Package: kernel-image-2.6.8-11-amd64-k8-smp
Severity: important
While using the ipt_recent kernel module to stop SSH bruteforce attacks,
the kernel panics on a 32-bitism. This crash can occur at any time.
-------------------8<-----------------------
Unable to handle kernel paging request at ffffff00005e3000 RIP:
<ffffffff801c8a20>{__memset+32}
PML4 3e8063 PGD 1ff9067 PMD 365ae067 PTE 0
Oops: 0002 [1] SMP
CPU 0
Modules linked in: ipv6 ipt_REJECT ipt_LOG ipt_state ipt_pkttype ipt_recent
ipt_iprange ipt
Pid: 0, comm: swapper Not tainted 2.6.8-11-amd64-k8-smp
RIP: 0010:[<ffffffff801c8a20>] <ffffffff801c8a20>{__memset+32}
RSP: 0018:ffffffff80392450 EFLAGS: 00010216
RAX: 0000000000000000 RBX: 00000000000007f8 RCX: 0000000000000006
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffff00005e3000
RBP: ffffff00005dd000 R08: 0000000000000000 R09: ffffff00005e2fe0
R10: ffffff00005e4000 R11: ffffff00005e6000 R12: 0000000000000059
R13: ffffff00005df000 R14: 000000008b905486 R15: 0000000000000059
FS: 0000002a958ab640(0000) GS:ffffffff803e2e40(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: ffffff00005e3000 CR3: 0000000000101000 CR4: 00000000000006e0
Process swapper (pid: 0, threadinfo ffffffff803e6000, task ffffffff802ef6c0)
Stack: ffffffffa01f38f0 ffffffffa01a4f1d ffffff00005e6000 ffffff00005e4000
0000000000000206 ffffffff7ec35980 40ffff0000000059 ffffff00005f2418
00000001005be582 00000000803925d0
Call Trace:<IRQ> <ffffffffa01f38f0>{:ipt_recent:match+1728}
<ffffffffa01a4f1d>{:ip_conntra
<ffffffffa019c28d>{:ip_tables:ipt_do_table+605}
<ffffffff8024e91a>{nf_iterate+90}
<ffffffff8025ed50>{ip_local_deliver_finish+0}
<ffffffff8024ed87>{nf_hook_slow+135}
<ffffffff8025ed50>{ip_local_deliver_finish+0}
<ffffffff8025f160>{ip_local_deliver+5
<ffffffff8025f3b3>{ip_rcv_finish+579}
<ffffffff8025f170>{ip_rcv_finish+0}
<ffffffff8025f170>{ip_rcv_finish+0} <ffffffff8024edca>{nf_hook_slow+202}
<ffffffff8025f170>{ip_rcv_finish+0} <ffffffff8025f89d>{ip_rcv+1165}
<ffffffff80245f1d>{netif_receive_skb+461}
<ffffffff8010fbd5>{ret_from_intr+0}
<ffffffffa00f73b9>{:tg3:tg3_poll+1705}
<ffffffff80246114>{net_rx_action+132}
<ffffffff801391e3>{__do_softirq+83} <ffffffff80139275>{do_softirq+53}
<ffffffff801125a1>{do_IRQ+321} <ffffffff8010d980>{default_idle+0}
<ffffffff8010fbd5>{ret_from_intr+0} <EOI>
<ffffffff802a5399>{thread_return+41}
<ffffffff8010d9a0>{default_idle+32} <ffffffff8010da2a>{cpu_idle+26}
<ffffffff803e96fb>{start_kernel+507} <ffffffff803e9203>{_sinittext+515}
Code: f3 48 ab 44 89 c1 f3 aa 4c 89 c8 c3 66 66 66 90 ff c9 48 89
RIP <ffffffff801c8a20>{__memset+32} RSP <ffffffff80392450>
CR2: ffffff00005e3000
<0>Kernel panic: Aiee, killing interrupt handler!
In interrupt handler - not syncing
<0>Rebooting in 30 seconds..
-------------------8<-----------------------
The blog entry below details the bug and supplies the patch:
http://blog.blackdown.de/2005/05/09/fixing-the-ipt_recent-netfilter-module/
http://blog.blackdown.de/static/kernel/ipt_recent-fix.patch
Here is the patch for 2.6:
-------------------8<-----------------------
Fixing the ipt_recent Netfilter Module
(cf.
http://blog.blackdown.de/2005/05/09/fixing-the-ipt_recent-netfilter-module/)
I've had some ipt_recent rules acting strangely after an uptime of
about 25 days. The problem is reproducible in the 5 minutes before
the first jiffies roll-over right after booting too.
The problem is caused by the jiffies comparision which doesn't work
like intended if one of the last hit was more than LONG_MAX seconds
again or if the table of last hits contains empty slots and jiffies
is > LONG_MAX.
This patch fixes the problem by using get_seconds() instead of
jiffies. It also fixes some 64-bit issues.
