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, 27 insertions, 0 deletions

diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
new file mode 100644
index 000000000..c729bc936
--- /dev/null
+++ b/scripts/mod/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS_REMOVE_empty.o += $(CC_FLAGS_LTO)
+
+hostprogs-always-y	+= modpost mk_elfconfig
+always-y		+= empty.o
+
+modpost-objs	:= modpost.o file2alias.o sumversion.o symsearch.o
+
+devicetable-offsets-file := devicetable-offsets.h
+
+$(obj)/$(devicetable-offsets-file): $(obj)/devicetable-offsets.s FORCE
+	$(call filechk,offsets,__DEVICETABLE_OFFSETS_H__)
+
+targets += $(devicetable-offsets-file) devicetable-offsets.s
+
+# dependencies on generated files need to be listed explicitly
+
+$(obj)/modpost.o $(obj)/file2alias.o $(obj)/sumversion.o $(obj)/symsearch.o: $(obj)/elfconfig.h
+$(obj)/file2alias.o: $(obj)/$(devicetable-offsets-file)
+
+quiet_cmd_elfconfig = MKELF   $@
+      cmd_elfconfig = $(obj)/mk_elfconfig < $< > $@
+
+$(obj)/elfconfig.h: $(obj)/empty.o $(obj)/mk_elfconfig FORCE
+	$(call if_changed,elfconfig)
+
+targets += elfconfig.h