linux-stable.git/net/ipv4/netfilter, branch v6.15

netfilter: fib: avoid lookup if socket is available

2025-03-21T09:12:15+00:00

In case the fib match is used from the input hook we can avoid the fib
lookup if early demux assigned a socket for us: check that the input
interface matches sk-cached one.

Rework the existing 'lo bypass' logic to first check sk, then
for loopback interface type to elide the fib lookup.

This speeds up fib matching a little, before:
93.08 GBit/s (no rules at all)
75.1  GBit/s ("fib saddr . iif oif missing drop" in prerouting)
75.62 GBit/s ("fib saddr . iif oif missing drop" in input)

After:
92.48 GBit/s (no rules at all)
75.62 GBit/s (fib rule in prerouting)
90.37 GBit/s (fib rule in input).

Numbers for the 'no rules' and 'prerouting' are expected to
closely match in-between runs, the 3rd/input test case exercises the
the 'avoid lookup if cached ifindex in sk matches' case.

Test used iperf3 via veth interface, lo can't be used due to existing
loopback test.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_dup4: Convert nf_dup_ipv4_route() to dscp_t.

2024-11-15T10:00:29+00:00

Use ip4h_dscp() instead of reading iph->tos directly.

ip4h_dscp() returns a dscp_t value which is temporarily converted back
to __u8 with inet_dscp_to_dsfield(). When converting ->flowi4_tos to
dscp_t in the future, we'll only have to remove that
inet_dscp_to_dsfield() call.

Signed-off-by: Guillaume Nault 
Signed-off-by: Pablo Neira Ayuso

netfilter: nft_fib: Convert nft_fib4_eval() to dscp_t.

2024-11-15T10:00:29+00:00

Use ip4h_dscp() instead of reading iph->tos directly.

ip4h_dscp() returns a dscp_t value which is temporarily converted back
to __u8 with inet_dscp_to_dsfield(). When converting ->flowi4_tos to
dscp_t in the future, we'll only have to remove that
inet_dscp_to_dsfield() call.

Signed-off-by: Guillaume Nault 
Signed-off-by: Pablo Neira Ayuso

netfilter: rpfilter: Convert rpfilter_mt() to dscp_t.

2024-11-15T10:00:29+00:00

Use ip4h_dscp() instead of reading iph->tos directly.

ip4h_dscp() returns a dscp_t value which is temporarily converted back
to __u8 with inet_dscp_to_dsfield(). When converting ->flowi4_tos to
dscp_t in the future, we'll only have to remove that
inet_dscp_to_dsfield() call.

Signed-off-by: Guillaume Nault 
Signed-off-by: Pablo Neira Ayuso

Merge tag 'nf-next-24-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next

2024-11-07T11:46:04+00:00

Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following series contains Netfilter updates for net-next:

1) Make legacy xtables configs user selectable, from Breno Leitao.

2) Fix a few sparse warnings related to percpu, from Uros Bizjak.

3) Use strscpy_pad, from Justin Stitt.

4) Use nft_trans_elem_alloc() in catchall flush, from Florian Westphal.

5) A series of 7 patches to fix false positive with CONFIG_RCU_LIST=y.
   Florian also sees possible issue with 10 while module load/removal
   when requesting an expression that is available via module. As for
   patch 11, object is being updated so reference on the module already
   exists so I don't see any real issue.

   Florian says:

   "Unfortunately there are many more errors, and not all are false positives.

   First patches pass lockdep_commit_lock_is_held() to the rcu list traversal
   macro so that those splats are avoided.

   The last two patches are real code change as opposed to
   'pass the transaction mutex to relax rcu check':

   Those two lists are not protected by transaction mutex so could be altered
   in parallel.

   This targets nf-next because these are long-standing issues."

netfilter pull request 24-11-07

* tag 'nf-next-24-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next:
  netfilter: nf_tables: must hold rcu read lock while iterating object type list
  netfilter: nf_tables: must hold rcu read lock while iterating expression type list
  netfilter: nf_tables: avoid false-positive lockdep splats with basechain hook
  netfilter: nf_tables: avoid false-positive lockdep splats in set walker
  netfilter: nf_tables: avoid false-positive lockdep splats with flowtables
  netfilter: nf_tables: avoid false-positive lockdep splats with sets
  netfilter: nf_tables: avoid false-positive lockdep splat on rule deletion
  netfilter: nf_tables: prefer nft_trans_elem_alloc helper
  netfilter: nf_tables: replace deprecated strncpy with strscpy_pad
  netfilter: nf_tables: Fix percpu address space issues in nf_tables_api.c
  netfilter: Make legacy configs user selectable
====================

Link: https://patch.msgid.link/20241106234625.168468-1-pablo@netfilter.org
Signed-off-by: Paolo Abeni

netfilter: Make legacy configs user selectable

2024-10-15T08:00:24+00:00

This option makes legacy Netfilter Kconfig user selectable, giving users
the option to configure iptables without enabling any other config.

