From 2c183a2457d8640aaee3a98fc8fea70bf64d46f2 Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Sat, 29 Feb 2020 02:08:26 +0100
Subject: [PATCH] nft: cache: Make nft_rebuild_cache() respect fake cache

If transaction needed a refresh in nft_action(), restore with flush
would fetch a full cache instead of merely refreshing table list
contained in "fake" cache.

To fix this, nft_rebuild_cache() must distinguish between fake cache and
full rule cache. Therefore introduce NFT_CL_FAKE to be distinguished
from NFT_CL_RULES.

Signed-off-by: Phil Sutter <phil@nwl.cc>
(cherry picked from commit 40ad7793d1884f28767cf58c96e9d76ae0a18db1)

RHEL-only fix: Make nft_rebuild_cache() check 'level' instead of
'h->cache_level' as the latter may be reset by __nft_flush_cache().

Signed-off-by: Phil Sutter <psutter@redhat.com>
---
 iptables/nft-cache.c | 13 +++++++++----
 iptables/nft.h       |  3 ++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/iptables/nft-cache.c b/iptables/nft-cache.c
index bc6e7f7eaebfb..9623b463f0dd5 100644
--- a/iptables/nft-cache.c
+++ b/iptables/nft-cache.c
@@ -480,6 +480,7 @@ __nft_build_cache(struct nft_handle *h, enum nft_cache_level level,
 			break;
 		/* fall through */
 	case NFT_CL_RULES:
+	case NFT_CL_FAKE:
 		break;
 	}
 
@@ -516,7 +517,7 @@ void nft_fake_cache(struct nft_handle *h)
 
 		h->cache->table[type].chains = nftnl_chain_list_alloc();
 	}
-	h->cache_level = NFT_CL_RULES;
+	h->cache_level = NFT_CL_FAKE;
 	mnl_genid_get(h, &h->nft_genid);
 }
 
@@ -629,9 +630,13 @@ void nft_rebuild_cache(struct nft_handle *h)
 	if (h->cache_level)
 		__nft_flush_cache(h);
 
-	h->nft_genid = 0;
-	h->cache_level = NFT_CL_NONE;
-	__nft_build_cache(h, level, NULL, NULL, NULL);
+	if (level == NFT_CL_FAKE) {
+		nft_fake_cache(h);
+	} else {
+		h->nft_genid = 0;
+		h->cache_level = NFT_CL_NONE;
+		__nft_build_cache(h, level, NULL, NULL, NULL);
+	}
 }
 
 void nft_release_cache(struct nft_handle *h)
diff --git a/iptables/nft.h b/iptables/nft.h
index 5cf260a6d2cd3..2094b01455194 100644
--- a/iptables/nft.h
+++ b/iptables/nft.h
@@ -32,7 +32,8 @@ enum nft_cache_level {
 	NFT_CL_TABLES,
 	NFT_CL_CHAINS,
 	NFT_CL_SETS,
-	NFT_CL_RULES
+	NFT_CL_RULES,
+	NFT_CL_FAKE	/* must be last entry */
 };
 
 struct nft_cache {
-- 
2.28.0