staging: rtl8723bs: fix OOB read in rtw_action_frame_parse()grafted

rtw_action_frame_parse() takes a frame_len parameter but never
actually checks it before indexing into the frame body:

	const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr);
	...
	c = frame_body[0];
	...
	a = frame_body[1];

frame_body already points 24 bytes (sizeof(struct
ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and
frame_body[1] requires frame_len >= 26. A management action frame
shorter than that (e.g. exactly 24 bytes, the minimum a malicious
peer can send) causes a 1-2 byte out-of-bounds read.

This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and
cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass
attacker/user-influenced frame buffers and lengths straight through.

Add the missing length check before frame_body is dereferenced.

Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
Link: https://patch.msgid.link/20260728125456.32359-3-meatuni001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 153 insertions, 0 deletions

diff --git a/lib/tests/test_ratelimit.c b/lib/tests/test_ratelimit.c
new file mode 100644
index 000000000..e244f8cd4
--- /dev/null
+++ b/lib/tests/test_ratelimit.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <kunit/test.h>
+
+#include <linux/ratelimit.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/cpumask.h>
+
+/* a simple boot-time regression test */
+
+#define TESTRL_INTERVAL (5 * HZ)
+static DEFINE_RATELIMIT_STATE(testrl, TESTRL_INTERVAL, 3);
+
+#define test_ratelimited(test, expected) \
+	KUNIT_ASSERT_EQ(test, ___ratelimit(&testrl, "test_ratelimit_smoke"), (expected))
+
+static void test_ratelimit_smoke(struct kunit *test)
+{
+	// Check settings.
+	KUNIT_ASSERT_GE(test, TESTRL_INTERVAL, 100);
+
+	// Test normal operation.
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, false);
+
+	schedule_timeout_idle(TESTRL_INTERVAL / 2);
+	test_ratelimited(test, false);
+
+	schedule_timeout_idle(TESTRL_INTERVAL * 3 / 4);
+	test_ratelimited(test, true);
+
+	schedule_timeout_idle(2 * TESTRL_INTERVAL);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+
+	schedule_timeout_idle(TESTRL_INTERVAL / 2 );
+	test_ratelimited(test, true);
+	schedule_timeout_idle(TESTRL_INTERVAL * 3 / 4);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, false);
+
+	// Test disabling.
+	testrl.burst = 0;
+	test_ratelimited(test, false);
+	testrl.burst = 2;
+	testrl.interval = 0;
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+
+	// Testing re-enabling.
+	testrl.interval = TESTRL_INTERVAL;
+	test_ratelimited(test, true);
+	test_ratelimited(test, true);
+	test_ratelimited(test, false);
+	test_ratelimited(test, false);
+}
+
+static struct ratelimit_state stressrl = RATELIMIT_STATE_INIT_FLAGS("stressrl", HZ / 10, 3,
+								    RATELIMIT_MSG_ON_RELEASE);
+
+static const int stress_duration = 2 * HZ;
+
+struct stress_kthread {
+	unsigned long nattempts;
+	unsigned long nunlimited;
+	unsigned long nlimited;
+	unsigned long nmissed;
+	struct task_struct *tp;
+};
+
+static int test_ratelimit_stress_child(void *arg)
+{
+	struct stress_kthread *sktp = arg;
+
+	set_user_nice(current, MAX_NICE);
+
+	while (!kthread_should_stop()) {
+		sktp->nattempts++;
+		if (___ratelimit(&stressrl, __func__))
+			sktp->nunlimited++;
+		else
+			sktp->nlimited++;
+		cond_resched();
+	}
+
+	sktp->nmissed = ratelimit_state_reset_miss(&stressrl);
+	return 0;
+}
+
+static void test_ratelimit_stress(struct kunit *test)
+{
+	int i;
+	const int n_stress_kthread = cpumask_weight(cpu_online_mask);
+	struct stress_kthread skt = { 0 };
+	struct stress_kthread *sktp = kzalloc_objs(*sktp, n_stress_kthread);
+	int n_started = 0;
+
+	KUNIT_ASSERT_NOT_NULL_MSG(test, sktp, "Memory allocation failure");
+	for (i = 0; i < n_stress_kthread; i++) {
+		sktp[i].tp = kthread_run(test_ratelimit_stress_child, &sktp[i], "%s/%i",
+					 "test_ratelimit_stress_child", i);
+		if (IS_ERR(sktp[i].tp)) {
+			KUNIT_FAIL(test, "kthread_run failed: %ld", PTR_ERR(sktp[i].tp));
+			goto out_stop;
+		}
+		n_started++;
+		pr_alert("Spawned test_ratelimit_stress_child %d\n", i);
+	}
+	schedule_timeout_idle(stress_duration);
+
+out_stop:
+	for (i = 0; i < n_started; i++) {
+		kthread_stop(sktp[i].tp);
+		skt.nattempts += sktp[i].nattempts;
+		skt.nunlimited += sktp[i].nunlimited;
+		skt.nlimited += sktp[i].nlimited;
+		skt.nmissed += sktp[i].nmissed;
+	}
+	if (n_started == n_stress_kthread) {
+		KUNIT_ASSERT_EQ_MSG(test, skt.nunlimited + skt.nlimited, skt.nattempts,
+				    "Outcomes not equal to attempts");
+		KUNIT_ASSERT_EQ_MSG(test, skt.nlimited, skt.nmissed,
+				    "Misses not equal to limits");
+	}
+
+	kfree(sktp);
+}
+
+static struct kunit_case ratelimit_test_cases[] = {
+	KUNIT_CASE_SLOW(test_ratelimit_smoke),
+	KUNIT_CASE_SLOW(test_ratelimit_stress),
+	{}
+};
+
+static struct kunit_suite ratelimit_test_suite = {
+	.name = "lib_ratelimit",
+	.test_cases = ratelimit_test_cases,
+};
+
+kunit_test_suites(&ratelimit_test_suite);
+
+MODULE_DESCRIPTION("___ratelimit() KUnit test suite");
+MODULE_LICENSE("GPL");