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, 19 insertions, 0 deletions

diff --git a/scripts/kconfig/preprocess.h b/scripts/kconfig/preprocess.h
new file mode 100644
index 000000000..a7e4a5506
--- /dev/null
+++ b/scripts/kconfig/preprocess.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef PREPROCESS_H
+#define PREPROCESS_H
+
+enum variable_flavor {
+	VAR_SIMPLE,
+	VAR_RECURSIVE,
+	VAR_APPEND,
+};
+
+struct gstr;
+void env_write_dep(struct gstr *gs);
+void variable_add(const char *name, const char *value,
+		  enum variable_flavor flavor);
+void variable_all_del(void);
+char *expand_dollar(const char **str);
+char *expand_one_token(const char **str);
+
+#endif /* PREPROCESS_H */