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, 58 insertions, 0 deletions

diff --git a/tools/build/Makefile b/tools/build/Makefile
new file mode 100644
index 000000000..3a5a3808a
--- /dev/null
+++ b/tools/build/Makefile
@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: GPL-2.0
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+include $(srctree)/tools//scripts/Makefile.include
+
+define allow-override
+  $(if $(or $(findstring environment,$(origin $(1))),\
+            $(findstring command line,$(origin $(1)))),,\
+    $(eval $(1) = $(2)))
+endef
+
+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+$(call allow-override,LD,$(CROSS_COMPILE)ld)
+
+export HOSTCC HOSTLD HOSTAR
+
+export srctree CC LD
+
+MAKEFLAGS := --no-print-directory
+build     := -f $(srctree)/tools/build/Makefile.build dir=. obj
+
+all: $(OUTPUT)fixdep
+
+# Make sure there's anything to clean,
+# feature contains check for existing OUTPUT
+TMP_O := $(if $(OUTPUT),$(OUTPUT)feature/,./)
+
+clean:
+	$(call QUIET_CLEAN, fixdep)
+	$(Q)find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
+	$(Q)rm -f $(OUTPUT)fixdep
+	$(call QUIET_CLEAN, feature-detect)
+ifneq ($(wildcard $(TMP_O)),)
+	$(Q)$(MAKE) -C feature OUTPUT=$(TMP_O) clean >/dev/null
+endif
+
+FIXDEP		:= $(OUTPUT)fixdep
+FIXDEP_IN	:= $(OUTPUT)fixdep-in.o
+
+# To track fixdep's dependencies properly, fixdep needs to run on itself.
+# Build it twice the first time.
+$(FIXDEP_IN): FORCE
+	$(Q)if [ ! -f $(FIXDEP) ]; then						\
+		$(MAKE) $(build)=fixdep HOSTCFLAGS="$(KBUILD_HOSTCFLAGS)";	\
+		rm -f $(FIXDEP).o;						\
+	fi
+	$(Q)$(MAKE) $(build)=fixdep HOSTCFLAGS="$(KBUILD_HOSTCFLAGS)"
+
+
+$(FIXDEP): $(FIXDEP_IN)
+	$(QUIET_LINK)$(HOSTCC) $(FIXDEP_IN) $(KBUILD_HOSTLDFLAGS) -o $@
+
+FORCE:
+
+.PHONY: FORCE