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, 232 insertions, 0 deletions

diff --git a/lib/fw_table.c b/lib/fw_table.c
new file mode 100644
index 000000000..162918144
--- /dev/null
+++ b/lib/fw_table.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  fw_tables.c - Parsing support for ACPI and ACPI-like tables provided by
+ *                platform or device firmware
+ *
+ *  Copyright (C) 2001 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2023 Intel Corp.
+ */
+#include <linux/errno.h>
+#include <linux/acpi.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/fw_table.h>
+
+enum acpi_subtable_type {
+	ACPI_SUBTABLE_COMMON,
+	ACPI_SUBTABLE_HMAT,
+	ACPI_SUBTABLE_PRMT,
+	ACPI_SUBTABLE_CEDT,
+	CDAT_SUBTABLE,
+};
+
+struct acpi_subtable_entry {
+	union acpi_subtable_headers *hdr;
+	enum acpi_subtable_type type;
+};
+
+static unsigned long __init_or_fwtbl_lib
+acpi_get_entry_type(struct acpi_subtable_entry *entry)
+{
+	switch (entry->type) {
+	case ACPI_SUBTABLE_COMMON:
+		return entry->hdr->common.type;
+	case ACPI_SUBTABLE_HMAT:
+		return entry->hdr->hmat.type;
+	case ACPI_SUBTABLE_PRMT:
+		return 0;
+	case ACPI_SUBTABLE_CEDT:
+		return entry->hdr->cedt.type;
+	case CDAT_SUBTABLE:
+		return entry->hdr->cdat.type;
+	}
+	return 0;
+}
+
+static unsigned long __init_or_fwtbl_lib
+acpi_get_entry_length(struct acpi_subtable_entry *entry)
+{
+	switch (entry->type) {
+	case ACPI_SUBTABLE_COMMON:
+		return entry->hdr->common.length;
+	case ACPI_SUBTABLE_HMAT:
+		return entry->hdr->hmat.length;
+	case ACPI_SUBTABLE_PRMT:
+		return entry->hdr->prmt.length;
+	case ACPI_SUBTABLE_CEDT:
+		return entry->hdr->cedt.length;
+	case CDAT_SUBTABLE: {
+		__le16 length = (__force __le16)entry->hdr->cdat.length;
+
+		return le16_to_cpu(length);
+	}
+	}
+	return 0;
+}
+
+static unsigned long __init_or_fwtbl_lib
+acpi_get_subtable_header_length(struct acpi_subtable_entry *entry)
+{
+	switch (entry->type) {
+	case ACPI_SUBTABLE_COMMON:
+		return sizeof(entry->hdr->common);
+	case ACPI_SUBTABLE_HMAT:
+		return sizeof(entry->hdr->hmat);
+	case ACPI_SUBTABLE_PRMT:
+		return sizeof(entry->hdr->prmt);
+	case ACPI_SUBTABLE_CEDT:
+		return sizeof(entry->hdr->cedt);
+	case CDAT_SUBTABLE:
+		return sizeof(entry->hdr->cdat);
+	}
+	return 0;
+}
+
+static enum acpi_subtable_type __init_or_fwtbl_lib
+acpi_get_subtable_type(char *id)
+{
+	if (strncmp(id, ACPI_SIG_HMAT, 4) == 0)
+		return ACPI_SUBTABLE_HMAT;
+	if (strncmp(id, ACPI_SIG_PRMT, 4) == 0)
+		return ACPI_SUBTABLE_PRMT;
+	if (strncmp(id, ACPI_SIG_CEDT, 4) == 0)
+		return ACPI_SUBTABLE_CEDT;
+	if (strncmp(id, ACPI_SIG_CDAT, 4) == 0)
+		return CDAT_SUBTABLE;
+	return ACPI_SUBTABLE_COMMON;
+}
+
+static unsigned long __init_or_fwtbl_lib
+acpi_table_get_length(enum acpi_subtable_type type,
+		      union fw_table_header *header)
+{
+	if (type == CDAT_SUBTABLE) {
+		__le32 length = (__force __le32)header->cdat.length;
+
+		return le32_to_cpu(length);
+	}
+
+	return header->acpi.length;
+}
+
+static __init_or_fwtbl_lib int call_handler(struct acpi_subtable_proc *proc,
+					    union acpi_subtable_headers *hdr,
+					    unsigned long end)
+{
+	if (proc->handler)
+		return proc->handler(hdr, end);
+	if (proc->handler_arg)
+		return proc->handler_arg(hdr, proc->arg, end);
+	return -EINVAL;
+}
+
+/**
+ * acpi_parse_entries_array - for each proc_num find a suitable subtable
+ *
+ * @id: table id (for debugging purposes)
+ * @table_size: size of the root table
+ * @max_length: maximum size of the table (ignore if 0)
+ * @table_header: where does the table start?
