extensions: support for per-extension instance "global" variable space

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

1 files changed, 18 insertions, 0 deletions

diff --git a/iptables/xshared.c b/iptables/xshared.c
index 55ce5504..79da507d 100644
--- a/iptables/xshared.c
+++ b/iptables/xshared.c
@@ -209,12 +209,30 @@ int subcmd_main(int argc, char **argv, const struct subcommand *cb)
 
 void xs_init_target(struct xtables_target *target)
 {
+	if (target->udata_size != 0) {
+		free(target->udata);
+		target->udata = calloc(1, target->udata_size);
+		if (target->udata == NULL)
+			xtables_error(RESOURCE_PROBLEM, "malloc");
+	}
 	if (target->init != NULL)
 		target->init(target->t);
 }
 
 void xs_init_match(struct xtables_match *match)
 {
+	if (match->udata_size != 0) {
+		/*
+		 * As soon as a subsequent instance of the same match
+		 * is used, e.g. "-m time -m time", the first instance
+		 * is no longer reachable anyway, so we can free udata.
+		 * Same goes for target.
+		 */
+		free(match->udata);
+		match->udata = calloc(1, match->udata_size);
+		if (match->udata == NULL)
+			xtables_error(RESOURCE_PROBLEM, "malloc");
+	}
 	if (match->init != NULL)
 		match->init(match->m);
 }