ID: 9801
Updated by: derick
Status: Analyzed
Bug Type: mcrypt related
Operating system: 
PHP Version: 4.0 Latest CVS (16/03/2001)
Assigned To: derick


looks all ok. I'll check it out, and apply the patch (if ok) so that it will be fixed 
in PHP 4.0.6


Previous Comments:

[2001-05-17 16:16:59] [EMAIL PROTECTED]
I think I've found the problem (and the solution).

Let's look at some functions found in mcrypt first...

File: mcrypt_modules.c

int mcrypt_module_close(MCRYPT td)


        td->algorithm_handle = NULL;
        td->mode_handle = NULL;

        td->m_encrypt = NULL;
        td->a_encrypt = NULL;
        td->a_decrypt = NULL;
        td->m_decrypt = NULL;

        return 0;

File: mcrypt.c

int mcrypt_generic_end(const MCRYPT td)
        return 0;

The crash occurs when the call free(td) is made in mcrypt_module_close(MCRYPT td)

Notice that mcrypt_generic_end(const MCRYPT td) calls mcrypt_module_close(MCRYPT td) 
in the end.

Let's look at the mcrypt.c file from PHP (NOT the same one as above). It has a 
function called

php_mcrypt_do_crypt(char* cipher, zval **key, zval **data, char *mode, zval **iv, int 
argc, int dencrypt, zval* return_value)

At the end of the function, we find the following:

/* freeing vars */
        mcrypt_generic_end (td);
        if (key_s != NULL)
                efree (key_s);
        if (iv_s != NULL)
                efree (iv_s);
        efree (data_s);
        mcrypt_module_close (td);

The crash occurs when the final mcrypt_module_close is called.

The reason is that the call to mcrypt_generic_end (td) also calls 
mcrypt_module_close(td) that again calls free (td). When we later call 
mcrypt_module_close (td) we try to free td again, and that sometimes gives us a 
segmentation fault.

The solution is simply to delete the last line in the php_mcrypt_do_crypt function 
(mcrypt_module_close (td);) found in mcrypt.c. This is ok, since we have already freed 
td in the call to mcrypt_generic_end (td) a few lines above.

That solved the problems for me. Finally no more crashes :)


[2001-04-10 13:58:16] [EMAIL PROTECTED]
Crashes for me too, possibly a bug in mcrypt it self. Trying more things...


[2001-04-10 13:01:24] [EMAIL PROTECTED]
Actually, the script only seems to dump core if I do:

    echo bin2hex($output);

after the encryption.  Just a simple:

    echo $output;

seems to work just fine (i.e. it outputs stuff).

- Colin


[2001-04-10 12:59:24] [EMAIL PROTECTED]
This happens for me too with today's CVS and the latest CVS of mcrypt.

Backtrace says:

#0  0x402c89bc in chunk_free (ar_ptr=0x40369680, p=0x81f7f00) at malloc.c:3152
3152    malloc.c: No such file or directory.
(gdb) bt
#0  0x402c89bc in chunk_free (ar_ptr=0x40369680, p=0x81f7f00) at malloc.c:3152
#1  0x402c8828 in __libc_free (mem=0x81f7f08) at malloc.c:3054
#2  0x400a650d in mcrypt_module_close (td=0x81f7f08) at mcrypt_modules.c:48
#3  0x807c1e7 in php_mcrypt_do_crypt (cipher=0x81f7e94 "rijndael-256", key=0x81f2118, 
    mode=0x818174c "cbc", iv=0x81f2124, argc=5, dencrypt=0, return_value=0x81f7ef4) at 
#4  0x807c576 in php_if_mcrypt_encrypt (ht=5, return_value=0x81f7ef4, this_ptr=0x0, 
    at mcrypt.c:1334
#5  0x81228e6 in execute (op_array=0x81f37dc) at ./zend_execute.c:1494
#6  0x80f3fcd in zend_execute_scripts (type=8, file_count=3) at zend.c:743
#7  0x8069c8f in php_execute_script (primary_file=0xbffffa60) at main.c:1196
#8  0x8067fa4 in main (argc=2, argv=0xbffffb04) at cgi_main.c:731
#9  0x4026ab5c in __libc_start_main (main=0x8067830 <main>, argc=2, ubp_av=0xbffffb04, 
init=0x8064b8c <_init>, 
    fini=0x81362ec <_fini>, rtld_fini=0x4000d634 <_dl_fini>, stack_end=0xbffffafc)
    at ../sysdeps/generic/libc-start.c:129

Assigning it to the expert ... :)


[2001-03-16 20:58:56] [EMAIL PROTECTED]
When I run .php files under Apache (1.3.19) PHP sometimes crash. I can run the same 
file several times, and only sometimes is crashes.

This is what is recorded in the apache log (a lot of them):

[Fri Mar  9 19:24:51 2001] [notice] child pid 22845 exit signal Segmentation fault 

The following code can reproduce the crash:

$input = "Teststring";
$key = "gQ8V(|!kQlmJ8*~/HajI~lNM.-HzJqy";
$iv = "w81kaMfJq(1lcJaQ+m BsjedLq!230?";
$output = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $input, MCRYPT_MODE_CBC, $iv);

The configure line is: --enable-track-vars --with-mysql=/usr/local/mysql --with-mhash 


The remainder of the comments for this report are too long.  To view the rest of the 
comments, please view the bug report online.

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