netdev - [PATCH] samples/landlock: Fix incorrect free in populate_ruleset

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Message-ID: <20240326095625.3576164-1-ivanov.mikhail1@huawei-partners.com>
Date: Tue, 26 Mar 2024 17:56:25 +0800
From: Ivanov Mikhail <ivanov.mikhail1@...wei-partners.com>
To: <mic@...ikod.net>
CC: <willemdebruijn.kernel@...il.com>, <gnoack3000@...il.com>,
	<linux-security-module@...r.kernel.org>, <netdev@...r.kernel.org>,
	<netfilter-devel@...r.kernel.org>, <yusongping@...wei.com>,
	<artem.kuzin@...wei.com>, <konstantin.meskhidze@...wei.com>
Subject: [PATCH] samples/landlock: Fix incorrect free in populate_ruleset_net

Pointer env_port_name changes after strsep(). Memory allocated via
strdup() will not be freed if landlock_add_rule() returns non-zero value.

Fixes: 5e990dcef12e ("samples/landlock: Support TCP restrictions")
Signed-off-by: Ivanov Mikhail <ivanov.mikhail1@...wei-partners.com>
Reviewed-by: Konstantin Meskhidze <konstantin.meskhidze@...wei.com>
---
 samples/landlock/sandboxer.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index 32e930c853bb..8b8ecd65c28c 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -153,7 +153,7 @@ static int populate_ruleset_net(const char *const env_var, const int ruleset_fd,
 				const __u64 allowed_access)
 {
 	int ret = 1;
-	char *env_port_name, *strport;
+	char *env_port_name, *env_port_name_next, *strport;
 	struct landlock_net_port_attr net_port = {
 		.allowed_access = allowed_access,
 		.port = 0,
@@ -165,7 +165,8 @@ static int populate_ruleset_net(const char *const env_var, const int ruleset_fd,
 	env_port_name = strdup(env_port_name);
 	unsetenv(env_var);
 
-	while ((strport = strsep(&env_port_name, ENV_DELIMITER))) {
+	env_port_name_next = env_port_name;
+	while ((strport = strsep(&env_port_name_next, ENV_DELIMITER))) {
 		net_port.port = atoi(strport);
 		if (landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_PORT,
 				      &net_port, 0)) {
-- 
2.34.1