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, 120 insertions, 0 deletions

diff --git a/fs/ntfs/bdev-io.c b/fs/ntfs/bdev-io.c
new file mode 100644
index 000000000..86db4d929
--- /dev/null
+++ b/fs/ntfs/bdev-io.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * NTFS block device I/O.
+ *
+ * Copyright (c) 2026 LG Electronics Co., Ltd.
+ */
+
+#include <linux/blkdev.h>
+
+#include "ntfs.h"
+
+/*
+ * ntfs_bdev_read - Read data directly from block device using bio
+ * @bdev:	block device to read from
+ * @data:	destination buffer
+ * @start:	starting byte offset on the block device
+ * @size:	number of bytes to read
+ *
+ * Reads @size bytes starting from byte offset @start directly from the block
+ * device using one or more BIOs. This function bypasses the page cache
+ * completely and performs synchronous I/O with REQ_META | REQ_SYNC flags set.
+ *
+ * The @start offset must be sector-aligned (512 bytes). If it is not aligned,
+ * the function will return -EINVAL.
+ *
+ * If the destination buffer @data is not a vmalloc address, it falls back
+ * to the more efficient bdev_rw_virt() helper.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int ntfs_bdev_read(struct block_device *bdev, char *data, loff_t start, size_t size)
+{
+	unsigned int done = 0, added;
+	int error;
+	struct bio *bio;
+	blk_opf_t op;
+	sector_t sector = start >> SECTOR_SHIFT;
+
+	if (start & (SECTOR_SIZE - 1))
+		return -EINVAL;
+
+	op = REQ_OP_READ | REQ_META | REQ_SYNC;
+	if (!is_vmalloc_addr(data))
+		return bdev_rw_virt(bdev, sector, data, size, op);
+
+	bio = bio_alloc(bdev,
+			bio_max_segs(DIV_ROUND_UP(size, PAGE_SIZE)),
+			op, GFP_KERNEL);
+	bio->bi_iter.bi_sector = sector;
+
+	do {
+		added = bio_add_vmalloc_chunk(bio, data + done, size - done);
+		if (!added) {
+			struct bio	*prev = bio;
+
+			bio = bio_alloc(prev->bi_bdev,
+					bio_max_segs(DIV_ROUND_UP(size - done, PAGE_SIZE)),
+					prev->bi_opf, GFP_KERNEL);
+			bio->bi_iter.bi_sector = bio_end_sector(prev);
+			bio_chain(prev, bio);
+			submit_bio(prev);
+		}
+		done += added;
+	} while (done < size);
+
+	error = submit_bio_wait(bio);
+	bio_put(bio);
+
+	if ((op & REQ_OP_MASK) == REQ_OP_READ)
+		invalidate_kernel_vmap_range(data, size);
+	return error;
+}
+
+/*
+ * ntfs_bdev_write - Update block device contents via page cache
+ * @sb:		super block of the mounted NTFS filesystem
+ * @buf:	source buffer containing data to write
+ * @start:	starting byte offset on the block device
+ * @size:	number of bytes to write
+ *
+ * Writes @size bytes from @buf to the block device (sb->s_bdev) starting
+ * at byte offset @start. The write is performed entirely through the page
+ * cache of the block device's address space.
+ */
+int ntfs_bdev_write(struct super_block *sb, void *buf, loff_t start, size_t size)
+{
+	pgoff_t idx, idx_end;
+	loff_t offset, end = start + size;
+	u32 from, to, buf_off = 0;
+	struct folio *folio;
+
+	idx = start >> PAGE_SHIFT;
+	idx_end = end >> PAGE_SHIFT;
+	from = start & ~PAGE_MASK;
+
+	if (idx == idx_end)
+		idx_end++;
+
+	for (; idx < idx_end; idx++, from = 0) {
+		u32 len;
+
+		folio = read_mapping_folio(sb->s_bdev->bd_mapping, idx, NULL);
+		if (IS_ERR(folio)) {
+			ntfs_error(sb, "Unable to read %ld page", idx);
+			return PTR_ERR(folio);
+		}
+
+		offset = (loff_t)idx << PAGE_SHIFT;
+		to = min_t(u32, end - offset, PAGE_SIZE);
+		len = to - from;
+
+		memcpy_to_folio(folio, from, buf + buf_off, len);
+		buf_off += len;
+		folio_mark_uptodate(folio);
+		folio_mark_dirty(folio);
+		folio_put(folio);
+	}
+
+	return 0;
+}