lib/libpam.so.0
#27 0x000000000048d7a0 in ?? ()
#28 0x0000000000477f56 in ?? ()
#29 0x000000000042cabb in ?? ()
#30 0x0000000000422ef7 in ?? ()
#31 0x0000000000414089 in ?? ()
#32 0x00007fc5578feabd in __libc_start_main () from /lib/libc.so.6
#33 0x0000000000411b29 in ?? ()
#34 0x00007fff1951cda8 in ?? ()
#35 0x000000000000001c in ?? ()
#36 0x0000000000000003 in ?? ()
#37 0x00007fff1951e6df in ?? ()
#38 0x00007fff1951e6f0 in ?? ()
#39 0x00007fff1951e6f3 in ?? ()
#40 0x0000000000000000 in ?? ()
(gdb) c
Continuing.

Breakpoint 1, 0x00007fc557984e80 in setuid () from /lib/libc.so.6
(gdb) bt
#0 0x00007fc557984e80 in setuid () from /lib/libc.so.6
#1 0x00007fc553cf301f in lock_pool (n=<value optimized out>) at secmem.c:296
#2 secmem_init (n=<value optimized out>) at secmem.c:477
#3 0x00007fc553cf31ba in _gcry_secmem_malloc_internal (size=128) at
secmem.c:509
#4 0x00007fc553cf3248 in _gcry_secmem_malloc (size=128) at secmem.c:544
#5 0x00007fc553cee74d in do_malloc (n=0, flags=0, mem=0x7fff1951a9a8)
at global.c:730
#6 0x00007fc553cee77c in _gcry_malloc_secure (n=0) at global.c:769
#7 0x00007fc553d00fd0 in md_open (h=0x7fff1951aa18, algo=1,
secure=<value optimized out>, hmac=<value optimized out>) at md.c:487
#8 0x00007fc553d010fa in _gcry_md_open (h=0x7fff1951ab08, algo=0,
flags=<value optimized out>) at md.c:530
#9 0x00007fc5543c09af in wrap_gcry_mac_init (algo=<value optimized
out>, ctx=0x0) at mac-libgcrypt.c:42
#10 0x00007fc5543a6ee7 in _gnutls_hmac_init (dig=0x7fff1951ab00,
algorithm=GNUTLS_MAC_MD5, key=0x2112350, keylen=24) at
gnutls_hash_int.c:277
#11 0x00007fc5543b7b38 in _gnutls_P_hash (algorithm=<value optimized
out>, secret=<value optimized out>, secret_size=<value optimized out>,
seed=<value optimized out>, seed_size=<value optimized out>,
total_bytes=<value optimized out>, ret=0x7fff1951ad60
"\354\255Q\031\377\177") at gnutls_state.c:811
#12 0x00007fc5543b7d8a in _gnutls_PRF (session=<value optimized out>,
secret=<value optimized out>, secret_size=<value optimized out>,
label=<value optimized out>, label_size=<value optimized out>,
    seed=0x7fff1951b160
"K\222\352\274\311\367\273\213Y\314\356\252Lu-\325y\341\265\300,\t\311/\342\237\066\v\025\031l\373K\222\352\274/g\363\270\370\020\037[:\347b\037\033\223\322\070\257bɊ\271\340\f\342]\030\212=\001",
seed_size=<value optimized out>, total_bytes=48, ret=0x210c692) at
gnutls_state.c:926
#13 0x00007fc5543a55ff in generate_normal_master (session=0x210c670,
keep_premaster=0) at gnutls_kx.c:155
#14 0x00007fc5543b037b in _gnutls_connection_state_init (session=0x0)
at gnutls_constate.c:434
#15 0x00007fc5543a11c8 in _gnutls_send_handshake_final
(session=0x210c670, init=1) at gnutls_handshake.c:2472
#16 0x00007fc5543a13a5 in _gnutls_handshake_common (session=0x210c670)
at gnutls_handshake.c:2693
#17 0x00007fc5543a2a37 in gnutls_handshake (session=0x210c670) at
gnutls_handshake.c:2297
#18 0x00007fc554c9d40e in ?? () from /usr/lib/libldap_r-2.4.so.2
#19 0x00007fc554c9c1d2 in ?? () from /usr/lib/libldap_r-2.4.so.2
#20 0x00007fc554c9c433 in ldap_int_tls_start () from /usr/lib/libldap_r-2.4.so.2
#21 0x00007fc554c9c58e in ldap_start_tls_s () from /usr/lib/libldap_r-2.4.so.2
#22 0x00007fc554eb2b84 in ?? () from /lib/security/pam_ldap.so
#23 0x00007fc554eb4f37 in ?? () from /lib/security/pam_ldap.so
#24 0x00007fc554eb51a1 in ?? () from /lib/security/pam_ldap.so
#25 0x00007fc554eb5cc1 in pam_sm_acct_mgmt () from /lib/security/pam_ldap.so
#26 0x00007fc558f71bde in ?? () from /lib/libpam.so.0
#27 0x000000000048d7a0 in ?? ()
#28 0x0000000000477f56 in ?? ()
#29 0x000000000042cabb in ?? ()
#30 0x0000000000422ef7 in ?? ()
#31 0x0000000000414089 in ?? ()
#32 0x00007fc5578feabd in __libc_start_main () from /lib/libc.so.6
#33 0x0000000000411b29 in ?? ()
#34 0x00007fff1951cda8 in ?? ()
#35 0x000000000000001c in ?? ()
#36 0x0000000000000003 in ?? ()
#37 0x00007fff1951e6df in ?? ()
#38 0x00007fff1951e6f0 in ?? ()
#39 0x00007fff1951e6f3 in ?? ()
#40 0x0000000000000000 in ?? ()
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) n
Program not restarted.
(gdb) c
Continuing.
E: /dev/vg/schroot-lenny: Failed to stat file: Permission denied

Program exited normally.

--
Brian May <email address hidden>