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, 46 insertions, 0 deletions

diff --git a/include/asm-generic/fprobe.h b/include/asm-generic/fprobe.h
new file mode 100644
index 000000000..8659a4dc6
--- /dev/null
+++ b/include/asm-generic/fprobe.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Generic arch dependent fprobe macros.
+ */
+#ifndef __ASM_GENERIC_FPROBE_H__
+#define __ASM_GENERIC_FPROBE_H__
+
+#include <linux/bits.h>
+
+#ifdef CONFIG_64BIT
+/*
+ * Encoding the size and the address of fprobe into one 64bit entry.
+ * The 32bit architectures should use 2 entries to store those info.
+ */
+
+#define ARCH_DEFINE_ENCODE_FPROBE_HEADER
+
+#define FPROBE_HEADER_MSB_SIZE_SHIFT (BITS_PER_LONG - FPROBE_DATA_SIZE_BITS)
+#define FPROBE_HEADER_MSB_MASK					\
+	GENMASK(FPROBE_HEADER_MSB_SIZE_SHIFT - 1, 0)
+
+/*
+ * By default, this expects the MSBs in the address of kprobe is 0xf.
+ * If any arch needs another fixed pattern (e.g. s390 is zero filled),
+ * override this.
+ */
+#define FPROBE_HEADER_MSB_PATTERN				\
+	GENMASK(BITS_PER_LONG - 1, FPROBE_HEADER_MSB_SIZE_SHIFT)
+
+#define arch_fprobe_header_encodable(fp)			\
+	(((unsigned long)(fp) & ~FPROBE_HEADER_MSB_MASK) ==	\
+	 FPROBE_HEADER_MSB_PATTERN)
+
+#define arch_encode_fprobe_header(fp, size)			\
+	(((unsigned long)(fp) & FPROBE_HEADER_MSB_MASK) |	\
+	 ((unsigned long)(size) << FPROBE_HEADER_MSB_SIZE_SHIFT))
+
+#define arch_decode_fprobe_header_size(val)			\
+	((unsigned long)(val) >> FPROBE_HEADER_MSB_SIZE_SHIFT)
+
+#define arch_decode_fprobe_header_fp(val)					\
+	((struct fprobe *)(((unsigned long)(val) & FPROBE_HEADER_MSB_MASK) |	\
+			   FPROBE_HEADER_MSB_PATTERN))
+#endif /* CONFIG_64BIT */
+
+#endif /* __ASM_GENERIC_FPROBE_H__ */