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, 53 insertions, 0 deletions

diff --git a/tools/perf/tests/genelf.c b/tools/perf/tests/genelf.c
new file mode 100644
index 000000000..95f3be1b6
--- /dev/null
+++ b/tools/perf/tests/genelf.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/compiler.h>
+
+#include "debug.h"
+#include "tests.h"
+
+#ifdef HAVE_JITDUMP
+#include <libelf.h>
+#include "../util/genelf.h"
+#endif
+
+#define TEMPL "/tmp/perf-test-XXXXXX"
+
+static int test__jit_write_elf(struct test_suite *test __maybe_unused,
+			       int subtest __maybe_unused)
+{
+#ifdef HAVE_JITDUMP
+	static unsigned char x86_code[] = {
+		0xBB, 0x2A, 0x00, 0x00, 0x00, /* movl $42, %ebx */
+		0xB8, 0x01, 0x00, 0x00, 0x00, /* movl $1, %eax */
+		0xCD, 0x80            /* int $0x80 */
+	};
+	char path[PATH_MAX];
+	int fd, ret;
+
+	strcpy(path, TEMPL);
+
+	fd = mkstemp(path);
+	if (fd < 0) {
+		perror("mkstemp failed");
+		return TEST_FAIL;
+	}
+
+	pr_info("Writing jit code to: %s\n", path);
+
+	ret = jit_write_elf(fd, 0, "main", x86_code, sizeof(x86_code),
+			NULL, 0, NULL, 0, 0);
+	close(fd);
+
+	unlink(path);
+
+	return ret ? TEST_FAIL : 0;
+#else
+	return TEST_SKIP;
+#endif
+}
+
+DEFINE_SUITE("Test jit_write_elf", jit_write_elf);