Signed-off-by: Juergen Kreileder <[EMAIL PROTECTED]>
diff --exclude=arch --exclude-from=Documentation/dontdiff -ur
../linux-2.6.12-rc3-mm3/include/linux/netfilter_ipv4/ipt_recent.h
./include/linux/netfilter_ipv4/ipt_recent.h
--- ../linux-2.6.12-rc3-mm3/include/linux/netfilter_ipv4/ipt_recent.h
2005-03-02 08:38:10.000000000 +0100
+++ ./include/linux/netfilter_ipv4/ipt_recent.h 2005-05-09 14:50:40.000000000
+0200
@@ -2,7 +2,7 @@
#define _IPT_RECENT_H
#define RECENT_NAME "ipt_recent"
-#define RECENT_VER "v0.3.1"
+#define RECENT_VER "v0.3.2"
#define IPT_RECENT_CHECK 1
#define IPT_RECENT_SET 2
diff --exclude=arch --exclude-from=Documentation/dontdiff -ur
../linux-2.6.12-rc3-mm3/net/ipv4/netfilter/ipt_recent.c
./net/ipv4/netfilter/ipt_recent.c
--- ../linux-2.6.12-rc3-mm3/net/ipv4/netfilter/ipt_recent.c 2005-03-02
08:37:48.000000000 +0100
+++ ./net/ipv4/netfilter/ipt_recent.c 2005-05-09 15:06:58.000000000 +0200
@@ -15,6 +15,7 @@
#include <linux/ctype.h>
#include <linux/ip.h>
#include <linux/vmalloc.h>
+#include <linux/time.h>
#include <linux/moduleparam.h>
#include <linux/netfilter_ipv4/ip_tables.h>
@@ -64,7 +65,7 @@
struct time_info_list {
u_int32_t position;
- u_int32_t time;
+ unsigned long time;
};
/* Structure of our linked list of tables of recent lists. */
@@ -223,7 +224,7 @@
curr_table->table[count].last_seen = 0;
curr_table->table[count].addr = 0;
curr_table->table[count].ttl = 0;
-
memset(curr_table->table[count].last_pkts,0,ip_pkt_list_tot*sizeof(u_int32_t));
+
memset(curr_table->table[count].last_pkts,0,ip_pkt_list_tot*sizeof(unsigned
long));
curr_table->table[count].oldest_pkt = 0;
curr_table->table[count].time_pos = 0;
curr_table->time_info[count].position = count;
@@ -418,8 +419,8 @@
if(debug) printk(KERN_INFO RECENT_NAME ": match(): checking table,
addr: %u, ttl: %u, orig_ttl: %u\n",addr,ttl,skb->nh.iph->ttl);
#endif
- /* Get jiffies now in case they changed while we were waiting for a
lock */
- now = jiffies;
+ /* Get time now in case it changed while we were waiting for a lock */
+ now = get_seconds();
hash_table = curr_table->hash_table;
time_info = curr_table->time_info;
@@ -502,7 +503,7 @@
location = time_info[curr_table->time_pos].position;
hash_table[r_list[location].hash_entry] = -1;
hash_table[hash_result] = location;
-
memset(r_list[location].last_pkts,0,ip_pkt_list_tot*sizeof(u_int32_t));
+
memset(r_list[location].last_pkts,0,ip_pkt_list_tot*sizeof(unsigned long));
r_list[location].time_pos = curr_table->time_pos;
r_list[location].addr = addr;
r_list[location].ttl = ttl;
@@ -528,11 +529,11 @@
if(info->check_set & IPT_RECENT_CHECK || info->check_set &
IPT_RECENT_UPDATE) {
if(!info->seconds && !info->hit_count) ans =
!info->invert; else ans = info->invert;
if(info->seconds && !info->hit_count) {
-
if(time_before_eq(now,r_list[location].last_seen+info->seconds*HZ)) ans =
!info->invert; else ans = info->invert;
+ if(now <=
r_list[location].last_seen+info->seconds) ans = !info->invert; else ans =
info->invert;
}
if(info->seconds && info->hit_count) {
for(pkt_count = 0, hits_found = 0; pkt_count <
ip_pkt_list_tot; pkt_count++) {
-
if(time_before_eq(now,r_list[location].last_pkts[pkt_count]+info->seconds*HZ))
hits_found++;
+ if(now <=
r_list[location].last_pkts[pkt_count]+info->seconds) hits_found++;
}
if(hits_found >= info->hit_count) ans =
!info->invert; else ans = info->invert;
}
@@ -631,7 +632,7 @@
r_list[location].last_seen = 0;
r_list[location].addr = 0;
r_list[location].ttl = 0;
-
memset(r_list[location].last_pkts,0,ip_pkt_list_tot*sizeof(u_int32_t));
+
memset(r_list[location].last_pkts,0,ip_pkt_list_tot*sizeof(unsigned long));
r_list[location].oldest_pkt = 0;
ans = !info->invert;
}
@@ -734,10 +735,10 @@
memset(curr_table->table,0,sizeof(struct recent_ip_list)*ip_list_tot);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: Allocating %d for
pkt_list.\n",
- sizeof(u_int32_t)*ip_pkt_list_tot*ip_list_tot);
+ sizeof(unsigned long)*ip_pkt_list_tot*ip_list_tot);
#endif
- hold = vmalloc(sizeof(u_int32_t)*ip_pkt_list_tot*ip_list_tot);
+ hold = vmalloc(sizeof(unsigned long)*ip_pkt_list_tot*ip_list_tot);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: After pkt_list
allocation.\n");
#endif
=
-------------------8<-----------------------
-- System Information:
Debian Release: 3.1
Architecture: x86_64
Kernel: Linux 2.6.8-11-amd64-k8-smp
Locale: LANG=en_US, LC_CTYPE=en_US (charmap=ANSI_X3.4-1968) (ignored: LC_ALL
set to C)
--
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