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, 62 insertions, 0 deletions

diff --git a/fs/hpfs/dentry.c b/fs/hpfs/dentry.c
new file mode 100644
index 000000000..89a36fdc6
--- /dev/null
+++ b/fs/hpfs/dentry.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/hpfs/dentry.c
+ *
+ *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
+ *
+ *  dcache operations
+ */
+
+#include "hpfs_fn.h"
+
+/*
+ * Note: the dentry argument is the parent dentry.
+ */
+
+static int hpfs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
+{
+	unsigned long	 hash;
+	int		 i;
+	unsigned l = qstr->len;
+
+	if (l == 1) if (qstr->name[0]=='.') goto x;
+	if (l == 2) if (qstr->name[0]=='.' || qstr->name[1]=='.') goto x;
+	hpfs_adjust_length(qstr->name, &l);
+	/*if (hpfs_chk_name(qstr->name,&l))*/
+		/*return -ENAMETOOLONG;*/
+		/*return -ENOENT;*/
+	x:
+
+	hash = init_name_hash(dentry);
+	for (i = 0; i < l; i++)
+		hash = partial_name_hash(hpfs_upcase(hpfs_sb(dentry->d_sb)->sb_cp_table,qstr->name[i]), hash);
+	qstr->hash = end_name_hash(hash);
+
+	return 0;
+}
+
+static int hpfs_compare_dentry(const struct dentry *dentry,
+		unsigned int len, const char *str, const struct qstr *name)
+{
+	unsigned al = len;
+	unsigned bl = name->len;
+
+	hpfs_adjust_length(str, &al);
+	/*hpfs_adjust_length(b->name, &bl);*/
+
+	/*
+	 * 'str' is the nane of an already existing dentry, so the name
+	 * must be valid. 'name' must be validated first.
+	 */
+
+	if (hpfs_chk_name(name->name, &bl))
+		return 1;
+	if (hpfs_compare_names(dentry->d_sb, str, al, name->name, bl, 0))
+		return 1;
+	return 0;
+}
+
+const struct dentry_operations hpfs_dentry_operations = {
+	.d_hash		= hpfs_hash_dentry,
+	.d_compare	= hpfs_compare_dentry,
+};