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, 214 insertions, 0 deletions

diff --git a/scripts/dtc/fdtoverlay.c b/scripts/dtc/fdtoverlay.c
new file mode 100644
index 000000000..ee1eb8f3a
--- /dev/null
+++ b/scripts/dtc/fdtoverlay.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2017 Konsulko Group Inc. All rights reserved.
+ *
+ * Author:
+ *	 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ */
+
+#include <assert.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include <libfdt.h>
+
+#include "util.h"
+
+#define BUF_INCREMENT	65536
+
+/* Usage related data. */
+static const char usage_synopsis[] =
+	"apply a number of overlays to a base blob\n"
+	"	fdtoverlay <options> [<overlay.dtbo> [<overlay.dtbo>]]";
+static const char usage_short_opts[] = "i:o:v" USAGE_COMMON_SHORT_OPTS;
+static struct option const usage_long_opts[] = {
+	{"input",            required_argument, NULL, 'i'},
+	{"output",	     required_argument, NULL, 'o'},
+	{"verbose",	           no_argument, NULL, 'v'},
+	USAGE_COMMON_LONG_OPTS,
+};
+static const char * const usage_opts_help[] = {
+	"Input base DT blob",
+	"Output DT blob",
+	"Verbose messages",
+	USAGE_COMMON_OPTS_HELP
+};
+
+int verbose = 0;
+
+static void *apply_one(char *base, const char *overlay, size_t *buf_len,
+		       const char *name)
+{
+	char *tmp = NULL;
+	char *tmpo;
+	int ret;
+	bool has_symbols;
+
+	/*
+	 * We take copies first, because a failed apply can trash
+	 * both the base blob and the overlay
+	 */
+	tmpo = xmalloc(fdt_totalsize(overlay));
+
+	do {
+		tmp = xrealloc(tmp, *buf_len);
+		ret = fdt_open_into(base, tmp, *buf_len);
+		if (ret) {
+			fprintf(stderr,
+				"\nFailed to make temporary copy: %s\n",
+				fdt_strerror(ret));
+			goto fail;
+		}
+		ret = fdt_path_offset(tmp, "/__symbols__");
+		has_symbols = ret >= 0;
+
+		memcpy(tmpo, overlay, fdt_totalsize(overlay));
+
+		ret = fdt_overlay_apply(tmp, tmpo);
+		if (ret == -FDT_ERR_NOSPACE) {
+			*buf_len += BUF_INCREMENT;
+		}
+	} while (ret == -FDT_ERR_NOSPACE);
+
+	if (ret) {
+		fprintf(stderr, "\nFailed to apply '%s': %s\n",
+			name, fdt_strerror(ret));
+		if (!has_symbols) {
+			fprintf(stderr,
+				"base blob does not have a '/__symbols__' node, "
+				"make sure you have compiled the base blob with '-@' option\n");
+		}
+		goto fail;
+	}
+
+	free(base);
+	free(tmpo);
+	return tmp;
+
+fail:
+	free(tmpo);
+	if (tmp)
+		free(tmp);
+
+	return NULL;
+}
+static int do_fdtoverlay(const char *input_filename,
+			 const char *output_filename,
+			 int argc, char *argv[])
+{
+	char *blob = NULL;
+	char **ovblob = NULL;
+	size_t buf_len;
+	int i, ret = -1;
+
+	blob = utilfdt_read(input_filename, &buf_len);
+	if (!blob) {
+		fprintf(stderr, "\nFailed to read '%s'\n", input_filename);
+		goto out_err;
+	}
+	if (fdt_totalsize(blob) > buf_len) {
+		fprintf(stderr,
+ "\nBase blob is incomplete (%lu / %" PRIu32 " bytes read)\n",
+			(unsigned long)buf_len, fdt_totalsize(blob));
+		goto out_err;
+	}
+
+	/* allocate blob pointer array */
+	ovblob = xmalloc(sizeof(*ovblob) * argc);
+	memset(ovblob, 0, sizeof(*ovblob) * argc);
+
+	/* read and keep track of the overlay blobs */
+	for (i = 0; i < argc; i++) {
+		size_t ov_len;
+		ovblob[i] = utilfdt_read(argv[i], &ov_len);
+		if (!ovblob[i]) {
+			fprintf(stderr, "\nFailed to read '%s'\n", argv[i]);
+			goto out_err;
+		}
+		if (fdt_totalsize(ovblob[i]) > ov_len) {
+			fprintf(stderr,
+"\nOverlay '%s' is incomplete (%lu / %" PRIu32 " bytes read)\n",
+				argv[i], (unsigned long)ov_len,
+				fdt_totalsize(ovblob[i]));
+			goto out_err;
+		}
+	}
+
+	buf_len = fdt_totalsize(blob);
+
+	/* apply the overlays in sequence */
+	for (i = 0; i < argc; i++) {
+		blob = apply_one(blob, ovblob[i], &buf_len, argv[i]);
+		if (!blob)
+			goto out_err;
+	}
+
+	fdt_pack(blob);
+	ret = utilfdt_write(output_filename, blob);
+	if (ret)
+		fprintf(stderr, "\nFailed to write '%s'\n",
+			output_filename);
+
+out_err:
+	if (ovblob) {
+		for (i = 0; i < argc; i++) {
+			if (ovblob[i])
+				free(ovblob[i]);
+		}
+		free(ovblob);
+	}
+	free(blob);
+
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	int opt, i;
+	char *input_filename = NULL;
+	char *output_filename = NULL;
+
+	while ((opt = util_getopt_long()) != EOF) {
+		switch (opt) {
+		case_USAGE_COMMON_FLAGS
+
+		case 'i':
+			input_filename = optarg;
+			break;
+		case 'o':
+			output_filename = optarg;
+			break;
+		case 'v':
+			verbose = 1;
+			break;
+		}
+	}
+
+	if (!input_filename)
+		usage("missing input file");
+
+	if (!output_filename)
+		usage("missing output file");
+
+	argv += optind;
+	argc -= optind;
+
+	if (argc <= 0)
+		usage("missing overlay file(s)");
+
+	if (verbose) {
+		printf("input  = %s\n", input_filename);
+		printf("output = %s\n", output_filename);
+		for (i = 0; i < argc; i++)
+			printf("overlay[%d] = %s\n", i, argv[i]);
+	}
+
+	if (do_fdtoverlay(input_filename, output_filename, argc, argv))
+		return 1;
+
+	return 0;
+}