[Openswan Users] openswan 2.6.33 rmmod ipsec cause kernel oops of null pointer
David McCullough
david_mccullough at mcafee.com
Wed Mar 30 23:02:04 EDT 2011
Jivin Zhiping Liu lays it down ...
> produced by following:
Thanks for that, we are doing a double ipsec_dev_put which I think is the
problem. try the attached patch and see how that goes.
Cheers,
Davidm
> 1.kernel version: latest stable 2.6.38.1
>
> PL-SMS ~ # uname -r
> 2.6.38.1
> PL-SMS ~ #
>
> 2.ipsec config file:
>
> PL-SMS openswan-2.6.33 # cat /etc/ipsec.conf
> # /etc/ipsec.conf - Openswan IPsec configuration file
>
> # This file: /usr/local/share/doc/openswan/ipsec.conf-sample
> #
> # Manual: ipsec.conf.5
>
>
> version 2.0 # conforms to second version of ipsec.conf specification
>
> # basic configuration
> config setup
> # Do not set debug options to debug configuration issues!
> # plutodebug / klipsdebug = "all", "none" or a combation from below:
> # "raw crypt parsing emitting control klips pfkey natt x509 dpd private"
> # eg:
> # plutodebug="control parsing"
> #
> # enable to get logs per-peer
> # plutoopts="--perpeerlog"
> #
> # Again: only enable plutodebug or klipsdebug when asked by a developer
> #
> # NAT-TRAVERSAL support, see README.NAT-Traversal
> nat_traversal=yes
> # exclude networks used on server side by adding %v4:!a.b.c.0/24
> virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12
> # OE is now off by default. Uncomment and change to on, to enable.
> oe=off
> # which IPsec stack to use. auto will try netkey, then klips then mast
> protostack=mast
>
>
> # Add connections here
>
> # sample VPN connection
> # for more examples, see /etc/ipsec.d/examples/
> #conn sample
> # # Left security gateway, subnet behind it, nexthop toward right.
> # left=10.0.0.1
> # leftsubnet=172.16.0.0/24
> # leftnexthop=10.22.33.44
> # # Right security gateway, subnet behind it, nexthop toward left.
> # right=10.12.12.1
> # rightsubnet=192.168.0.0/24
> # rightnexthop=10.101.102.103
> # # To authorize this connection, but not actually start it,
> # # at startup, uncomment this.
> # #auto=add
>
> PL-SMS openswan-2.6.33 #
>
> 3.how to produce kernel oops
>
>
> PL-SMS ~ # modprobe ipsec
> PL-SMS ~ # rmmod ipsec
> Killed
> PL-SMS ~ # lsmod
> Module Size Used by
> ipsec 311608 0
> PL-SMS ~ #
>
> 4.kernel dmesg shows:
>
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<f8101a59>] ipsec_mast_cleanup_devices+0x2f/0x4a [ipsec]
> *pde = 00000000
> Oops: 0002 [#1]
> last sysfs file: /sys/devices/virtual/net/ipsec0/address
> Modules linked in: ipsec(-)
>
> Pid: 3387, comm: rmmod Not tainted 2.6.38.1 #5 System manufacturer System Product Name/M2A-VM
> EIP: 0060:[<f8101a59>] EFLAGS: 00010246 CPU: 0
> EIP is at ipsec_mast_cleanup_devices+0x2f/0x4a [ipsec]
> EAX: 00000000 EBX: 00000000 ECX: f5b1bef8 EDX: 00000001
> ESI: 00000000 EDI: 00000880 EBP: f5b1bf2c ESP: f5b1bf28
> DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
> Process rmmod (pid: 3387, ti=f5b1a000 task=f5f14c80 task.ti=f5b1a000)
> Stack:
> f813aa40 f5b1bf4c f80f4013 f5b1bf54 f5b1bf4c c103aa8b f813aa40 00000000
> 00000880 f5b1bfac c103a479 65737069 00000063 f5b2edc0 f5b1bf70 c10599db
> f5b2edc0 f5eb9380 f5b1bf9c c105a315 ffffffff b77aa000 b77ab000 f5b2ecc4
> Call Trace:
> [<f80f4013>] cleanup_module+0x13/0x12a [ipsec]
> [<c103aa8b>] ? __try_stop_module+0xf/0x4c
> [<c103a479>] sys_delete_module+0x17c/0x1cf
> [<c10599db>] ? remove_vma+0x41/0x47
> [<c105a315>] ? do_munmap+0x1de/0x20c
> [<c1002710>] sysenter_do_call+0x12/0x26
> Code: 31 db eb 35 8b 14 9d 60 c0 13 f8 85 d2 74 29 8b 82 d8 01 00 00 ff 08 89 d0 e8 c7 57 18 c9 8b 04 9d 60 c0 13 f8 8b 80 d8 01 00 00 <ff> 08 c7 04 9d 60 c0 13 f8 00 00 00 00 43 3b 1d e8 8c 13 f8 7e
> EIP: [<f8101a59>] ipsec_mast_cleanup_devices+0x2f/0x4a [ipsec] SS:ESP 0068:f5b1bf28
> CR2: 0000000000000000
> ---[ end trace 01ae9d869f653d55 ]---
> PL-SMS ~ #
>
> thanks for you reply!
