Invalid credentials ( __validate_creds()) due to cred->magic =="DeaD" from sys_clone() (2.6.39 PREEMPT SMP SELinux kernel)

[Robert ÅwiÄcki]

Just some initial data:


=====================================================================
KDB
=====================================================================

<3>[49754.391126] CRED: Invalid credentials
<3>[49754.394811] CRED: At include/linux/cred.h:260
<3>[49754.399181] CRED: Specified credentials: ffff8801156c8b00
<3>[49754.404676] CRED: ->magic=44656144, put_addr=ffffffff81166dc5
<3>[49754.410430] CRED: ->usage=0, subscr=0
<3>[49754.414102] CRED: ->*uid = { 65534,65534,65534,65534 }
<3>[49754.419250] CRED: ->*gid = { 65534,65534,65534,65534 }
<3>[49754.424397] CRED: ->security is ffff8801113069c0
<3>[49754.429021] CRED: ->security {1, 1}

[1]kdb> bt
Stack traceback for pid 16009
0xffff880115819770    16009     8897  1    1   R  0xffff880115819bf0 *iknowthis2
<c> ffff88012bc43e00<c> 0000000000000000<c> ffff880100000104<c>
ffffffff8267436f<c>
<c> ffffffff81b611cd<c> ffff8801156c8b00<c> ffff88012bc43e40<c>
ffffffff81166d8e<c>
<c> ffff8801156c8b00<c> ffff880121e13540<c> ffff88012bc43e60<c>
ffffffff81166db3<c>
Call Trace:
 <IRQ>  [<ffffffff81b611cd>] ? wq_free_rcu+0x12/0x14
 [<ffffffff81166d8e>] ? __validate_creds.clone.9+0x2d/0x32
 [<ffffffff81166db3>] ? file_free_rcu+0x20/0x46
 [<ffffffff810eeb82>] ? __rcu_process_callbacks+0x18d/0x2af
 [<ffffffff810eed24>] ? rcu_process_callbacks+0x80/0x87
 [<ffffffff8109c013>] ? __do_softirq+0xeb/0x1cc
 [<ffffffff81044977>] ? native_sched_clock+0x35/0x37
 [<ffffffff810b67dd>] ? sched_clock_local+0x12/0x75
 [<ffffffff81edbd9c>] ? call_softirq+0x1c/0x30
 [<ffffffff81040510>] ? do_softirq+0x4b/0x9f
 [<ffffffff8109c380>] ? irq_exit+0x5f/0xb6
 [<ffffffff81edc6d1>] ? smp_apic_timer_interrupt+0x7d/0x8b
 [<ffffffff81edb553>] ? apic_timer_interrupt+0x13/0x20
 <EOI>  [<ffffffff81093f75>] ? dup_mm+0x1f2/0x468
 [<ffffffff81151cdb>] ? arch_local_irq_restore+0x6/0xd
 [<ffffffff81154ceb>] ? __slab_alloc.clone.36+0xf0/0x38b
 [<ffffffff81093f75>] ? dup_mm+0x1f2/0x468
 [<ffffffff81155143>] ? kmem_cache_alloc+0x4a/0xe7
 [<ffffffff8135b0ce>] ? selinux_vm_enough_memory+0x48/0x4d
 [<ffffffff81093f75>] ? dup_mm+0x1f2/0x468
 [<ffffffff81094c56>] ? copy_process+0xa3e/0x1230
 [<ffffffff81095592>] ? do_fork+0x10f/0x29d
 [<ffffffff813d8dba>] ? trace_hardirqs_off_thunk+0x3a/0x6c
 [<ffffffff8107e5b9>] ? sys32_clone+0x26/0x28
 [<ffffffff81edc585>] ? ia32_ptregs_common+0x25/0x4b

kdb>   summary

sysname    Linux
release    2.6.39
version    #3 SMP PREEMPT Fri May 27 15:27:03 CEST 2011
machine    x86_64
nodename   ise-test
domainname (none)
ccversion  CCVERSION
date       2011-05-28 03:20:03 tz_minuteswest -120
uptime     13:49
load avg   19.38 20.17 22.96

MemTotal:         993059 kB
MemFree:          458493 kB
Buffers:           23981 kB


=====================================================================
KGDB
=====================================================================

(gdb) bt
#0  __invalid_creds (cred=0xffff8801156c8b00, file=<value optimized
out>, line=<value optimized out>)
    at kernel/cred.c:812
#1  0xffffffff81166d8e in __validate_creds (cred=0xffff8801156c8b00, line=260,
    file=0xffffffff8267436f "include/linux/cred.h") at include/linux/cred.h:186
#2  0xffffffff81166db3 in put_cred (head=<value optimized out>) at
include/linux/cred.h:260
#3  file_free_rcu (head=<value optimized out>) at fs/file_table.c:49
#4  0xffffffff810eeb82 in rcu_do_batch (rsp=0xffffffff82a2f500,
rdp=0xffff88012bc502f0) at kernel/rcutree.c:1146
#5  __rcu_process_callbacks (rsp=0xffffffff82a2f500,
rdp=0xffff88012bc502f0) at kernel/rcutree.c:1386
#6  0xffffffff810eed24 in rcu_preempt_process_callbacks (unused=<value
optimized out>) at kernel/rcutree_plugin.h:544
#7  rcu_process_callbacks (unused=<value optimized out>) at
kernel/rcutree.c:1404
#8  0xffffffff8109c013 in __do_softirq () at kernel/softirq.c:238
#9  0xffffffff81edbd9c in ?? () at arch/x86/kernel/entry_64.S:1210
#10 0xffffffff81040510 in do_softirq () at arch/x86/kernel/irq_64.c:80
#11 0xffffffff8109c380 in invoke_softirq () at kernel/softirq.c:325
#12 irq_exit () at kernel/softirq.c:340
#13 0xffffffff81edc6d1 in smp_apic_timer_interrupt (regs=<value
optimized out>) at arch/x86/kernel/apic/apic.c:861
#14 <signal handler called>
#15 0x00cf9b000000ffff in __brk_reservation_fn_dmi_alloc__ ()
Cannot access memory at address 0xcffb000000ffff

Cannot access memory at address 0xcffb000000ffff
(gdb) up
#1  0xffffffff81166d8e in __validate_creds (cred=0xffff8801156c8b00, line=260,
    file=0xffffffff8267436f "include/linux/cred.h") at include/linux/cred.h:186
186			__invalid_creds(cred, file, line);
(gdb) p *cred
$1 = {usage = {counter = 0}, subscribers = {counter = 0}, put_addr =
0xffffffff81166dc5, magic = 1147494724,
  uid = 65534, gid = 65534, suid = 65534, sgid = 65534, euid = 65534,
egid = 65534, fsuid = 65534, fsgid = 65534,
  securebits = 0, cap_inheritable = {cap = {0, 0}}, cap_permitted =
{cap = {0, 0}}, cap_effective = {cap = {0, 0}},
  cap_bset = {cap = {4294967295, 4294967295}}, jit_keyring = 0 '\000',
thread_keyring = 0x0, request_key_auth = 0x0,
  tgcred = 0xffff88011492b088, security = 0xffff8801113069c0, user =
0xffff880121c4b000, user_ns = 0xffffffff82a21a80,
  group_info = 0xffff880104cec420, rcu = {next = 0x0, func =
0xffffffff810b6c97 <put_cred_rcu>}}

(gdb) p (char[4])cred->magic
$8 = "DaeD"

-- 
Robert ÅwiÄcki
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/