Aiee :)
Hello!
I'm playing with the register_firewall kernel facilities
and everything works fine, but I got some weirdness, even if
I'm quite sure it's my fault.
I registered the firewall using this firewall_ops{}
struct firewall_ops dis_ops = {
NULL,
dis_dummy,
dis_dummy,
dis_output,
1,
AF_INET
};
dis_dummy simple returns FW_SKIP (so I can use ipchains
[fw->priority == 0] according to call_*_firewall sources).
dis_output after doing some basic checking, calls dis_dump.
void
dis_dump(struct *skb)
{
struct iphdr *ip = skb->nh.iph
printk(KERN_INFO "dst %d.%d.%d.%d\n", \
(ntohl(ip->daddr)>>24)&0xFF, \
(ntohl(ip->daddr)>>16)&0xFF, \
(ntohl(ip->daddr)>>8)&0xFF, \
(ntohl(ip->daddr))&0xFF);
printk(KERN_INFO "src %d.%d.%d.%d\n", \
(ntohl(ip->saddr)>>24)&0xFF, \
(ntohl(ip->saddr)>>16)&0xFF, \
(ntohl(ip->saddr)>>8)&0xFF, \
(ntohl(ip->saddr))&0xFF );
printk(KERN_INFO "skbuff dev %s\n", skb->dev->name);
return;
}
Everything runs fine (and I got the right dumping into the kernel
log), until I tried to ping flood (ping -f) an host, just
to get more traffic.
This is the Oops I got:
Apr 24 02:47:10 armageddon kernel: Unable to handle kernel NULL pointer dereference at
virtual address 00000000
current->tss.cr3 = 021f4000, %cr3 = 021f4000
*pde = 00000000
Oops: 0000
CPU: 0
EIP: 0010:[<c301a0bf>]
EFLAGS: 00010286
eax: 00000000 ebx: c2660490 ecx: c01e9c06 edx: c2468000
esi: c1986c20 edi: c21b9e10 ebp: c21b9d98 esp: c21b9d84
ds: 0018 es: 0018 ss: 0018
Process ping (pid: 478, process nr: 30, stackpage=c21b9000)
Stack: 00000014 0000001a 00000018 c2660490 c1986c20 c21b9db0 c301a140 c1986c20
c301a217 c301a2b8 00000002 00000000 c01469df c301a2b8 00000002 c27cccf4
c2660490 00000000 c21b9e10 c2660490 00000054 c1f0da40 c1c2eca0 c0157a17
Call Trace: [<c301a140>] [<c301a217>] [<c301a2b8>] [<c01469df>] [<c301a2b8>]
[<c0157a17>] [<c01630a1>]
[<c0162dd0>] [<c016894f>] [<c01688c0>] [<c0145376>] [<c01688c0>] [<c0145eac>]
[<c012d5aa>] [<c012d8f0>]
[<c018d74b>] [<c0109a42>] [<c01466d3>] [<c010899c>]
Code: 8b 00 50 68 d9 a1 01 c3 e8 78 89 0f fd 8d 65 f8 5b 5e 89 ec
zsh: 478 segmentation fault ping -f xxx.xxx.xxx.xxx
The module I'm using is registered @ (as /proc/ksyms said)
[<c301a2b8>] Where sits dis_ops (firewall_ops{})
Could anyone point me out on the right way plz ? Thx
bye bye
-- gg sullivan
--
Lorenzo Cavallaro `Gigi Sullivan' <[EMAIL PROTECTED]>
Until I loved, life had no beauty;
I did not know I lived until I had loved. (Theodor Korner)
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