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, 24 insertions, 0 deletions

diff --git a/lib/kstrtox.h b/lib/kstrtox.h
new file mode 100644
index 000000000..73dee79fd
--- /dev/null
+++ b/lib/kstrtox.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIB_KSTRTOX_H
+#define _LIB_KSTRTOX_H
+
+#include <linux/args.h>
+
+#define KSTRTOX_OVERFLOW	(1U << 31)
+const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
+unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *res,
+				  size_t max_chars, unsigned long long init);
+
+#define _parse_integer0(s, base, res, ...)						\
+	_parse_integer_limit(s, base, res, INT_MAX, 0)
+
+#define _parse_integer1(s, base, res, max_chars, ...)					\
+	_parse_integer_limit(s, base, res, max_chars, 0)
+
+#define _parse_integer2(s, base, res, max_chars, init, ...)				\
+	_parse_integer_limit(s, base, res, max_chars, init)
+
+#define _parse_integer(s, base, res, ...)						\
+	CONCATENATE(_parse_integer, COUNT_ARGS(__VA_ARGS__))(s, base, res, __VA_ARGS__)
+
+#endif