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, 143 insertions, 0 deletions

diff --git a/net/sunrpc/auth_null.c b/net/sunrpc/auth_null.c
new file mode 100644
index 000000000..41a633a40
--- /dev/null
+++ b/net/sunrpc/auth_null.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/net/sunrpc/auth_null.c
+ *
+ * AUTH_NULL authentication. Really :-)
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/sunrpc/clnt.h>
+
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+# define RPCDBG_FACILITY	RPCDBG_AUTH
+#endif
+
+static struct rpc_auth null_auth;
+static struct rpc_cred null_cred;
+
+static struct rpc_auth *
+nul_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
+{
+	refcount_inc(&null_auth.au_count);
+	return &null_auth;
+}
+
+static void
+nul_destroy(struct rpc_auth *auth)
+{
+}
+
+/*
+ * Lookup NULL creds for current process
+ */
+static struct rpc_cred *
+nul_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
+{
+	return get_rpccred(&null_cred);
+}
+
+/*
+ * Destroy cred handle.
+ */
+static void
+nul_destroy_cred(struct rpc_cred *cred)
+{
+}
+
+/*
+ * Match cred handle against current process
+ */
+static int
+nul_match(struct auth_cred *acred, struct rpc_cred *cred, int taskflags)
+{
+	return 1;
+}
+
+/*
+ * Marshal credential.
+ */
+static int
+nul_marshal(struct rpc_task *task, struct xdr_stream *xdr)
+{
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 4 * sizeof(*p));
+	if (!p)
+		return -EMSGSIZE;
+	/* Credential */
+	*p++ = rpc_auth_null;
+	*p++ = xdr_zero;
+	/* Verifier */
+	*p++ = rpc_auth_null;
+	*p   = xdr_zero;
+	return 0;
+}
+
+/*
+ * Refresh credential. This is a no-op for AUTH_NULL
+ */
+static int
+nul_refresh(struct rpc_task *task)
+{
+	set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
+	return 0;
+}
+
+static int
+nul_validate(struct rpc_task *task, struct xdr_stream *xdr)
+{
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 2 * sizeof(*p));
+	if (!p)
+		return -EIO;
+	if (*p++ != rpc_auth_null)
+		return -EIO;
+	if (*p != xdr_zero)
+		return -EIO;
+	return 0;
+}
+
+const struct rpc_authops authnull_ops = {
+	.owner		= THIS_MODULE,
+	.au_flavor	= RPC_AUTH_NULL,
+	.au_name	= "NULL",
+	.create		= nul_create,
+	.destroy	= nul_destroy,
+	.lookup_cred	= nul_lookup_cred,
+};
+
+static
+struct rpc_auth null_auth = {
+	.au_cslack	= NUL_CALLSLACK,
+	.au_rslack	= NUL_REPLYSLACK,
+	.au_verfsize	= NUL_REPLYSLACK,
+	.au_ralign	= NUL_REPLYSLACK,
+	.au_ops		= &authnull_ops,
+	.au_flavor	= RPC_AUTH_NULL,
+	.au_count	= REFCOUNT_INIT(1),
+};
+
+static
+const struct rpc_credops null_credops = {
+	.cr_name	= "AUTH_NULL",
+	.crdestroy	= nul_destroy_cred,
+	.crmatch	= nul_match,
+	.crmarshal	= nul_marshal,
+	.crwrap_req	= rpcauth_wrap_req_encode,
+	.crrefresh	= nul_refresh,
+	.crvalidate	= nul_validate,
+	.crunwrap_resp	= rpcauth_unwrap_resp_decode,
+};
+
+static
+struct rpc_cred null_cred = {
+	.cr_lru		= LIST_HEAD_INIT(null_cred.cr_lru),
+	.cr_auth	= &null_auth,
+	.cr_ops		= &null_credops,
+	.cr_count	= REFCOUNT_INIT(2),
+	.cr_flags	= 1UL << RPCAUTH_CRED_UPTODATE,
+};