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, 76 insertions, 0 deletions

diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c
new file mode 100644
index 000000000..d95b6d0d9
--- /dev/null
+++ b/net/xdp/xsk_queue.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/* XDP user-space ring structure
+ * Copyright(c) 2018 Intel Corporation.
+ */
+
+#include <linux/log2.h>
+#include <linux/slab.h>
+#include <linux/overflow.h>
+#include <linux/vmalloc.h>
+#include <net/xdp_sock_drv.h>
+
+#include <asm/shmparam.h>
+
+#include "xsk_queue.h"
+
+static size_t xskq_get_ring_size(struct xsk_queue *q, bool umem_queue)
+{
+	struct xdp_umem_ring *umem_ring;
+	struct xdp_rxtx_ring *rxtx_ring;
+
+	if (umem_queue)
+		return struct_size(umem_ring, desc, q->nentries);
+	return struct_size(rxtx_ring, desc, q->nentries);
+}
+
+static void *xskq_vmalloc_user(unsigned long size)
+{
+	return __vmalloc_node_range(size, SHMLBA, VMALLOC_START, VMALLOC_END,
+				     GFP_KERNEL_ACCOUNT | __GFP_ZERO, PAGE_KERNEL,
+				     VM_USERMAP, NUMA_NO_NODE,
+				     __builtin_return_address(0));
+}
+
+struct xsk_queue *xskq_create(u32 nentries, bool umem_queue)
+{
+	struct xsk_queue *q;
+	size_t size;
+
+	q = kzalloc_obj(*q);
+	if (!q)
+		return NULL;
+
+	q->nentries = nentries;
+	q->ring_mask = nentries - 1;
+
+	size = xskq_get_ring_size(q, umem_queue);
+
+	/* size which is overflowing or close to SIZE_MAX will become 0 in
+	 * PAGE_ALIGN(), checking SIZE_MAX is enough due to the previous
+	 * is_power_of_2(), the rest will be handled by vmalloc_user()
+	 */
+	if (unlikely(size == SIZE_MAX)) {
+		kfree(q);
+		return NULL;
+	}
+
+	size = PAGE_ALIGN(size);
+
+	q->ring = xskq_vmalloc_user(size);
+	if (!q->ring) {
+		kfree(q);
+		return NULL;
+	}
+
+	q->ring_vmalloc_size = size;
+	return q;
+}
+
+void xskq_destroy(struct xsk_queue *q)
+{
+	if (!q)
+		return;
+
+	vfree(q->ring);
+	kfree(q);
+}