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Bug #16859 session_decode gives SEGV in PHP 4.2.0
Submitted: 2002-04-26 13:20 UTC Modified: 2002-09-25 08:31 UTC
Avg. Score:4.4 ± 0.9
Reproduced:8 of 9 (88.9%)
Same Version:2 (25.0%)
Same OS:0 (0.0%)
From: hope at internexo dot co dot cr Assigned: andrei (profile)
Status: Closed Package: Session related
PHP Version: 4.2.0, 4.3.0-dev OS: Solaris 2.6 (5.6)
Private report: No CVE-ID: None
 [2002-04-26 13:20 UTC] hope at internexo dot co dot cr
session_decode ($str) gives SEGV with PHP 4.2.0 and Apache 1.3.24.

Worked fine with PHP 4.1.2; I just built 4.2.0 with the same configure params and same Apache as I had with 4.1.2, and the same script gives the problem.

I have verified that the argument to session_decode ($str) is not null, etc.

Basically, my script is reading the $str out of several sess_* files and dumping the contents for each one.

There was a session_decode SEGV bug that was reported as fixed and closed in 4.0.1 pl2, so maybe the same bug is back.  

Thanks to all.


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 [2002-04-26 20:07 UTC]
To properly diagnose this bug, we need a backtrace to see what is
happening behind the scenes. To find out how to generate a backtrace,
please read

Once you have generated a backtrace, please submit it to this bug
report and change the status back to "Open".
 [2002-04-28 14:23 UTC] hope at internexo dot co dot cr
Backtrace (running in gdb with -X) is:
(gdb) bt
#0  0x8ed44 in php_set_session_var (name=0x3364f0 "ses_login", namelen=9, 
    state_val=0x328dd0, var_hash=0xefffcfb0) at session.c:290
#1  0x8f588 in ps_srlzr_decode_php (
    val=0x339128 "ses_login|s:8:\"theodore\";ses_id|s:19:\"PMwwKgoAADwAADKfkFU\";ses_timestamp_ultimo|i:1020014634;ses_timestamp_inicio|i:1020014634;ses_ip|s:9:\"\";ses_url|s:13:\"/contar.phtml\";ses_valor|i:1;", vallen=193)
    at session.c:441
#2  0x8f87c in php_session_decode (
    val=0x339128 "ses_login|s:8:\"theodore\";ses_id|s:19:\"PMwwKgoAADwAADKfkFU\";ses_timestamp_ultimo|i:1020014634;ses_timestamp_inicio|i:1020014634;ses_ip|s:9:\"\";ses_url|s:13:\"/contar.phtml\";ses_valor|i:1;", vallen=193)
    at session.c:490
#3  0x93454 in zif_session_decode (ht=1, return_value=0x3360d0, this_ptr=0x0, 
    return_value_used=0) at session.c:1339
#4  0x1a2080 in execute (op_array=0x323440) at ./zend_execute.c:1598
#5  0x169e48 in zend_execute_scripts (type=8, retval=0x0, file_count=3)
    at zend.c:810
#6  0x4e270 in php_execute_script (primary_file=0xeffff7f0) at main.c:1381
#7  0x17c1fc in apache_php_module_main (r=0x30a420, display_source_mode=0)
    at sapi_apache.c:90
#8  0x48b8c in send_php ()
#9  0x48bf8 in send_parsed_php ()
#10 0x1ad4e4 in ap_invoke_handler ()
#11 0x1bf494 in process_request_internal ()
#12 0x1bf4ec in ap_process_request ()
#13 0x1b7d84 in child_main ()
#14 0x1b7f38 in make_child ()
#15 0x1b8084 in startup_children ()
#16 0x1b866c in standalone_main ()
#17 0x1b8df4 in main ()

 [2002-04-29 12:06 UTC] hope at internexo dot co dot cr
As an explanation to the backtrace I posted:

The backslashes that appear before some of the double quotes in the backtrace are due to gdb.  The file that is read (and the string that's processed) do _not_ contain the backslash.

The variable "ses_login" is the first of the session variables that are stored as part of the session data.

The backtrace says that it's dying in session.c, line 290.  This is in function php_set_session_var(), at the point where it's trying to call zend_set_hash_symbol().

The PHP setting "register_globals" is set to "On" in both the local and master contexts.

The script that causes this error is calling session_decode without having called any kind of session_start or session_name beforehand.

(Again, this works as I expected it to in 4.1.2; the SEGV is in 4.2.0).
 [2002-05-25 12:14 UTC] thomas dot paulmichl at limu dot com
I can reproduce this bug on:
Linux 2.4.7-10
Apache 1.3.24
PHP 4.2.1

.... when using session_decode to decode session data strings read from /tmp/sess_* session files.
 [2002-06-09 22:28 UTC] chris-php at bolt dot cx
I can also reproduce this bug:

Linux 2.4.19-pre4 SMP
Apache 1.3.24
PHP 4.2.1
 [2002-06-09 22:31 UTC] chris-php at bolt dot cx
Forgot to mention, I have an example script including all session data which crashes it:
 [2002-06-09 22:56 UTC] chris-php at bolt dot cx
Recompiled with --enable-debug on FreeBSD 4.5, and I'm getting  a considerably different backtrace:

(gdb) bt
#0  0x8082108 in set_default_charset_by_name (cs_name=0x818d0cc "signature",
    flags=9) at charset.c:416
#1  0x8082879 in zm_info_pcre (zend_module=0x818200c) at php_pcre.c:88
#2  0x8082a25 in pcre_get_compiled_regex (
    regex=0x818200c "signature|s:8:\"Damn\\'..\";!daheader|!daHeaderRandom|!daIndexTop|!daMenuDeviations|daTaglines|s:2:\"no\";!daNewLimit|!daNewDevs|daBuddyList|N;daBuddyStatus|s:6:\"online\";!daNewDisplay|daSortBy|s:4:\"date\";d"...,
    extra=0x81b, preg_options=0x8151044) at php_pcre.c:164
#3  0x8084c72 in preg_replace_impl (ht=1, return_value=0x818d0ac,
    this_ptr=0x0, return_value_used=0, is_callable_replace=8 '\b')
    at php_pcre.c:1009
#4  0x80fdf48 in tsrm_strndup (s=0x817f88c "\002", length=2)
    at tsrm_virtual_cwd.c:161
#5  0x80e37b8 in zif_xml_parser_set_option (ht=8, return_value=0x0,
    this_ptr=0x3, return_value_used=0) at xml.c:1519
#6  0x8061242 in php_module_startup (sf=0xbfbffc10) at main.c:971
#7  0x805f180 in main (argc=3, argv=0xbfbffc78) at cgi_main.c:649
#8  0x805e54d in acos ()
 [2002-06-13 18:11 UTC] phpcoder at ihearditwas dot com
I can also reproduce a Segmentation Fault with session_decode() on:

RedHat 7.3
Apache 1.3.23
PHP 4.2.1
 [2002-08-19 16:11 UTC] dcottee at quicklaw dot com
session_decode() consistently causes a page fault using PHP 4.2.2 on three development PCs -- two with WIN98 SE and one with WINDOWS 2000
 [2002-08-19 16:22 UTC] dcottee at quicklaw dot com
I should have added that we are using Apache 1.3.20 and that session_decode() worked fine with PHP 4.1.2, but not with either PHP 4.2.1 or PHP 4.2.2.

 [2002-09-24 03:43 UTC]
reproduced with 4.3.0-dev

 [2002-09-24 06:17 UTC]
update versions.

 [2002-09-25 08:31 UTC]
This bug has been fixed in CVS.

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