summaryrefslogtreecommitdiffstats
path: root/crypto/michael_mic.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--crypto/michael_mic.c176
1 files changed, 176 insertions, 0 deletions
diff --git a/crypto/michael_mic.c b/crypto/michael_mic.c
new file mode 100644
index 000000000..f4c310496
--- /dev/null
+++ b/crypto/michael_mic.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Cryptographic API
+ *
+ * Michael MIC (IEEE 802.11i/TKIP) keyed digest
+ *
+ * Copyright (c) 2004 Jouni Malinen <j@w1.fi>
+ */
+#include <crypto/internal/hash.h>
+#include <asm/unaligned.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+
+struct michael_mic_ctx {
+ u32 l, r;
+};
+
+struct michael_mic_desc_ctx {
+ __le32 pending;
+ size_t pending_len;
+
+ u32 l, r;
+};
+
+static inline u32 xswap(u32 val)
+{
+ return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
+}
+
+
+#define michael_block(l, r) \
+do { \
+ r ^= rol32(l, 17); \
+ l += r; \
+ r ^= xswap(l); \
+ l += r; \
+ r ^= rol32(l, 3); \
+ l += r; \
+ r ^= ror32(l, 2); \
+ l += r; \
+} while (0)
+
+
+static int michael_init(struct shash_desc *desc)
+{
+ struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
+ struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ mctx->pending_len = 0;
+ mctx->l = ctx->l;
+ mctx->r = ctx->r;
+
+ return 0;
+}
+
+
+static int michael_update(struct shash_desc *desc, const u8 *data,
+ unsigned int len)
+{
+ struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
+
+ if (mctx->pending_len) {
+ int flen = 4 - mctx->pending_len;
+ if (flen > len)
+ flen = len;
+ memcpy((u8 *)&mctx->pending + mctx->pending_len, data, flen);
+ mctx->pending_len += flen;
+ data += flen;
+ len -= flen;
+
+ if (mctx->pending_len < 4)
+ return 0;
+
+ mctx->l ^= le32_to_cpu(mctx->pending);
+ michael_block(mctx->l, mctx->r);
+ mctx->pending_len = 0;
+ }
+
+ while (len >= 4) {
+ mctx->l ^= get_unaligned_le32(data);
+ michael_block(mctx->l, mctx->r);
+ data += 4;
+ len -= 4;
+ }
+
+ if (len > 0) {
+ mctx->pending_len = len;
+ memcpy(&mctx->pending, data, len);
+ }
+
+ return 0;
+}
+
+
+static int michael_final(struct shash_desc *desc, u8 *out)
+{
+ struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
+ u8 *data = (u8 *)&mctx->pending;
+
+ /* Last block and padding (0x5a, 4..7 x 0) */
+ switch (mctx->pending_len) {
+ case 0:
+ mctx->l ^= 0x5a;
+ break;
+ case 1:
+ mctx->l ^= data[0] | 0x5a00;
+ break;
+ case 2:
+ mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
+ break;
+ case 3:
+ mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
+ 0x5a000000;
+ break;
+ }
+ michael_block(mctx->l, mctx->r);
+ /* l ^= 0; */
+ michael_block(mctx->l, mctx->r);
+
+ put_unaligned_le32(mctx->l, out);
+ put_unaligned_le32(mctx->r, out + 4);
+
+ return 0;
+}
+
+
+static int michael_setkey(struct crypto_shash *tfm, const u8 *key,
+ unsigned int keylen)
+{
+ struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);
+
+ if (keylen != 8)
+ return -EINVAL;
+
+ mctx->l = get_unaligned_le32(key);
+ mctx->r = get_unaligned_le32(key + 4);
+ return 0;
+}
+
+static struct shash_alg alg = {
+ .digestsize = 8,
+ .setkey = michael_setkey,
+ .init = michael_init,
+ .update = michael_update,
+ .final = michael_final,
+ .descsize = sizeof(struct michael_mic_desc_ctx),
+ .base = {
+ .cra_name = "michael_mic",
+ .cra_driver_name = "michael_mic-generic",
+ .cra_blocksize = 8,
+ .cra_ctxsize = sizeof(struct michael_mic_ctx),
+ .cra_module = THIS_MODULE,
+ }
+};
+
+static int __init michael_mic_init(void)
+{
+ return crypto_register_shash(&alg);
+}
+
+
+static void __exit michael_mic_exit(void)
+{
+ crypto_unregister_shash(&alg);
+}
+
+
+subsys_initcall(michael_mic_init);
+module_exit(michael_mic_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Michael MIC");
+MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");
+MODULE_ALIAS_CRYPTO("michael_mic");