Make the following KConfig entries user selectable:
 * BRIDGE_NF_EBTABLES_LEGACY
 * IP_NF_ARPTABLES
 * IP_NF_IPTABLES_LEGACY
 * IP6_NF_IPTABLES_LEGACY

Signed-off-by: Breno Leitao 
Signed-off-by: Pablo Neira Ayuso

netfilter: fib: check correct rtable in vrf setups

2024-10-09T21:30:31+00:00

We need to init l3mdev unconditionally, else main routing table is searched
and incorrect result is returned unless strict (iif keyword) matching is
requested.

Next patch adds a selftest for this.

Fixes: 2a8a7c0eaa87 ("netfilter: nft_fib: Fix for rpath check with VRF devices")
Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1761
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_tables: prevent nf_skb_duplicated corruption

2024-09-27T11:55:46+00:00

syzbot found that nf_dup_ipv4() or nf_dup_ipv6() could write
per-cpu variable nf_skb_duplicated in an unsafe way [1].

Disabling preemption as hinted by the splat is not enough,
we have to disable soft interrupts as well.

[1]
BUG: using __this_cpu_write() in preemptible [00000000] code: syz.4.282/6316
 caller is nf_dup_ipv4+0x651/0x8f0 net/ipv4/netfilter/nf_dup_ipv4.c:87
CPU: 0 UID: 0 PID: 6316 Comm: syz.4.282 Not tainted 6.11.0-rc7-syzkaller-00104-g7052622fccb1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 
  __dump_stack lib/dump_stack.c:93 [inline]
  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
  check_preemption_disabled+0x10e/0x120 lib/smp_processor_id.c:49
  nf_dup_ipv4+0x651/0x8f0 net/ipv4/netfilter/nf_dup_ipv4.c:87
  nft_dup_ipv4_eval+0x1db/0x300 net/ipv4/netfilter/nft_dup_ipv4.c:30
  expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
  nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288
  nft_do_chain_ipv4+0x202/0x320 net/netfilter/nft_chain_filter.c:23
  nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
  nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
  nf_hook+0x2c4/0x450 include/linux/netfilter.h:269
  NF_HOOK_COND include/linux/netfilter.h:302 [inline]
  ip_output+0x185/0x230 net/ipv4/ip_output.c:433
  ip_local_out net/ipv4/ip_output.c:129 [inline]
  ip_send_skb+0x74/0x100 net/ipv4/ip_output.c:1495
  udp_send_skb+0xacf/0x1650 net/ipv4/udp.c:981
  udp_sendmsg+0x1c21/0x2a60 net/ipv4/udp.c:1269
  sock_sendmsg_nosec net/socket.c:730 [inline]
  __sock_sendmsg+0x1a6/0x270 net/socket.c:745
  ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
  ___sys_sendmsg net/socket.c:2651 [inline]
  __sys_sendmmsg+0x3b2/0x740 net/socket.c:2737
  __do_sys_sendmmsg net/socket.c:2766 [inline]
  __se_sys_sendmmsg net/socket.c:2763 [inline]
  __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2763
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4ce4f7def9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4ce5d4a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f4ce5135f80 RCX: 00007f4ce4f7def9
RDX: 0000000000000001 RSI: 0000000020005d40 RDI: 0000000000000006
RBP: 00007f4ce4ff0b76 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4ce5135f80 R15: 00007ffd4cbc6d68
 

Fixes: d877f07112f1 ("netfilter: nf_tables: add nft_dup expression")
Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_reject: Fix build warning when CONFIG_BRIDGE_NETFILTER=n

2024-09-26T11:03:02+00:00

If CONFIG_BRIDGE_NETFILTER is not enabled, which is the case for x86_64
defconfig, then building nf_reject_ipv4.c and nf_reject_ipv6.c with W=1
using gcc-14 results in the following warnings, which are treated as
errors:

net/ipv4/netfilter/nf_reject_ipv4.c: In function 'nf_send_reset':
net/ipv4/netfilter/nf_reject_ipv4.c:243:23: error: variable 'niph' set but not used [-Werror=unused-but-set-variable]
  243 |         struct iphdr *niph;
      |                       ^~~~
cc1: all warnings being treated as errors
net/ipv6/netfilter/nf_reject_ipv6.c: In function 'nf_send_reset6':
net/ipv6/netfilter/nf_reject_ipv6.c:286:25: error: variable 'ip6h' set but not used [-Werror=unused-but-set-variable]
  286 |         struct ipv6hdr *ip6h;
      |                         ^~~~
cc1: all warnings being treated as errors

Address this by reducing the scope of these local variables to where
they are used, which is code only compiled when CONFIG_BRIDGE_NETFILTER
enabled.

Compile tested and run through netfilter selftests.

Reported-by: Andy Shevchenko 
Closes: https://lore.kernel.org/netfilter-devel/20240906145513.567781-1-andriy.shevchenko@linux.intel.com/
Signed-off-by: Simon Horman 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_dup4: Unmask upper DSCP bits in nf_dup_ipv4_route()

2024-09-09T13:14:53+00:00

Unmask the upper DSCP bits when calling ip_route_output_key() so that in
the future it could perform the FIB lookup according to the full DSCP
value.

Signed-off-by: Ido Schimmel 
Reviewed-by: Guillaume Nault 
Signed-off-by: David S. Miller