[PATCH net 0/4] Netfilter fixes for net

[PATCH net 0/4] Netfilter fixes for net

[Pablo Neira Ayuso]

Hi,

The following patchset contains Netfilter fixes for net:

1) Fix incorrect documentation in uapi/linux/netfilter/nf_tables.h
   regarding flowtable hooks, from Phil Sutter.

2) Fix nft_audit.sh selftests with newer nft binaries, due to different
   (valid) audit output, also from Phil.

3) Disable BH when duplicating packets via nf_dup infrastructure,
   otherwise race on nf_skb_duplicated for locally generated traffic.
   From Eric.

4) Missing return in callback of selftest C program, from zhang jiao.

Please, pull these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git nf-24-10-02

Thanks.

----------------------------------------------------------------

The following changes since commit aef3a58b06fa9d452ba863999ac34be1d0c65172:

  Merge tag 'nf-24-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf (2024-09-26 15:47:11 +0200)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git nf-24-10-02

for you to fetch changes up to 10dbd23633f0433f8d13c2803d687b36a675ef60:

  selftests: netfilter: Add missing return value (2024-09-27 13:59:12 +0200)

----------------------------------------------------------------
netfilter pull request 24-10-02

----------------------------------------------------------------
Eric Dumazet (1):
      netfilter: nf_tables: prevent nf_skb_duplicated corruption

Phil Sutter (2):
      netfilter: uapi: NFTA_FLOWTABLE_HOOK is NLA_NESTED
      selftests: netfilter: Fix nft_audit.sh for newer nft binaries

zhang jiao (1):
      selftests: netfilter: Add missing return value

 include/uapi/linux/netfilter/nf_tables.h           |  2 +-
 net/ipv4/netfilter/nf_dup_ipv4.c                   |  7 ++-
 net/ipv6/netfilter/nf_dup_ipv6.c                   |  7 ++-
 .../selftests/net/netfilter/conntrack_dump_flush.c |  1 +
 tools/testing/selftests/net/netfilter/nft_audit.sh | 57 +++++++++++-----------
 5 files changed, 41 insertions(+), 33 deletions(-)

[PATCH net 1/4] netfilter: uapi: NFTA_FLOWTABLE_HOOK is NLA_NESTED

[Pablo Neira Ayuso]

From: Phil Sutter <phil@nwl.cc>

Fix the comment which incorrectly defines it as NLA_U32.

Fixes: 3b49e2e94e6e ("netfilter: nf_tables: add flow table netlink frontend")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/uapi/linux/netfilter/nf_tables.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index d6476ca5d7a6..9e9079321380 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1694,7 +1694,7 @@ enum nft_flowtable_flags {
  *
  * @NFTA_FLOWTABLE_TABLE: name of the table containing the expression (NLA_STRING)
  * @NFTA_FLOWTABLE_NAME: name of this flow table (NLA_STRING)
- * @NFTA_FLOWTABLE_HOOK: netfilter hook configuration(NLA_U32)
+ * @NFTA_FLOWTABLE_HOOK: netfilter hook configuration (NLA_NESTED)
  * @NFTA_FLOWTABLE_USE: number of references to this flow table (NLA_U32)
  * @NFTA_FLOWTABLE_HANDLE: object handle (NLA_U64)
  * @NFTA_FLOWTABLE_FLAGS: flags (NLA_U32)
-- 
2.30.2

[PATCH net 2/4] selftests: netfilter: Fix nft_audit.sh for newer nft binaries

[Pablo Neira Ayuso]

From: Phil Sutter <phil@nwl.cc>

As a side-effect of nftables' commit dbff26bfba833 ("cache: consolidate
reset command"), audit logs changed when more objects were reset than
fit into a single netlink message.

Since the objects' distribution in netlink messages is not relevant,
implement a summarizing function which combines repeated audit logs into
a single one with summed up 'entries=' value.

Fixes: 203bb9d39866 ("selftests: netfilter: Extend nft_audit.sh")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 .../selftests/net/netfilter/nft_audit.sh      | 57 ++++++++++---------
 1 file changed, 29 insertions(+), 28 deletions(-)

diff --git a/tools/testing/selftests/net/netfilter/nft_audit.sh b/tools/testing/selftests/net/netfilter/nft_audit.sh
index 902f8114bc80..87f2b4c725aa 100755
--- a/tools/testing/selftests/net/netfilter/nft_audit.sh
+++ b/tools/testing/selftests/net/netfilter/nft_audit.sh
@@ -48,12 +48,31 @@ logread_pid=$!
 trap 'kill $logread_pid; rm -f $logfile $rulefile' EXIT
 exec 3<"$logfile"
 