+ * @proc: array of acpi_subtable_proc struct containing entry id
+ *        and associated handler with it
+ * @proc_num: how big proc is?
+ * @max_entries: how many entries can we process?
+ *
+ * For each proc_num find a subtable with proc->id and run proc->handler
+ * on it. Assumption is that there's only single handler for particular
+ * entry id.
+ *
+ * The table_size is not the size of the complete ACPI table (the length
+ * field in the header struct), but only the size of the root table; i.e.,
+ * the offset from the very first byte of the complete ACPI table, to the
+ * first byte of the very first subtable.
+ *
+ * On success returns sum of all matching entries for all proc handlers.
+ * Otherwise, -ENODEV or -EINVAL is returned.
+ */
+int __init_or_fwtbl_lib
+acpi_parse_entries_array(char *id, unsigned long table_size,
+			 union fw_table_header *table_header,
+			 unsigned long max_length,
+			 struct acpi_subtable_proc *proc,
+			 int proc_num, unsigned int max_entries)
+{
+	unsigned long table_len, table_end, subtable_len, entry_len;
+	struct acpi_subtable_entry entry;
+	enum acpi_subtable_type type;
+	int count = 0;
+	int i;
+
+	type = acpi_get_subtable_type(id);
+	table_len = acpi_table_get_length(type, table_header);
+	if (max_length && max_length < table_len)
+		table_len = max_length;
+	table_end = (unsigned long)table_header + table_len;
+
+	/* Parse all entries looking for a match. */
+
+	entry.type = type;
+	entry.hdr = (union acpi_subtable_headers *)
+	    ((unsigned long)table_header + table_size);
+	subtable_len = acpi_get_subtable_header_length(&entry);
+
+	while (((unsigned long)entry.hdr) + subtable_len < table_end) {
+		for (i = 0; i < proc_num; i++) {
+			if (acpi_get_entry_type(&entry) != proc[i].id)
+				continue;
+
+			if (!max_entries || count < max_entries)
+				if (call_handler(&proc[i], entry.hdr, table_end))
+					return -EINVAL;
+
+			proc[i].count++;
+			count++;
+			break;
+		}
+
+		/*
+		 * If entry->length is 0, break from this loop to avoid
+		 * infinite loop.
+		 */
+		entry_len = acpi_get_entry_length(&entry);
+		if (entry_len == 0) {
+			pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, proc->id);
+			return -EINVAL;
+		}
+
+		entry.hdr = (union acpi_subtable_headers *)
+		    ((unsigned long)entry.hdr + entry_len);
+	}
+
+	if (max_entries && count > max_entries) {
+		pr_warn("[%4.4s:0x%02x] ignored %i entries of %i found\n",
+			id, proc->id, count - max_entries, count);
+	}
+
+	return count;
+}
+
+int __init_or_fwtbl_lib
+cdat_table_parse(enum acpi_cdat_type type,
+		 acpi_tbl_entry_handler_arg handler_arg,
+		 void *arg,
+		 struct acpi_table_cdat *table_header,
+		 unsigned long length)
+{
+	struct acpi_subtable_proc proc = {
+		.id		= type,
+		.handler_arg	= handler_arg,
+		.arg		= arg,
+	};
+
+	if (!table_header)
+		return -EINVAL;
+
+	return acpi_parse_entries_array(ACPI_SIG_CDAT,
+					sizeof(struct acpi_table_cdat),
+					(union fw_table_header *)table_header,
+					length, &proc, 1, 0);
+}
+EXPORT_SYMBOL_FWTBL_LIB(cdat_table_parse);