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, 141 insertions, 0 deletions

diff --git a/io_uring/notif.c b/io_uring/notif.c
new file mode 100644
index 000000000..efce8ae12
--- /dev/null
+++ b/io_uring/notif.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/net.h>
+#include <linux/io_uring.h>
+
+#include "io_uring.h"
+#include "notif.h"
+#include "rsrc.h"
+
+static const struct ubuf_info_ops io_ubuf_ops;
+
+static void io_notif_tw_complete(struct io_tw_req tw_req, io_tw_token_t tw)
+{
+	struct io_kiocb *notif = tw_req.req;
+	struct io_notif_data *nd = io_notif_to_data(notif);
+	struct io_ring_ctx *ctx = notif->ctx;
+
+	lockdep_assert_held(&ctx->uring_lock);
+
+	do {
+		notif = cmd_to_io_kiocb(nd);
+
+		if (WARN_ON_ONCE(ctx != notif->ctx))
+			return;
+		lockdep_assert(refcount_read(&nd->uarg.refcnt) == 0);
+
+		if (unlikely(nd->zc_report) && (nd->zc_copied || !nd->zc_used))
+			notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED;
+
+		if (nd->account_pages && notif->ctx->user) {
+			__io_unaccount_mem(notif->ctx->user, nd->account_pages);
+			nd->account_pages = 0;
+		}
+
+		nd = nd->next;
+		io_req_task_complete((struct io_tw_req){notif}, tw);
+	} while (nd);
+}
+
+void io_tx_ubuf_complete(struct sk_buff *skb, struct ubuf_info *uarg,
+			 bool success)
+{
+	struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);
+	struct io_kiocb *notif = cmd_to_io_kiocb(nd);
+	unsigned tw_flags;
+
+	if (nd->zc_report) {
+		if (success && !nd->zc_used && skb)
+			WRITE_ONCE(nd->zc_used, true);
+		else if (!success && !nd->zc_copied)
+			WRITE_ONCE(nd->zc_copied, true);
+	}
+
+	if (!refcount_dec_and_test(&uarg->refcnt))
+		return;
+
+	if (nd->head != nd) {
+		io_tx_ubuf_complete(skb, &nd->head->uarg, success);
+		return;
+	}
+
+	tw_flags = nd->next ? 0 : IOU_F_TWQ_LAZY_WAKE;
+	notif->io_task_work.func = io_notif_tw_complete;
+	__io_req_task_work_add(notif, tw_flags);
+}
+
+static int io_link_skb(struct sk_buff *skb, struct ubuf_info *uarg)
+{
+	struct io_notif_data *nd, *prev_nd;
+	struct io_kiocb *prev_notif, *notif;
+	struct ubuf_info *prev_uarg = skb_zcopy(skb);
+
+	nd = container_of(uarg, struct io_notif_data, uarg);
+	notif = cmd_to_io_kiocb(nd);
+
+	if (!prev_uarg) {
+		net_zcopy_get(&nd->uarg);
+		skb_zcopy_init(skb, &nd->uarg);
+		return 0;
+	}
+	/* handle it separately as we can't link a notif to itself */
+	if (unlikely(prev_uarg == &nd->uarg))
+		return 0;
+	/* we can't join two links together, just request a fresh skb */
+	if (unlikely(nd->head != nd || nd->next))
+		return -EEXIST;
+	/* don't mix zc providers */
+	if (unlikely(prev_uarg->ops != &io_ubuf_ops))
+		return -EEXIST;
+
+	prev_nd = container_of(prev_uarg, struct io_notif_data, uarg);
+	prev_notif = cmd_to_io_kiocb(prev_nd);
+
+	/* make sure all notifications can be finished in the same task_work */
+	if (unlikely(notif->ctx != prev_notif->ctx ||
+		     notif->tctx != prev_notif->tctx))
+		return -EEXIST;
+
+	nd->head = prev_nd->head;
+	nd->next = prev_nd->next;
+	prev_nd->next = nd;
+	net_zcopy_get(&nd->head->uarg);
+	return 0;
+}
+
+static const struct ubuf_info_ops io_ubuf_ops = {
+	.complete = io_tx_ubuf_complete,
+	.link_skb = io_link_skb,
+};
+
+struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
+	__must_hold(&ctx->uring_lock)
+{
+	struct io_kiocb *notif;
+	struct io_notif_data *nd;
+
+	if (unlikely(!io_alloc_req(ctx, &notif)))
+		return NULL;
+	notif->ctx = ctx;
+	notif->opcode = IORING_OP_NOP;
+	notif->flags = 0;
+	notif->file = NULL;
+	notif->tctx = current->io_uring;
+	io_get_task_refs(1);
+	notif->file_node = NULL;
+	notif->buf_node = NULL;
+
+	nd = io_notif_to_data(notif);
+	nd->zc_report = false;
+	nd->account_pages = 0;
+	nd->next = NULL;
+	nd->head = nd;
+
+	nd->uarg.flags = IO_NOTIF_UBUF_FLAGS;
+	nd->uarg.ops = &io_ubuf_ops;
+	refcount_set(&nd->uarg.refcnt, 1);
+	return notif;
+}