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, 37 insertions, 0 deletions

diff --git a/net/ethtool/bitset.h b/net/ethtool/bitset.h
new file mode 100644
index 000000000..07bc547d4
--- /dev/null
+++ b/net/ethtool/bitset.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _NET_ETHTOOL_BITSET_H
+#define _NET_ETHTOOL_BITSET_H
+
+#include <linux/ethtool.h>
+#include <linux/netlink.h>
+
+#define ETHNL_MAX_BITSET_SIZE S16_MAX
+
+typedef const char (*const ethnl_string_array_t)[ETH_GSTRING_LEN];
+
+int ethnl_bitset_is_compact(const struct nlattr *bitset, bool *compact);
+int ethnl_bitset_size(const unsigned long *val, const unsigned long *mask,
+		      unsigned int nbits, ethnl_string_array_t names,
+		      bool compact);
+int ethnl_bitset32_size(const u32 *val, const u32 *mask, unsigned int nbits,
+			ethnl_string_array_t names, bool compact);
+int ethnl_put_bitset(struct sk_buff *skb, int attrtype,
+		     const unsigned long *val, const unsigned long *mask,
+		     unsigned int nbits, ethnl_string_array_t names,
+		     bool compact);
+int ethnl_put_bitset32(struct sk_buff *skb, int attrtype, const u32 *val,
+		       const u32 *mask, unsigned int nbits,
+		       ethnl_string_array_t names, bool compact);
+int ethnl_update_bitset(unsigned long *bitmap, unsigned int nbits,
+			const struct nlattr *attr, ethnl_string_array_t names,
+			struct netlink_ext_ack *extack, bool *mod);
+int ethnl_update_bitset32(u32 *bitmap, unsigned int nbits,
+			  const struct nlattr *attr, ethnl_string_array_t names,
+			  struct netlink_ext_ack *extack, bool *mod);
+int ethnl_parse_bitset(unsigned long *val, unsigned long *mask,
+		       unsigned int nbits, const struct nlattr *attr,
+		       ethnl_string_array_t names,
+		       struct netlink_ext_ack *extack);
+
+#endif /* _NET_ETHTOOL_BITSET_H */