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, 224 insertions, 0 deletions

diff --git a/lib/tests/kfifo_kunit.c b/lib/tests/kfifo_kunit.c
new file mode 100644
index 000000000..a85eedc31
--- /dev/null
+++ b/lib/tests/kfifo_kunit.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test for the generic kernel FIFO implementation.
+ *
+ * Copyright (C) 2024 Diego Vieira <diego.daniel.professional@gmail.com>
+ */
+#include <kunit/test.h>
+
+#include <linux/kfifo.h>
+
+#define KFIFO_SIZE 32
+#define N_ELEMENTS 5
+
+static void kfifo_test_reset_should_clear_the_fifo(struct kunit *test)
+{
+	DEFINE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	kfifo_put(&my_fifo, 1);
+	kfifo_put(&my_fifo, 2);
+	kfifo_put(&my_fifo, 3);
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 3);
+
+	kfifo_reset(&my_fifo);
+
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 0);
+	KUNIT_EXPECT_TRUE(test, kfifo_is_empty(&my_fifo));
+}
+
+static void kfifo_test_define_should_define_an_empty_fifo(struct kunit *test)
+{
+	DEFINE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	KUNIT_EXPECT_TRUE(test, kfifo_initialized(&my_fifo));
+	KUNIT_EXPECT_TRUE(test, kfifo_is_empty(&my_fifo));
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 0);
+}
+
+static void kfifo_test_len_should_ret_n_of_stored_elements(struct kunit *test)
+{
+	u8 buffer1[N_ELEMENTS];
+
+	for (int i = 0; i < N_ELEMENTS; i++)
+		buffer1[i] = i + 1;
+
+	DEFINE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 0);
+
+	kfifo_in(&my_fifo, buffer1, N_ELEMENTS);
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), N_ELEMENTS);
+
+	kfifo_in(&my_fifo, buffer1, N_ELEMENTS);
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), N_ELEMENTS * 2);
+
+	kfifo_reset(&my_fifo);
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 0);
+}
+
+static void kfifo_test_put_should_insert_and_get_should_pop(struct kunit *test)
+{
+	u8 out_data = 0;
+	int processed_elements;
+	u8 elements[] = { 3, 5, 11 };
+
+	DEFINE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	// If the fifo is empty, get returns 0
+	processed_elements = kfifo_get(&my_fifo, &out_data);
+	KUNIT_EXPECT_EQ(test, processed_elements, 0);
+	KUNIT_EXPECT_EQ(test, out_data, 0);
+
+	for (int i = 0; i < 3; i++)
+		kfifo_put(&my_fifo, elements[i]);
+
+	for (int i = 0; i < 3; i++) {
+		processed_elements = kfifo_get(&my_fifo, &out_data);
+		KUNIT_EXPECT_EQ(test, processed_elements, 1);
+		KUNIT_EXPECT_EQ(test, out_data, elements[i]);
+	}
+}
+
+static void kfifo_test_in_should_insert_multiple_elements(struct kunit *test)
+{
+	u8 in_buffer[] = { 11, 25, 65 };
+	u8 out_data;
+	int processed_elements;
+
+	DEFINE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	kfifo_in(&my_fifo, in_buffer, 3);
+
+	for (int i = 0; i < 3; i++) {
+		processed_elements = kfifo_get(&my_fifo, &out_data);
+		KUNIT_EXPECT_EQ(test, processed_elements, 1);
+		KUNIT_EXPECT_EQ(test, out_data, in_buffer[i]);
+	}
+}
+
+static void kfifo_test_out_should_pop_multiple_elements(struct kunit *test)
+{
+	u8 in_buffer[] = { 11, 25, 65 };
+	u8 out_buffer[3];
+	int copied_elements;
+
+	DEFINE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	for (int i = 0; i < 3; i++)
+		kfifo_put(&my_fifo, in_buffer[i]);
+
+	copied_elements = kfifo_out(&my_fifo, out_buffer, 3);
+	KUNIT_EXPECT_EQ(test, copied_elements, 3);
+
+	for (int i = 0; i < 3; i++)
+		KUNIT_EXPECT_EQ(test, out_buffer[i], in_buffer[i]);
+	KUNIT_EXPECT_TRUE(test, kfifo_is_empty(&my_fifo));
+}
+
