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, 82 insertions, 0 deletions

diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c
new file mode 100644
index 000000000..f80a67c09
--- /dev/null
+++ b/arch/mips/lib/uncached.c
@@ -0,0 +1,82 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2005 Thiemo Seufer
+ * Copyright (C) 2005  MIPS Technologies, Inc.	All rights reserved.
+ *	Author: Maciej W. Rozycki <macro@mips.com>
+ */
+
+
+#include <asm/addrspace.h>
+#include <asm/bug.h>
+#include <asm/cacheflush.h>
+
+#ifndef CKSEG2
+#define CKSEG2 CKSSEG
+#endif
+#ifndef TO_PHYS_MASK
+#define TO_PHYS_MASK -1
+#endif
+
+/*
+ * FUNC is executed in one of the uncached segments, depending on its
+ * original address as follows:
+ *
+ * 1. If the original address is in CKSEG0 or CKSEG1, then the uncached
+ *    segment used is CKSEG1.
+ * 2. If the original address is in XKPHYS, then the uncached segment
+ *    used is XKPHYS(2).
+ * 3. Otherwise it's a bug.
+ *
+ * The same remapping is done with the stack pointer.  Stack handling
+ * works because we don't handle stack arguments or more complex return
+ * values, so we can avoid sharing the same stack area between a cached
+ * and the uncached mode.
+ */
+unsigned long run_uncached(void *func)
+{
+	register long ret __asm__("$2");
+	long lfunc = (long)func, ufunc;
+	long usp;
+	long sp;
+
+	__asm__("move %0, $sp" : "=r" (sp));
+
+	if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
+		usp = CKSEG1ADDR(sp);
+#ifdef CONFIG_64BIT
+	else if ((long long)sp >= (long long)PHYS_TO_XKPHYS(0, 0) &&
+		 (long long)sp < (long long)PHYS_TO_XKPHYS(8, 0))
+		usp = PHYS_TO_XKPHYS(K_CALG_UNCACHED,
+				     XKPHYS_TO_PHYS((long long)sp));
+#endif
+	else {
+		BUG();
+		usp = sp;
+	}
+	if (lfunc >= (long)CKSEG0 && lfunc < (long)CKSEG2)
+		ufunc = CKSEG1ADDR(lfunc);
+#ifdef CONFIG_64BIT
+	else if ((long long)lfunc >= (long long)PHYS_TO_XKPHYS(0, 0) &&
+		 (long long)lfunc < (long long)PHYS_TO_XKPHYS(8, 0))
+		ufunc = PHYS_TO_XKPHYS(K_CALG_UNCACHED,
+				       XKPHYS_TO_PHYS((long long)lfunc));
+#endif
+	else {
+		BUG();
+		ufunc = lfunc;
+	}
+
+	__asm__ __volatile__ (
+		"	move	$16, $sp\n"
+		"	move	$sp, %1\n"
+		"	jalr	%2\n"
+		"	move	$sp, $16"
+		: "=r" (ret)
+		: "r" (usp), "r" (ufunc)
+		: "$16", "$31");
+
+	return ret;
+}