Bug#195888: libc6: memory leak in libcrypt.so when dlopen/dlclose it

[Alexander Kogan <alexander@kogan.nnov.ru>]

Package: libc6
Version: 2.3.1-17
Severity: normal
Tags: upstream

When I dlopen() libcrypt.so, call crypt() and then dlclose() it,
memory leak occur. I think, crypt() use static pointer initialized on
first call to crypt() with malloc, but it isn't freed on _fini()

Here is a test code:

#include <dlfcn.h>

typedef const char* (*func)(const char*, const char*);

int main()
{
    for( int i=0; i<100; i++ ) {
        void * handle = dlopen( "libcrypt.so", RTLD_LAZY );
        func crypt = (func)dlsym( handle, "crypt" );
        crypt( "vasq", "$1$" );
        dlclose( handle );
    }
}


Here is a valgrind output for this code:
% c++ test.cc -ldl

% valgrind --leak-check=yes --show-reachable=yes ./a.out
==30343== Memcheck, a.k.a. Valgrind, a memory error detector for x86-linux.
==30343== Copyright (C) 2002, and GNU GPL'd, by Julian Seward.
==30343== Using valgrind-1.9.6, a program instrumentation system for x86-linux.
==30343== Copyright (C) 2000-2002, and GNU GPL'd, by Julian Seward.
==30343== Estimated CPU clock rate is 1003 MHz
==30343== For more details, rerun with: -v
==30343==
==30343==
==30343== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
==30343== malloc/free: in use at exit: 3400 bytes in 100 blocks.
==30343== malloc/free: 600 allocs, 500 frees, 73200 bytes allocated.
==30343== For counts of detected errors, rerun with: -v
==30343== searching for pointers to 100 not-freed blocks.
==30343== checked 4104836 bytes.
==30343==
==30343== 3400 bytes in 100 blocks are definitely lost in loss record 1 of 1
==30343==    at 0x4015D414: malloc (vg_clientfuncs.c:103)
==30343==    by 0x4015D904: realloc (vg_clientfuncs.c:268)
==30343==    by 0x4120526F: ???
==30343==    by 0x41204B47: ???
==30343==
==30343== LEAK SUMMARY:
==30343==    definitely lost: 3400 bytes in 100 blocks.
==30343==    possibly lost:   0 bytes in 0 blocks.
==30343==    still reachable: 0 bytes in 0 blocks.
==30343==         suppressed: 0 bytes in 0 blocks.
==30343==




-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux forward 2.4.20-forward #1 SMP ðÔÎ ñÎ× 24 16:19:36 MSK 2003 i686
Locale: LANG=ru_RU.KOI8-R, LC_CTYPE=ru_RU.KOI8-R

Versions of packages libc6 depends on:
ii  libdb1-compat                 2.1.3-7    The Berkeley database routines [gl

-- no debconf information