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iptables/SOURCES/0004-nft-Fix-for-broken-rec...

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3.5 KiB

From 4c883007ecf15b5fe18a71688a4383686e7c0026 Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Wed, 22 May 2024 18:26:58 +0200
Subject: [PATCH] nft: Fix for broken recover_rule_compat()
JIRA: https://issues.redhat.com/browse/RHEL-26619
Upstream Status: iptables commit bb1a7a5b297aa271f7f59abbcb891cd94d7fb305
commit bb1a7a5b297aa271f7f59abbcb891cd94d7fb305
Author: Phil Sutter <phil@nwl.cc>
Date: Tue Feb 27 18:47:39 2024 +0100
nft: Fix for broken recover_rule_compat()
When IPv4 rule generator was changed to emit payload instead of
meta expressions for l4proto matches, the code reinserting
NFTNL_RULE_COMPAT_* attributes into rules being reused for counter
zeroing was broken by accident.
Make rule compat recovery aware of the alternative match, basically
reinstating the effect of commit 7a373f6683afb ("nft: Fix -Z for rules
with NFTA_RULE_COMPAT") but add a test case this time to make sure
things stay intact.
Fixes: 69278f9602b43 ("nft: use payload matching for layer 4 protocol")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Phil Sutter <psutter@redhat.com>
---
iptables/nft.c | 27 ++++++++++++++++---
.../nft-only/0011-zero-needs-compat_0 | 12 +++++++++
2 files changed, 35 insertions(+), 4 deletions(-)
create mode 100755 iptables/tests/shell/testcases/nft-only/0011-zero-needs-compat_0
diff --git a/iptables/nft.c b/iptables/nft.c
index 97fd4f4..c4caf29 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -3679,6 +3679,27 @@ const char *nft_strerror(int err)
return strerror(err);
}
+static int l4proto_expr_get_dreg(struct nftnl_expr *e, uint32_t *dregp)
+{
+ const char *name = nftnl_expr_get_str(e, NFTNL_EXPR_NAME);
+ uint32_t poff = offsetof(struct iphdr, protocol);
+ uint32_t pbase = NFT_PAYLOAD_NETWORK_HEADER;
+
+ if (!strcmp(name, "payload") &&
+ nftnl_expr_get_u32(e, NFTNL_EXPR_PAYLOAD_BASE) == pbase &&
+ nftnl_expr_get_u32(e, NFTNL_EXPR_PAYLOAD_OFFSET) == poff &&
+ nftnl_expr_get_u32(e, NFTNL_EXPR_PAYLOAD_LEN) == sizeof(uint8_t)) {
+ *dregp = nftnl_expr_get_u32(e, NFTNL_EXPR_PAYLOAD_DREG);
+ return 0;
+ }
+ if (!strcmp(name, "meta") &&
+ nftnl_expr_get_u32(e, NFTNL_EXPR_META_KEY) == NFT_META_L4PROTO) {
+ *dregp = nftnl_expr_get_u32(e, NFTNL_EXPR_META_DREG);
+ return 0;
+ }
+ return -1;
+}
+
static int recover_rule_compat(struct nftnl_rule *r)
{
struct nftnl_expr_iter *iter;
@@ -3695,12 +3716,10 @@ next_expr:
if (!e)
goto out;
- if (strcmp("meta", nftnl_expr_get_str(e, NFTNL_EXPR_NAME)) ||
- nftnl_expr_get_u32(e, NFTNL_EXPR_META_KEY) != NFT_META_L4PROTO)
+ /* may be 'ip protocol' or 'meta l4proto' with identical RHS */
+ if (l4proto_expr_get_dreg(e, &reg) < 0)
goto next_expr;
- reg = nftnl_expr_get_u32(e, NFTNL_EXPR_META_DREG);
-
e = nftnl_expr_iter_next(iter);
if (!e)
goto out;
diff --git a/iptables/tests/shell/testcases/nft-only/0011-zero-needs-compat_0 b/iptables/tests/shell/testcases/nft-only/0011-zero-needs-compat_0
new file mode 100755
index 0000000..e276a95
--- /dev/null
+++ b/iptables/tests/shell/testcases/nft-only/0011-zero-needs-compat_0
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+[[ $XT_MULTI == *xtables-nft-multi ]] || { echo "skip $XT_MULTI"; exit 0; }
+
+set -e
+
+rule="-p tcp -m tcp --dport 27374 -c 23 42 -j TPROXY --on-port 50080"
+for cmd in iptables ip6tables; do
+ $XT_MULTI $cmd -t mangle -A PREROUTING $rule
+ $XT_MULTI $cmd -t mangle -Z
+ $XT_MULTI $cmd -t mangle -v -S | grep -q -- "${rule/23 42/0 0}"
+done