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, 94 insertions, 0 deletions

diff --git a/net/ceph/msgpool.c b/net/ceph/msgpool.c
new file mode 100644
index 000000000..e3ecb80cd
--- /dev/null
+++ b/net/ceph/msgpool.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+
+#include <linux/ceph/messenger.h>
+#include <linux/ceph/msgpool.h>
+
+static void *msgpool_alloc(gfp_t gfp_mask, void *arg)
+{
+	struct ceph_msgpool *pool = arg;
+	struct ceph_msg *msg;
+
+	msg = ceph_msg_new2(pool->type, pool->front_len, pool->max_data_items,
+			    gfp_mask, true);
+	if (!msg) {
+		dout("msgpool_alloc %s failed\n", pool->name);
+	} else {
+		dout("msgpool_alloc %s %p\n", pool->name, msg);
+		msg->pool = pool;
+	}
+	return msg;
+}
+
+static void msgpool_free(void *element, void *arg)
+{
+	struct ceph_msgpool *pool = arg;
+	struct ceph_msg *msg = element;
+
+	dout("msgpool_release %s %p\n", pool->name, msg);
+	msg->pool = NULL;
+	ceph_msg_put(msg);
+}
+
+int ceph_msgpool_init(struct ceph_msgpool *pool, int type,
+		      int front_len, int max_data_items, int size,
+		      const char *name)
+{
+	dout("msgpool %s init\n", name);
+	pool->type = type;
+	pool->front_len = front_len;
+	pool->max_data_items = max_data_items;
+	pool->pool = mempool_create(size, msgpool_alloc, msgpool_free, pool);
+	if (!pool->pool)
+		return -ENOMEM;
+	pool->name = name;
+	return 0;
+}
+
+void ceph_msgpool_destroy(struct ceph_msgpool *pool)
+{
+	dout("msgpool %s destroy\n", pool->name);
+	mempool_destroy(pool->pool);
+}
+
+struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, int front_len,
+				  int max_data_items)
+{
+	struct ceph_msg *msg;
+
+	if (front_len > pool->front_len ||
+	    max_data_items > pool->max_data_items) {
+		pr_warn_ratelimited("%s need %d/%d, pool %s has %d/%d\n",
+		    __func__, front_len, max_data_items, pool->name,
+		    pool->front_len, pool->max_data_items);
+		WARN_ON_ONCE(1);
+
+		/* try to alloc a fresh message */
+		return ceph_msg_new2(pool->type, front_len, max_data_items,
+				     GFP_NOFS, false);
+	}
+
+	msg = mempool_alloc(pool->pool, GFP_NOFS);
+	dout("msgpool_get %s %p\n", pool->name, msg);
+	return msg;
+}
+
+void ceph_msgpool_put(struct ceph_msgpool *pool, struct ceph_msg *msg)
+{
+	dout("msgpool_put %s %p\n", pool->name, msg);
+
+	/* reset msg front_len; user may have changed it */
+	msg->front.iov_len = pool->front_len;
+	msg->hdr.front_len = cpu_to_le32(pool->front_len);
+
+	msg->data_length = 0;
+	msg->num_data_items = 0;
+
+	kref_init(&msg->kref);  /* retake single ref */
+	mempool_free(msg, pool->pool);
+}