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, 86 insertions, 0 deletions

diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c
new file mode 100644
index 000000000..feb6dbd7c
--- /dev/null
+++ b/arch/x86/boot/cpu.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007-2008 rPath, Inc. - All Rights Reserved
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/x86/boot/cpu.c
+ *
+ * Check for obligatory CPU features and abort if the features are not
+ * present.
+ */
+
+#include "boot.h"
+#include "cpustr.h"
+
+static char *cpu_name(int level)
+{
+	static char buf[6];
+
+	if (level == 64) {
+		return "x86-64";
+	} else {
+		if (level == 15)
+			level = 6;
+		sprintf(buf, "i%d86", level);
+		return buf;
+	}
+}
+
+static void show_cap_strs(u32 *err_flags)
+{
+	int i, j;
+	const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs;
+	for (i = 0; i < NCAPINTS; i++) {
+		u32 e = err_flags[i];
+		for (j = 0; j < 32; j++) {
+			if (msg_strs[0] < i ||
+			    (msg_strs[0] == i && msg_strs[1] < j)) {
+				/* Skip to the next string */
+				msg_strs += 2;
+				while (*msg_strs++)
+					;
+			}
+			if (e & 1) {
+				if (msg_strs[0] == i &&
+				    msg_strs[1] == j &&
+				    msg_strs[2])
+					printf("%s ", msg_strs+2);
+				else
+					printf("%d:%d ", i, j);
+			}
+			e >>= 1;
+		}
+	}
+}
+
+int validate_cpu(void)
+{
+	u32 *err_flags;
+	int cpu_level, req_level;
+
+	check_cpu(&cpu_level, &req_level, &err_flags);
+
+	if (cpu_level < req_level) {
+		printf("This kernel requires an %s CPU, ",
+		       cpu_name(req_level));
+		printf("but only detected an %s CPU.\n",
+		       cpu_name(cpu_level));
+		return -1;
+	}
+
+	if (err_flags) {
+		puts("This kernel requires the following features "
+		     "not present on the CPU:\n");
+		show_cap_strs(err_flags);
+		putchar('\n');
+		return -1;
+	} else if (check_knl_erratum()) {
+		return -1;
+	} else {
+		return 0;
+	}
+}