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, 47 insertions, 0 deletions

diff --git a/include/sound/ump_convert.h b/include/sound/ump_convert.h
new file mode 100644
index 000000000..682499b87
--- /dev/null
+++ b/include/sound/ump_convert.h
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#ifndef __SOUND_UMP_CONVERT_H
+#define __SOUND_UMP_CONVERT_H
+
+#include <sound/ump_msg.h>
+
+/* context for converting from legacy control messages to UMP packet */
+struct ump_cvt_to_ump_bank {
+	bool rpn_set;
+	bool nrpn_set;
+	bool bank_set;
+	unsigned char cc_rpn_msb, cc_rpn_lsb;
+	unsigned char cc_nrpn_msb, cc_nrpn_lsb;
+	unsigned char cc_data_msb, cc_data_lsb;
+	unsigned char cc_bank_msb, cc_bank_lsb;
+	bool cc_data_msb_set, cc_data_lsb_set;
+};
+
+/* context for converting from MIDI1 byte stream to UMP packet */
+struct ump_cvt_to_ump {
+	/* MIDI1 intermediate buffer */
+	unsigned char buf[6]; /* up to 6 bytes for SysEx */
+	int len;
+	int cmd_bytes;
+
+	/* UMP output packet */
+	u32 ump[4];
+	int ump_bytes;
+
+	/* various status */
+	unsigned int in_sysex;
+	struct ump_cvt_to_ump_bank bank[16];	/* per channel */
+};
+
+int snd_ump_convert_from_ump(const u32 *data, unsigned char *dst,
+			     unsigned char *group_ret);
+void snd_ump_convert_to_ump(struct ump_cvt_to_ump *cvt, unsigned char group,
+			    unsigned int protocol, unsigned char c);
+
+/* reset the converter context, called at each open to ump */
+static inline void snd_ump_convert_reset(struct ump_cvt_to_ump *ctx)
+{
+	memset(ctx, 0, sizeof(*ctx));
+
+}
+
+#endif /* __SOUND_UMP_CONVERT_H */