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, 114 insertions, 0 deletions

diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
new file mode 100644
index 000000000..58c7bb25e
--- /dev/null
+++ b/fs/notify/fsnotify.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __FS_NOTIFY_FSNOTIFY_H_
+#define __FS_NOTIFY_FSNOTIFY_H_
+
+#include <linux/list.h>
+#include <linux/fsnotify.h>
+#include <linux/srcu.h>
+#include <linux/types.h>
+
+#include "../mount.h"
+
+/*
+ * fsnotify_connp_t is what we embed in objects which connector can be attached
+ * to.
+ */
+typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;
+
+static inline struct inode *fsnotify_conn_inode(
+				struct fsnotify_mark_connector *conn)
+{
+	return conn->obj;
+}
+
+static inline struct mount *fsnotify_conn_mount(
+				struct fsnotify_mark_connector *conn)
+{
+	return real_mount(conn->obj);
+}
+
+static inline struct super_block *fsnotify_conn_sb(
+				struct fsnotify_mark_connector *conn)
+{
+	return conn->obj;
+}
+
+static inline struct mnt_namespace *fsnotify_conn_mntns(
+				struct fsnotify_mark_connector *conn)
+{
+	return conn->obj;
+}
+
+static inline struct super_block *fsnotify_object_sb(void *obj,
+			enum fsnotify_obj_type obj_type)
+{
+	switch (obj_type) {
+	case FSNOTIFY_OBJ_TYPE_INODE:
+		return ((struct inode *)obj)->i_sb;
+	case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
+		return ((struct vfsmount *)obj)->mnt_sb;
+	case FSNOTIFY_OBJ_TYPE_SB:
+		return (struct super_block *)obj;
+	default:
+		return NULL;
+	}
+}
+
+static inline struct super_block *fsnotify_connector_sb(
+				struct fsnotify_mark_connector *conn)
+{
+	return fsnotify_object_sb(conn->obj, conn->type);
+}
+
+static inline fsnotify_connp_t *fsnotify_sb_marks(struct super_block *sb)
+{
+	struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb);
+
+	return sbinfo ? &sbinfo->sb_marks : NULL;
+}
+
+/* destroy all events sitting in this groups notification queue */
+extern void fsnotify_flush_notify(struct fsnotify_group *group);
+
+/* protects reads of inode and vfsmount marks list */
+extern struct srcu_struct fsnotify_mark_srcu;
+
+/* compare two groups for sorting of marks lists */
+extern int fsnotify_compare_groups(struct fsnotify_group *a,
+				   struct fsnotify_group *b);
+
+/* Destroy all inode marks for given superblock */
+void fsnotify_unmount_inodes(struct fsnotify_sb_info *sbinfo);
+
+/* Destroy all marks attached to an object via connector */
+extern void fsnotify_destroy_marks(fsnotify_connp_t *connp);
+/* run the list of all marks associated with inode and destroy them */
+static inline void fsnotify_clear_marks_by_inode(struct inode *inode)
+{
+	fsnotify_destroy_marks(&inode->i_fsnotify_marks);
+}
+/* run the list of all marks associated with vfsmount and destroy them */
+static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
+{
+	fsnotify_destroy_marks(&real_mount(mnt)->mnt_fsnotify_marks);
+}
+/* run the list of all marks associated with sb and destroy them */
+static inline void fsnotify_clear_marks_by_sb(struct super_block *sb)
+{
+	fsnotify_destroy_marks(fsnotify_sb_marks(sb));
+}
+
+static inline void fsnotify_clear_marks_by_mntns(struct mnt_namespace *mntns)
+{
+	fsnotify_destroy_marks(&mntns->n_fsnotify_marks);
+}
+
+/*
+ * update the dentry->d_flags of all of inode's children to indicate if inode cares
+ * about events that happen to its children.
+ */
+extern void fsnotify_set_children_dentry_flags(struct inode *inode);
+
+void fsnotify_init_connector_caches(void);
+
+#endif	/* __FS_NOTIFY_FSNOTIFY_H_ */