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, 92 insertions, 0 deletions

diff --git a/crypto/sm4_generic.c b/crypto/sm4_generic.c
new file mode 100644
index 000000000..d57444e84
--- /dev/null
+++ b/crypto/sm4_generic.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * SM4 Cipher Algorithm.
+ *
+ * Copyright (C) 2018 ARM Limited or its affiliates.
+ * All rights reserved.
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/sm4.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <asm/byteorder.h>
+#include <linux/unaligned.h>
+
+/**
+ * sm4_setkey - Set the SM4 key.
+ * @tfm:	The %crypto_tfm that is used in the context.
+ * @in_key:	The input key.
+ * @key_len:	The size of the key.
+ *
+ * This function uses sm4_expandkey() to expand the key.
+ * &sm4_ctx _must_ be the private data embedded in @tfm which is
+ * retrieved with crypto_tfm_ctx().
+ *
+ * Return: 0 on success; -EINVAL on failure (only happens for bad key lengths)
+ */
+static int sm4_setkey(struct crypto_tfm *tfm, const u8 *in_key,
+		       unsigned int key_len)
+{
+	struct sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	return sm4_expandkey(ctx, in_key, key_len);
+}
+
+/* encrypt a block of text */
+
+static void sm4_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	sm4_crypt_block(ctx->rkey_enc, out, in);
+}
+
+/* decrypt a block of text */
+
+static void sm4_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	sm4_crypt_block(ctx->rkey_dec, out, in);
+}
+
+static struct crypto_alg sm4_alg = {
+	.cra_name		=	"sm4",
+	.cra_driver_name	=	"sm4-generic",
+	.cra_priority		=	100,
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	SM4_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct sm4_ctx),
+	.cra_module		=	THIS_MODULE,
+	.cra_u			=	{
+		.cipher = {
+			.cia_min_keysize	=	SM4_KEY_SIZE,
+			.cia_max_keysize	=	SM4_KEY_SIZE,
+			.cia_setkey		=	sm4_setkey,
+			.cia_encrypt		=	sm4_encrypt,
+			.cia_decrypt		=	sm4_decrypt
+		}
+	}
+};
+
+static int __init sm4_init(void)
+{
+	return crypto_register_alg(&sm4_alg);
+}
+
+static void __exit sm4_fini(void)
+{
+	crypto_unregister_alg(&sm4_alg);
+}
+
+module_init(sm4_init);
+module_exit(sm4_fini);
+
+MODULE_DESCRIPTION("SM4 Cipher Algorithm");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("sm4");
+MODULE_ALIAS_CRYPTO("sm4-generic");