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, 42 insertions, 0 deletions

diff --git a/scripts/coccinelle/misc/cstptr.cocci b/scripts/coccinelle/misc/cstptr.cocci
new file mode 100644
index 000000000..74acf34be
--- /dev/null
+++ b/scripts/coccinelle/misc/cstptr.cocci
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/// PTR_ERR should be applied before its argument is reassigned, typically
+/// to NULL
+///
+// Confidence: High
+// Copyright: (C) 2012 Julia Lawall, INRIA/LIP6.
+// Copyright: (C) 2012 Gilles Muller, INRIA/LiP6.
+// URL: https://coccinelle.gitlabpages.inria.fr/website
+// Comments:
+// Options: --no-includes --include-headers
+
+virtual org
+virtual report
+virtual context
+
+@r exists@
+expression e,e1;
+constant c;
+position p1,p2;
+@@
+
+*e@p1 = c
+... when != e = e1
+    when != &e
+    when != true IS_ERR(e)
+*PTR_ERR@p2(e)
+
+@script:python depends on org@
+p1 << r.p1;
+p2 << r.p2;
+@@
+
+cocci.print_main("PTR_ERR",p2)
+cocci.print_secs("assignment",p1)
+
+@script:python depends on report@
+p1 << r.p1;
+p2 << r.p2;
+@@
+
+msg = "ERROR: PTR_ERR applied after initialization to constant on line %s" % (p1[0].line)
+coccilib.report.print_report(p2[0],msg)