+static void kfifo_test_dec_init_should_define_an_empty_fifo(struct kunit *test)
+{
+	DECLARE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	INIT_KFIFO(my_fifo);
+
+	// my_fifo is a struct with an inplace buffer
+	KUNIT_EXPECT_FALSE(test, __is_kfifo_ptr(&my_fifo));
+
+	KUNIT_EXPECT_TRUE(test, kfifo_initialized(&my_fifo));
+}
+
+static void kfifo_test_define_should_equal_declare_init(struct kunit *test)
+{
+	// declare a variable my_fifo of type struct kfifo of u8
+	DECLARE_KFIFO(my_fifo1, u8, KFIFO_SIZE);
+	// initialize the my_fifo variable
+	INIT_KFIFO(my_fifo1);
+
+	// DEFINE_KFIFO declares the variable with the initial value
+	// essentially the same as calling DECLARE_KFIFO and INIT_KFIFO
+	DEFINE_KFIFO(my_fifo2, u8, KFIFO_SIZE);
+
+	// my_fifo1 and my_fifo2 have the same size
+	KUNIT_EXPECT_EQ(test, sizeof(my_fifo1), sizeof(my_fifo2));
+	KUNIT_EXPECT_EQ(test, kfifo_initialized(&my_fifo1),
+			kfifo_initialized(&my_fifo2));
+	KUNIT_EXPECT_EQ(test, kfifo_is_empty(&my_fifo1),
+			kfifo_is_empty(&my_fifo2));
+}
+
+static void kfifo_test_alloc_should_initiliaze_a_ptr_fifo(struct kunit *test)
+{
+	int ret;
+	DECLARE_KFIFO_PTR(my_fifo, u8);
+
+	INIT_KFIFO(my_fifo);
+
+	// kfifo_initialized returns false signaling the buffer pointer is NULL
+	KUNIT_EXPECT_FALSE(test, kfifo_initialized(&my_fifo));
+
+	// kfifo_alloc allocates the buffer
+	ret = kfifo_alloc(&my_fifo, KFIFO_SIZE, GFP_KERNEL);
+	KUNIT_EXPECT_EQ_MSG(test, ret, 0, "Memory allocation should succeed");
+	KUNIT_EXPECT_TRUE(test, kfifo_initialized(&my_fifo));
+
+	// kfifo_free frees the buffer
+	kfifo_free(&my_fifo);
+}
+
+static void kfifo_test_peek_should_not_remove_elements(struct kunit *test)
+{
+	u8 out_data;
+	int processed_elements;
+
+	DEFINE_KFIFO(my_fifo, u8, KFIFO_SIZE);
+
+	// If the fifo is empty, peek returns 0
+	processed_elements = kfifo_peek(&my_fifo, &out_data);
+	KUNIT_EXPECT_EQ(test, processed_elements, 0);
+
+	kfifo_put(&my_fifo, 3);
+	kfifo_put(&my_fifo, 5);
+	kfifo_put(&my_fifo, 11);
+
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 3);
+
+	processed_elements = kfifo_peek(&my_fifo, &out_data);
+	KUNIT_EXPECT_EQ(test, processed_elements, 1);
+	KUNIT_EXPECT_EQ(test, out_data, 3);
+
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 3);
+
+	// Using peek doesn't remove the element
+	// so the read element and the fifo length
+	// remains the same
+	processed_elements = kfifo_peek(&my_fifo, &out_data);
+	KUNIT_EXPECT_EQ(test, processed_elements, 1);
+	KUNIT_EXPECT_EQ(test, out_data, 3);
+
+	KUNIT_EXPECT_EQ(test, kfifo_len(&my_fifo), 3);
+}
+
+static struct kunit_case kfifo_test_cases[] = {
+	KUNIT_CASE(kfifo_test_reset_should_clear_the_fifo),
+	KUNIT_CASE(kfifo_test_define_should_define_an_empty_fifo),
+	KUNIT_CASE(kfifo_test_len_should_ret_n_of_stored_elements),
+	KUNIT_CASE(kfifo_test_put_should_insert_and_get_should_pop),
+	KUNIT_CASE(kfifo_test_in_should_insert_multiple_elements),
+	KUNIT_CASE(kfifo_test_out_should_pop_multiple_elements),
+	KUNIT_CASE(kfifo_test_dec_init_should_define_an_empty_fifo),
+	KUNIT_CASE(kfifo_test_define_should_equal_declare_init),
+	KUNIT_CASE(kfifo_test_alloc_should_initiliaze_a_ptr_fifo),
+	KUNIT_CASE(kfifo_test_peek_should_not_remove_elements),
+	{},
+};
+
+static struct kunit_suite kfifo_test_module = {
+	.name = "kfifo",
+	.test_cases = kfifo_test_cases,
+};
+
+kunit_test_suites(&kfifo_test_module);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Diego Vieira <diego.daniel.professional@gmail.com>");
+MODULE_DESCRIPTION("KUnit test for the kernel FIFO");