+lsplit='s/^\(.*\) entries=\([^ ]*\) \(.*\)$/pfx="\1"\nval="\2"\nsfx="\3"/'
+summarize_logs() {
+	sum=0
+	while read line; do
+		eval $(sed "$lsplit" <<< "$line")
+		[[ $sum -gt 0 ]] && {
+			[[ "$pfx $sfx" == "$tpfx $tsfx" ]] && {
+				let "sum += val"
+				continue
+			}
+			echo "$tpfx entries=$sum $tsfx"
+		}
+		tpfx="$pfx"
+		tsfx="$sfx"
+		sum=$val
+	done
+	echo "$tpfx entries=$sum $tsfx"
+}
+
 do_test() { # (cmd, log)
 	echo -n "testing for cmd: $1 ... "
 	cat <&3 >/dev/null
 	$1 >/dev/null || exit 1
 	sleep 0.1
-	res=$(diff -a -u <(echo "$2") - <&3)
+	res=$(diff -a -u <(echo "$2") <(summarize_logs <&3))
 	[ $? -eq 0 ] && { echo "OK"; return; }
 	echo "FAIL"
 	grep -v '^\(---\|+++\|@@\)' <<< "$res"
@@ -152,31 +171,17 @@ do_test 'nft reset rules t1 c2' \
 'table=t1 family=2 entries=3 op=nft_reset_rule'
 
 do_test 'nft reset rules table t1' \
-'table=t1 family=2 entries=3 op=nft_reset_rule
-table=t1 family=2 entries=3 op=nft_reset_rule
-table=t1 family=2 entries=3 op=nft_reset_rule'
+'table=t1 family=2 entries=9 op=nft_reset_rule'
 
 do_test 'nft reset rules t2 c3' \
-'table=t2 family=2 entries=189 op=nft_reset_rule
-table=t2 family=2 entries=188 op=nft_reset_rule
-table=t2 family=2 entries=126 op=nft_reset_rule'
+'table=t2 family=2 entries=503 op=nft_reset_rule'
 
 do_test 'nft reset rules t2' \
-'table=t2 family=2 entries=3 op=nft_reset_rule
-table=t2 family=2 entries=3 op=nft_reset_rule
-table=t2 family=2 entries=186 op=nft_reset_rule
-table=t2 family=2 entries=188 op=nft_reset_rule
-table=t2 family=2 entries=129 op=nft_reset_rule'
+'table=t2 family=2 entries=509 op=nft_reset_rule'
 
 do_test 'nft reset rules' \
-'table=t1 family=2 entries=3 op=nft_reset_rule
-table=t1 family=2 entries=3 op=nft_reset_rule
-table=t1 family=2 entries=3 op=nft_reset_rule
-table=t2 family=2 entries=3 op=nft_reset_rule
-table=t2 family=2 entries=3 op=nft_reset_rule
-table=t2 family=2 entries=180 op=nft_reset_rule
-table=t2 family=2 entries=188 op=nft_reset_rule
-table=t2 family=2 entries=135 op=nft_reset_rule'
+'table=t1 family=2 entries=9 op=nft_reset_rule
+table=t2 family=2 entries=509 op=nft_reset_rule'
 
 # resetting sets and elements
 
@@ -200,13 +205,11 @@ do_test 'nft reset counters t1' \
 'table=t1 family=2 entries=1 op=nft_reset_obj'
 
 do_test 'nft reset counters t2' \
-'table=t2 family=2 entries=342 op=nft_reset_obj
-table=t2 family=2 entries=158 op=nft_reset_obj'
+'table=t2 family=2 entries=500 op=nft_reset_obj'
 
 do_test 'nft reset counters' \
 'table=t1 family=2 entries=1 op=nft_reset_obj
-table=t2 family=2 entries=341 op=nft_reset_obj
-table=t2 family=2 entries=159 op=nft_reset_obj'
+table=t2 family=2 entries=500 op=nft_reset_obj'
 
 # resetting quotas
 
@@ -217,13 +220,11 @@ do_test 'nft reset quotas t1' \
 'table=t1 family=2 entries=1 op=nft_reset_obj'
 
 do_test 'nft reset quotas t2' \
-'table=t2 family=2 entries=315 op=nft_reset_obj
-table=t2 family=2 entries=185 op=nft_reset_obj'
+'table=t2 family=2 entries=500 op=nft_reset_obj'
 
 do_test 'nft reset quotas' \
 'table=t1 family=2 entries=1 op=nft_reset_obj
-table=t2 family=2 entries=314 op=nft_reset_obj
-table=t2 family=2 entries=186 op=nft_reset_obj'
+table=t2 family=2 entries=500 op=nft_reset_obj'
 
 # deleting rules
 
-- 
2.30.2

[PATCH net 3/4] netfilter: nf_tables: prevent nf_skb_duplicated corruption

[Pablo Neira Ayuso]

From: Eric Dumazet <edumazet@google.com>

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:
 <TASK>
  __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
 </TASK>

