[Bug 1014309] Re: mandos server segfault problem

[Jason Conti]

Looking at the stacktrace top when we crash on 'import gnutls.crypto':

#0  __pthread_mutex_lock (mutex=0x7ffff56f32c4) at pthread_mutex_lock.c:50
#1  0x00007ffff4f6c7bd in mutex_init (lock=0x7ffff520e228, just_check=1) at ath.c:132
#2  0x00007ffff4f6c91d in _gcry_ath_mutex_lock (lock=0x7ffff520e228) at ath.c:186
#3  0x00007ffff4f69b2d in _gcry_secmem_get_flags () at secmem.c:443
#4  0x00007ffff4f633e0 in _gcry_vcontrol (cmd=GCRYCTL_SUSPEND_SECMEM_WARN, arg_ptr=0x7ffffffef158) at global.c:378
#5  0x00007ffff4f600cd in gcry_control (cmd=GCRYCTL_SUSPEND_SECMEM_WARN) at visibility.c:78

We are crashing in gnutls/library/__init__.py. Because of bug 423252,
global_init() for libgcrypt is not being called on
GCRYCTL_SET_THREAD_CBS anymore, so when GCRYCTL_SUSPEND_SECMEM_WARN is
called, it tries to acquire the mutex, which has never been initialized.

As suggested in the comments for global_init(), adding:
libgnutls.gcry_check_version(None) just before the call to
GCRYCTL_SUSPEND_SECMEM_WARN will force a call to global_init(), and
there isn't a crash on 'import gnutls.crypto'.

** Patch added: "gcrypt-call-global-init.patch"
   https://bugs.launchpad.net/ubuntu/+source/libgcrypt11/+bug/1014309/+attachment/3231141/+files/gcrypt-call-global-init.patch

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https://bugs.launchpad.net/bugs/1014309

Title:
  mandos server segfault problem

Status in libgcrypt:
  New
Status in “libgcrypt11” package in Ubuntu:
  Confirmed

Bug description:
  at booting mandos server fails. Even a simple 'mandos --version' also fails with
  Segmentation fault (core dumped)

  syslog says e.g.:
  mandos[11084]: segfault at c ip 00427cb7 sp bfeec2b0 error 4 in libpthread-2.15.so[41f000+17000]

  this problem is reproducable on

  i386, 2 CPUs, Ubuntu precise, mandos version 1.4.0-1
  i386, 2 CPUs, Ubuntu precise, mandos manually upgraded to quantal package version 1.5.5-1
  amd64, 1 CPU, Ubuntu precise, mandos version 1.4.0-1
  amd64, 1 CPU, Ubuntu precise, mandos manually upgraded to quantal package version 1.5.5-1
  amd64, 1 CPU, Ubuntu precise, mandos manually downgraded to oneiric package version 1.3.0-1ubuntu1

  Mandos does not have this problem on machine with older Ubuntu version, e.g.
  amd64, 1 CPU, Ubuntu oneiric, mandos version 1.3.0-1ubuntu1
  amd64, 1 CPU, Ubuntu oneiric, mandos manually upgraded to precise package version 1.4.0-1
  amd64, 1 CPU, Ubuntu oneiric, mandos manually upgraded to quantal package version 1.5.5-1

  
  a 'python -v /usr/sbin/mandos' says:

  dlopen("/usr/lib/pymodules/python2.7/gnutls/library/_init.so", 2);
  import gnutls.library._init # dynamically loaded from /usr/lib/pymodules/python2.7/gnutls/library/_init.so
  Segmentation fault (core dumped)

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