Fwd: [Bug 1754] New: IPsec crash when sending 1st encrypted packet in tunnel mode

Hi !

Found on LKML but not on netdev (perhaps Martin forgot to Cc). Might be of
interest to people here.

Cheers,
Willy

On Sat, Dec 27, 2003 at 08:38:52AM -0800, Martin J. Bligh wrote:

http://bugme.osdl.org/show_bug.cgi?id=1754

           Summary: IPsec crash when sending 1st encrypted packet in tunnel
                    mode
    Kernel Version: 2.6.0
            Status: NEW
          Severity: high
             Owner: acme@conectiva.com.br
         Submitter: rakon@hck.sk


Distribution:lfs v.5.0
Hardware Environment: desknote iBuddie ()
Software Environment: lfs v.5.0 + ipsec-tools-0.2.2 and others...

Problem Description:
After creating tunnel between two hosts connected with crossed twisted pair
cable, I got a kernel crash after successfull IPsec SA establishment
(kernel-2.4.23 + Freeswan-2.04 with x509 patch <==> kernel-2.6.0 +
ipsec-tools-0.2.2) when sending 1st encrypted packet (simple ping). I see this
screen when crash occurs:

KERNEL: assertion (x->km.state == XFRM_STATE_DEAD) failed at
net/xfrm/xfrm_state.c (193)
------------[ cut here ]------------
kernel BUG at net/xfrm/xfrm_state.c:54!
invalid operand: 0000 [#1]
CPU:    0
EIP:    0060:[<c0341626>]    Not tainted
EFLAGS: 00010202
EIP is at xfrm_state_gc_destroy+0x16/0xd0
eax: 00000001   ebx: ca8c0000   ecx: cbc8c000   edx: ca8c0120
esi: cbc8df6c   edi: c04b8f20   ebp: cbc8c000   esp: cbc8df60
ds: 007b   es: 007b   ss:0068
Process events/0 (pid: 3, threadinfo=cbc8c000 task=cbfa8c80)
Stack: cbc8df6c c0341756 ca8c0000 ca8c0000 ca8c0000 cbfedc60 c04b8f24 c012b51b
       00000000 cbfedc78 cbfedc70 00000000 c03416e0 cbfedc68 cbc8c000 cbfedc60
       00000001 00000000 c0119e80 00010000 00000000 c03b6380 c11eff1c c010ab96
Call Trace:
 [<c0341756>] xfrm_state_gc_task+0x76/0x90
 [<c012b51b>] worker_thread+0x1ab/0x2a0
 [<c03416e0>] xfrm_state_gc_task+0x0/0x90
 [<c0119e80>] default_wake_function+0x0/0x20
 [<c010ab96>] ret_from_fork+0x6/0x20
 [<c0119e80>] default_wake_function+0x0/0x20
 [<c012b370>] worker_thread+0x0/0x2a0
 [<c0108d65>] kernel_thread_helper+0x5/0x10

Code: 0f 0b 36 00 c1 ed 3a c0 8b 83 d0 00 00 00 85 c0 0f 85 94 00

Steps to reproduce:
* I'll use xml tags (name of file) as start/end of file marks

1) run this script:
<policy>
# ! /usr/sbin/setkey -f
flush;
spdflush;

spdadd 10.0.0.22/32 0.0.0.0/0 any
       -P out ipsec esp/tunnel/10.0.0.1-10.0.0.22/require;
spdadd 0.0.0.0/0 10.0.0.22/32 any
       -P out ipsec esp/tunnel/10.0.0.1-10.0.0.22/require;
</policy>

2) run "racoon -F -f racoon.conf"
where racoon.conf contains:

<racoon.conf>
path certificate "/etc/ipsec.d";
remote 10.0.0.1 {
  exchange_mode main;
  certificate_type x509 "mycert.pem" "mycert-key.pem"
  verify_cert on;
  my_identifier asn1dn;
  peers_identifier asn1dn;
  proposal {
    encryption_algorithm 3des;
    hash_algorithm md5;
    authentication_method rsasig;
    dh_group 2;
  }
}

sainfo anonymous {
  pfs_group 2;
  encryption_algorithm 3des;
  authentication_algorithm hmac_md5;
  compression_algorithm deflate;
}
</racoon.conf>

3) run "ping 10.0.0.1" and see the crash screen

Reason of crash:

I've found the problem in policies script (see point 1), where is:

spdadd 10.0.0.2/32 0.0.0.0/0 any
       -P out ipsec esp/tunnel/10.0.0.1-10.0.0.2/require;
spdadd 0.0.0.0/0 10.0.0.2/32 any
       -P out ipsec esp/tunnel/10.0.0.1-10.0.0.2/require;

instead of:

spdadd 10.0.0.2/32 0.0.0.0/0 any
       -P out ipsec esp/tunnel/10.0.0.2-10.0.0.1/require;
spdadd 0.0.0.0/0 10.0.0.2/32 any
       -P out ipsec esp/tunnel/10.0.0.1-10.0.0.2/require;

Note the tunnel specification in the 10.0.0.2/32 -> 0.0.0.0/0 rule. When using
this second form, kernel doesn't crash and everything (at least pings and ssh to
peer) works as expected.
I guess this is a problem of kernel, since kernel shouldn't crash under any
circumstances. But this could be a problem of ipsec-tools-0.2.2 as well since it
allows incorrect input from user - however, the latter doesn't have to be true
under certain conditions.

Regards.

PS: If more feedback is needed, send me an email.

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