Fixes: d877f07112f1 ("netfilter: nf_tables: add nft_dup expression")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/ipv4/netfilter/nf_dup_ipv4.c | 7 +++++--
 net/ipv6/netfilter/nf_dup_ipv6.c | 7 +++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/netfilter/nf_dup_ipv4.c b/net/ipv4/netfilter/nf_dup_ipv4.c
index f4aed0789d69..ec94ee1051c7 100644
--- a/net/ipv4/netfilter/nf_dup_ipv4.c
+++ b/net/ipv4/netfilter/nf_dup_ipv4.c
@@ -53,8 +53,9 @@ void nf_dup_ipv4(struct net *net, struct sk_buff *skb, unsigned int hooknum,
 {
 	struct iphdr *iph;
 
+	local_bh_disable();
 	if (this_cpu_read(nf_skb_duplicated))
-		return;
+		goto out;
 	/*
 	 * Copy the skb, and route the copy. Will later return %XT_CONTINUE for
 	 * the original skb, which should continue on its way as if nothing has
@@ -62,7 +63,7 @@ void nf_dup_ipv4(struct net *net, struct sk_buff *skb, unsigned int hooknum,
 	 */
 	skb = pskb_copy(skb, GFP_ATOMIC);
 	if (skb == NULL)
-		return;
+		goto out;
 
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	/* Avoid counting cloned packets towards the original connection. */
@@ -91,6 +92,8 @@ void nf_dup_ipv4(struct net *net, struct sk_buff *skb, unsigned int hooknum,
 	} else {
 		kfree_skb(skb);
 	}
+out:
+	local_bh_enable();
 }
 EXPORT_SYMBOL_GPL(nf_dup_ipv4);
 
diff --git a/net/ipv6/netfilter/nf_dup_ipv6.c b/net/ipv6/netfilter/nf_dup_ipv6.c
index a0a2de30be3e..0c39c77fe8a8 100644
--- a/net/ipv6/netfilter/nf_dup_ipv6.c
+++ b/net/ipv6/netfilter/nf_dup_ipv6.c
@@ -47,11 +47,12 @@ static bool nf_dup_ipv6_route(struct net *net, struct sk_buff *skb,
 void nf_dup_ipv6(struct net *net, struct sk_buff *skb, unsigned int hooknum,
 		 const struct in6_addr *gw, int oif)
 {
+	local_bh_disable();
 	if (this_cpu_read(nf_skb_duplicated))
-		return;
+		goto out;
 	skb = pskb_copy(skb, GFP_ATOMIC);
 	if (skb == NULL)
-		return;
+		goto out;
 
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 	nf_reset_ct(skb);
@@ -69,6 +70,8 @@ void nf_dup_ipv6(struct net *net, struct sk_buff *skb, unsigned int hooknum,
 	} else {
 		kfree_skb(skb);
 	}
+out:
+	local_bh_enable();
 }
 EXPORT_SYMBOL_GPL(nf_dup_ipv6);
 
-- 
2.30.2

[PATCH net 4/4] selftests: netfilter: Add missing return value

[Pablo Neira Ayuso]

From: zhang jiao <zhangjiao2@cmss.chinamobile.com>

There is no return value in count_entries, just add it.

Fixes: eff3c558bb7e ("netfilter: ctnetlink: support filtering by zone")
Signed-off-by: zhang jiao <zhangjiao2@cmss.chinamobile.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 tools/testing/selftests/net/netfilter/conntrack_dump_flush.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c b/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c
index bd9317bf5ada..dc056fec993b 100644
--- a/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c
+++ b/tools/testing/selftests/net/netfilter/conntrack_dump_flush.c
@@ -207,6 +207,7 @@ static int conntrack_data_generate_v6(struct mnl_socket *sock,
 static int count_entries(const struct nlmsghdr *nlh, void *data)
 {
 	reply_counter++;
+	return MNL_CB_OK;
 }
 
 static int conntracK_count_zone(struct mnl_socket *sock, uint16_t zone)
-- 
2.30.2

Re: [PATCH net 1/4] netfilter: uapi: NFTA_FLOWTABLE_HOOK is NLA_NESTED

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Pablo Neira Ayuso <pablo@netfilter.org>:

On Wed,  2 Oct 2024 22:24:18 +0200 you wrote:
> From: Phil Sutter <phil@nwl.cc>
> 
> Fix the comment which incorrectly defines it as NLA_U32.
> 
> Fixes: 3b49e2e94e6e ("netfilter: nf_tables: add flow table netlink frontend")
> Signed-off-by: Phil Sutter <phil@nwl.cc>
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> 
> [...]

Here is the summary with links:
  - [net,1/4] netfilter: uapi: NFTA_FLOWTABLE_HOOK is NLA_NESTED
    https://git.kernel.org/netdev/net/c/76f1ed087b56
  - [net,2/4] selftests: netfilter: Fix nft_audit.sh for newer nft binaries
    https://git.kernel.org/netdev/net/c/8a8901564451
  - [net,3/4] netfilter: nf_tables: prevent nf_skb_duplicated corruption
    https://git.kernel.org/netdev/net/c/92ceba94de6f
  - [net,4/4] selftests: netfilter: Add missing return value
    https://git.kernel.org/netdev/net/c/10dbd23633f0

You are awesome, thank you!
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