RE: Segfault with "net ads password"

[James Willard]

Title: Message

Andrew,

 

It seems like you're right about the null pointer. Given the code block you mentioned, I rebuilt with --enable-krb5developer and ran gdb over it again with a breakpoint at net_ads_password() and displaying ads, ads->auth, and ads->auth.kdc_server. The following is the output from gdb at the line just before line 885 where kerberos_set_password() is called:

 

3: ads->auth = {realm = 0x0, password = 0x0, user_name = 0x0, kdc_server = 0x0, flags = 0, time_offset = 0}
2: ads->auth.kdc_server = 0x0
1: ads = (ADS_STRUCT *) 0x81af8e0

And of course, the call itself... null values and all... (usernames/passwords substituted)

 

(gdb)
kerberos_set_password (kpasswd_server=0x0, auth_principal=0x815c560 [EMAIL PROTECTED],
    auth_password=0x815c57c "Adminpass", target_principal=0xbffffbe5 [EMAIL PROTECTED],
    new_password=0x81535a0 "User", time_offset=0) at libads/krb5_setpw.c:470
470         return krb5_set_password(kpasswd_server, target_principal, new_password, time_offset);

Ok, this officially goes beyond my abilities... who maintains the "net ads" portion of Samba that could help me look into this further?

 

Thanks,

 

James Willard

[EMAIL PROTECTED]

 

-----Original Message-----
From: Esh, Andrew [mailto:[EMAIL PROTECTED]]
Sent: Friday, November 01, 2002 4:54 PM
To: 'James Willard'; [EMAIL PROTECTED]
Subject: RE: Segfault with "net ads password"
Importance: High

Looks like this bit of code is failing:

utils/net_ads.c, lines 877-886, function "net_ads_password"

    /* use the realm so we can eventually change passwords for users
    in realms other than default */
    if (!(ads = ads_init(realm, NULL, NULL))) return -1;

    asprintf(&prompt, "Enter new password for %s:", argv[0]);

    new_password = getpass(prompt);

    ret = kerberos_set_password(ads->auth.kdc_server, auth_principal,
                                auth_password, argv[0], new_password, ads->auth.time_offset);

the last line is reached with "ads->auth.kdc_server" as a bad (null?) pointer.  The "ads_init" function creates the ads structure and zeroes it. It doesn't appear to me as though "ads_init" initializes ads->auth, and I don't see where else it gets set.

-----Original Message-----
From: James Willard [mailto:[EMAIL PROTECTED]]
Sent: Friday, November 01, 2002 2:23 PM
To: [EMAIL PROTECTED]
Subject: RE: Segfault with "net ads password"

And as a follow-up to myself... The following is a backtrace from gdb:

Program received signal SIGSEGV, Segmentation fault.
0x080ec329 in interpret_addr ()
(gdb) bt
#0  0x080ec329 in interpret_addr ()
#1  0x080ec462 in interpret_addr2 ()
#2  0x080efbe0 in open_udp_socket ()
#3  0x0810f56c in krb5_set_password ()
#4  0x0810fdbf in kerberos_set_password ()
#5  0x0806b17c in net_ads_password ()
#6  0x08068690 in net_run_function ()
#7  0x0806b51c in net_ads ()
#8  0x08068690 in net_run_function ()
#9  0x080697d3 in main ()
#10 0x42017589 in __libc_start_main () from /lib/i686/libc.so.6

Thanks,

James Willard
[EMAIL PROTECTED]

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]] On Behalf Of James
Willard
Sent: Friday, November 01, 2002 2:12 PM
To: [EMAIL PROTECTED]
Subject: Segfault with "net ads password"

Hi,

I'm trying to troubleshoot a problem I've been having for the past
several weeks with "net ads password" attempting to change a users'
password. I'm using the Samba 3.0 CVS tree updated this morning (even
though there has been no difference in behavior in the past month or
so). I'm running:

net ads password [EMAIL PROTECTED] -U [EMAIL PROTECTED]%Password

I receive a prompt:

Enter new password for [EMAIL PROTECTED]:

I enter a password and then it segfaults. Below are excerpts from a
strace:

...
write(3, "kadmin", 6)                   = 6
write(3, "\0\0\0\10", 4)                = 4
write(3, "changepw", 8)                 = 8
...
write(3, "\0\0\0\0", 4)                 = 4
write(3, NULL, 0)                       = 0
fcntl64(3, F_SETLKW, {type=F_UNLCK, whence=SEEK_SET, start=0, len=0}) =
0
close(3)                                = 0
time(NULL)                              = 1036176903
gettimeofday({1036176903, 994633}, NULL) = 0 gettimeofday({1036176903,
995109}, NULL) = 0
--- SIGSEGV (Segmentation fault) ---
+++ killed by SIGSEGV +++

The operating system is RedHat Linux 7.3 on a PIII with krb5-1.2.5 and
openldap-2.1.4

What other information would be useful in tracking down this bug?

Thanks,

James Willard
[EMAIL PROTECTED]