[PATCH nft] libnftables: Drop cache in -c/--check mode

[PATCH nft] libnftables: Drop cache in -c/--check mode

[Pablo Neira Ayuso]

Extend e0aace943412 ("libnftables: Drop cache in error case") to also
drop the cache with -c/--check, this is a dry run mode and kernel does
not get any update.

This fixes a bug with -o/--optimize, which first runs in an implicit
-c/--check mode to validate that the ruleset is correct, then it
provides the proposed optimization. In this case, if the cache is not
emptied, old objects in the cache refer to scanner data that was
already released, which triggers BUG like this:

 BUG: invalid input descriptor type 151665524
 nft: erec.c:161: erec_print: Assertion `0' failed.
 Aborted

This bug was triggered in a ruleset that contains a set for geoip
filtering. This patch also extends tests/shell to cover this case.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/libnftables.c                                     |  7 +++++--
 .../optimizations/dumps/skip_unsupported.nft          | 11 +++++++++++
 tests/shell/testcases/optimizations/skip_unsupported  | 11 +++++++++++
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/libnftables.c b/src/libnftables.c
index 6fc4f7db6760..e214abb69cf2 100644
--- a/src/libnftables.c
+++ b/src/libnftables.c
@@ -607,8 +607,10 @@ err:
 	    nft_output_json(&nft->output) &&
 	    nft_output_echo(&nft->output))
 		json_print_echo(nft);
-	if (rc)
+
+	if (rc || nft->check)
 		nft_cache_release(&nft->cache);
+
 	return rc;
 }
 
@@ -713,7 +715,8 @@ err:
 	    nft_output_json(&nft->output) &&
 	    nft_output_echo(&nft->output))
 		json_print_echo(nft);
-	if (rc)
+
+	if (rc || nft->check)
 		nft_cache_release(&nft->cache);
 
 	scope_release(nft->state->scopes[0]);
diff --git a/tests/shell/testcases/optimizations/dumps/skip_unsupported.nft b/tests/shell/testcases/optimizations/dumps/skip_unsupported.nft
index 43b6578dc704..f24855e7b5e1 100644
--- a/tests/shell/testcases/optimizations/dumps/skip_unsupported.nft
+++ b/tests/shell/testcases/optimizations/dumps/skip_unsupported.nft
@@ -1,4 +1,15 @@
 table inet x {
+	set GEOIP_CC_wan-lan_120 {
+		type ipv4_addr
+		flags interval
+		elements = { 1.32.128.0/18, 1.32.200.0-1.32.204.128,
+			     1.32.207.0/24, 1.32.216.118-1.32.216.255,
+			     1.32.219.0-1.32.222.255, 1.32.226.0/23,
+			     1.32.231.0/24, 1.32.233.0/24,
+			     1.32.238.0/23, 1.32.240.0/24,
+			     223.223.220.0/22, 223.255.254.0/24 }
+	}
+
 	chain y {
 		ip saddr 1.2.3.4 tcp dport 80 meta mark set 0x0000000a accept
 		ip saddr 1.2.3.4 tcp dport 81 meta mark set 0x0000000b accept
diff --git a/tests/shell/testcases/optimizations/skip_unsupported b/tests/shell/testcases/optimizations/skip_unsupported
index 9313c302048c..6baa8280a9b5 100755
--- a/tests/shell/testcases/optimizations/skip_unsupported
+++ b/tests/shell/testcases/optimizations/skip_unsupported
@@ -3,6 +3,17 @@
 set -e
 
 RULESET="table inet x {
+	set GEOIP_CC_wan-lan_120 {
+		type ipv4_addr
+		flags interval
+		elements = { 1.32.128.0/18, 1.32.200.0-1.32.204.128,
+			     1.32.207.0/24, 1.32.216.118-1.32.216.255,
+			     1.32.219.0-1.32.222.255, 1.32.226.0/23,
+			     1.32.231.0/24, 1.32.233.0/24,
+			     1.32.238.0/23, 1.32.240.0/24,
+			     223.223.220.0/22, 223.255.254.0/24 }
+	}
+
 	chain y {
 		ip saddr 1.2.3.4 tcp dport 80 meta mark set 10 accept
 		ip saddr 1.2.3.4 tcp dport 81 meta mark set 11 accept
-- 
2.30.2