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, 41 insertions, 0 deletions

diff --git a/fs/smb/server/unicode.h b/fs/smb/server/unicode.h
new file mode 100644
index 000000000..28c7c736f
--- /dev/null
+++ b/fs/smb/server/unicode.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Some of the source code in this file came from fs/cifs/cifs_unicode.c
+ * cifs_unicode:  Unicode kernel case support
+ *
+ * Function:
+ *     Convert a unicode character to upper or lower case using
+ *     compressed tables.
+ *
+ *   Copyright (c) International Business Machines  Corp., 2000,2009
+ *
+ *
+ * Notes:
+ *     These APIs are based on the C library functions.  The semantics
+ *     should match the C functions but with expanded size operands.
+ *
+ *     The upper/lower functions are based on a table created by mkupr.
+ *     This is a compressed table of upper and lower case conversion.
+ *
+ */
+#ifndef _SMB_UNICODE_H
+#define _SMB_UNICODE_H
+
+#include <asm/byteorder.h>
+#include <linux/types.h>
+#include <linux/nls.h>
+#include <linux/unicode.h>
+#include "../../nls/nls_ucs2_utils.h"
+
+#ifdef __KERNEL__
+int smb_strtoUTF16(__le16 *to, const char *from, int len,
+		   const struct nls_table *codepage);
+char *smb_strndup_from_utf16(const char *src, const int maxlen,
+			     const bool is_unicode,
+			     const struct nls_table *codepage);
+int smbConvertToUTF16(__le16 *target, const char *source, int srclen,
+		      const struct nls_table *cp, int mapchars);
+char *ksmbd_extract_sharename(struct unicode_map *um, const char *treename);
+#endif
+
+#endif /* _SMB_UNICODE_H */