>
> 2011/3/31 David McCullough <david_mccullough at mcafee.com>
>
>
> Jivin Zhiping Liu lays it down ...
>
> > Hi all:
> >
> > I don't know if anyone have found out this before,but it's obviously a bug in file: linux/net/ipsec/ipsec_mast.c
> >
> >
> > 1085 int
> > 1086 ipsec_mast_init_devices(void)
> > 1087 {
> > 1088 /*
> > 1089 * mast0 is used for transport mode stuff, and generally is
> > 1090 * the default unless the user decides to create more.
> > 1091 */
> > 1092 ipsec_mast_createnum(0);
> > 1093
> > 1094 return 0;
> > 1095 }
> >
> > line 1092 set mast device num (mastdevices_max) to 0.
> >
> > if we do a rmmod ipsec now ,in ipsec_mast_cleanup_devices
> >
> > 1098 int
> > 1099 ipsec_mast_cleanup_devices(void)
> > 1100 {
> > 1101 int error = 0;
> > 1102 int i;
> > 1103 struct net_device *dev_mast;
> > 1104
> > 1105 for(i = 0; i <= mastdevices_max; i++) {
> > 1106 if(mastdevices[i]!=NULL) {
> > 1107 dev_mast = mastdevices[i];
> > 1108 //lzp add
> > 1109 if (!dev_mast)
> > 1110 printk(KERN_WARNING "dev_mast null");
> > 1111 ipsec_dev_put(dev_mast);
> > 1112 unregister_netdev(dev_mast);
> > 1113 #ifndef alloc_netdev
> > 1114 kfree(dev_mast->priv);
> > 1115 dev_mast->priv=NULL;
> > 1116 #endif
> > 1117 ipsec_dev_put(mastdevices[i]);
> > 1118 mastdevices[i]=NULL;
> > 1119 }
> > 1120 }
> > 1121 return error;
> > 1122 }
> >
> > we will clean up mastdevices[0],which is not initialize yet.
>
>
> It will be initialised because ipsec_mast_createnum initialises it.
>
> The code at 1106 checks if it's non-NULL before cleaning it up, so this is
> safe also as mastdevices will be initialised to all 0's, and we always set it
> back to NULL when we clean up.
>
>
> > change to this fix the problem
> > 1085 int
> > 1086 ipsec_mast_init_devices(void)
> > 1087 {
> > 1088 /*
> > 1089 * mast0 is used for transport mode stuff, and generally is
> > 1090 * the default unless the user decides to create more.
> > 1091 */
> > 1092 ipsec_mast_createnum(-1);
> > 1093
> > 1094 return 0;
> > 1095 }
>
>
> This will almost certainly cause a problem as we will index into mastdevices
> with -1 which is bad.
>
> Do you have a kernel oops that points to a problem here? That might helps
> because as it stands I don't see a problem with that particular code path,
>
> Cheers,
> Davidm
>
>
> --
> David McCullough, david_mccullough at mcafee.com, Ph:+61 734352815
> McAfee - SnapGear http://www.mcafee.com http://www.uCdot.org
>
>
>
>
>
> --
>
>
>
--
David McCullough, david_mccullough at mcafee.com, Ph:+61 734352815
McAfee - SnapGear http://www.mcafee.com http://www.uCdot.org
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