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, 151 insertions, 0 deletions

diff --git a/net/mptcp/token_test.c b/net/mptcp/token_test.c
new file mode 100644
index 000000000..4fc39fa2e
--- /dev/null
+++ b/net/mptcp/token_test.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+
+#include "protocol.h"
+
+static struct mptcp_subflow_request_sock *build_req_sock(struct kunit *test)
+{
+	struct mptcp_subflow_request_sock *req;
+
+	req = kunit_kzalloc(test, sizeof(struct mptcp_subflow_request_sock),
+			    GFP_USER);
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, req);
+	mptcp_token_init_request((struct request_sock *)req);
+	sock_net_set((struct sock *)req, &init_net);
+	return req;
+}
+
+static void mptcp_token_test_req_basic(struct kunit *test)
+{
+	struct mptcp_subflow_request_sock *req = build_req_sock(test);
+	struct mptcp_sock *null_msk = NULL;
+
+	KUNIT_ASSERT_EQ(test, 0,
+			mptcp_token_new_request((struct request_sock *)req));
+	KUNIT_EXPECT_NE(test, 0, (int)req->token);
+	KUNIT_EXPECT_PTR_EQ(test, null_msk, mptcp_token_get_sock(&init_net, req->token));
+
+	/* cleanup */
+	mptcp_token_destroy_request((struct request_sock *)req);
+}
+
+static struct inet_connection_sock *build_icsk(struct kunit *test)
+{
+	struct inet_connection_sock *icsk;
+
+	icsk = kunit_kzalloc(test, sizeof(struct inet_connection_sock),
+			     GFP_USER);
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, icsk);
+	return icsk;
+}
+
+static struct mptcp_subflow_context *build_ctx(struct kunit *test)
+{
+	struct mptcp_subflow_context *ctx;
+
+	ctx = kunit_kzalloc(test, sizeof(struct mptcp_subflow_context),
+			    GFP_USER);
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, ctx);
+	return ctx;
+}
+
+static struct mptcp_sock *build_msk(struct kunit *test)
+{
+	struct mptcp_sock *msk;
+	struct sock *sk;
+
+	msk = kunit_kzalloc(test, sizeof(struct mptcp_sock), GFP_USER);
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, msk);
+	refcount_set(&((struct sock *)msk)->sk_refcnt, 1);
+	sock_net_set((struct sock *)msk, &init_net);
+
+	sk = (struct sock *)msk;
+
+	/* be sure the token helpers can dereference sk->sk_prot */
+	sk->sk_prot = &tcp_prot;
+	sk->sk_protocol = IPPROTO_MPTCP;
+
+	return msk;
+}
+
+static void mptcp_token_test_msk_basic(struct kunit *test)
+{
+	struct inet_connection_sock *icsk = build_icsk(test);
+	struct mptcp_subflow_context *ctx = build_ctx(test);
+	struct mptcp_sock *msk = build_msk(test);
+	struct mptcp_sock *null_msk = NULL;
+	struct sock *sk;
+
+	rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
+	ctx->conn = (struct sock *)msk;
+	sk = (struct sock *)msk;
+
+	KUNIT_ASSERT_EQ(test, 0,
+			mptcp_token_new_connect((struct sock *)icsk));
+	KUNIT_EXPECT_NE(test, 0, (int)ctx->token);
+	KUNIT_EXPECT_EQ(test, ctx->token, msk->token);
+	KUNIT_EXPECT_PTR_EQ(test, msk, mptcp_token_get_sock(&init_net, ctx->token));
+	KUNIT_EXPECT_EQ(test, 2, (int)refcount_read(&sk->sk_refcnt));
+
+	mptcp_token_destroy(msk);
+	KUNIT_EXPECT_PTR_EQ(test, null_msk, mptcp_token_get_sock(&init_net, ctx->token));
+}
+
+static void mptcp_token_test_accept(struct kunit *test)
+{
+	struct mptcp_subflow_request_sock *req = build_req_sock(test);
+	struct mptcp_sock *msk = build_msk(test);
+
+	KUNIT_ASSERT_EQ(test, 0,
+			mptcp_token_new_request((struct request_sock *)req));
+	msk->token = req->token;
+	mptcp_token_accept(req, msk);
+	KUNIT_EXPECT_PTR_EQ(test, msk, mptcp_token_get_sock(&init_net, msk->token));
+
+	/* this is now a no-op */
+	mptcp_token_destroy_request((struct request_sock *)req);
+	KUNIT_EXPECT_PTR_EQ(test, msk, mptcp_token_get_sock(&init_net, msk->token));
+
+	/* cleanup */
+	mptcp_token_destroy(msk);
+}
+
+static void mptcp_token_test_destroyed(struct kunit *test)
+{
+	struct mptcp_subflow_request_sock *req = build_req_sock(test);
+	struct mptcp_sock *msk = build_msk(test);
+	struct mptcp_sock *null_msk = NULL;
+	struct sock *sk;
+
+	sk = (struct sock *)msk;
+
+	KUNIT_ASSERT_EQ(test, 0,
+			mptcp_token_new_request((struct request_sock *)req));
+	msk->token = req->token;
+	mptcp_token_accept(req, msk);
+
+	/* simulate race on removal */
+	refcount_set(&sk->sk_refcnt, 0);
+	KUNIT_EXPECT_PTR_EQ(test, null_msk, mptcp_token_get_sock(&init_net, msk->token));
+
+	/* cleanup */
+	mptcp_token_destroy(msk);
+}
+
+static struct kunit_case mptcp_token_test_cases[] = {
+	KUNIT_CASE(mptcp_token_test_req_basic),
+	KUNIT_CASE(mptcp_token_test_msk_basic),
+	KUNIT_CASE(mptcp_token_test_accept),
+	KUNIT_CASE(mptcp_token_test_destroyed),
+	{}
+};
+
+static struct kunit_suite mptcp_token_suite = {
+	.name = "mptcp-token",
+	.test_cases = mptcp_token_test_cases,
+};
+
+kunit_test_suite(mptcp_token_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KUnit tests for MPTCP Token");