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-rw-r--r--net/mac80211/michael.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/net/mac80211/michael.c b/net/mac80211/michael.c
new file mode 100644
index 0000000000..a57502d9ff
--- /dev/null
+++ b/net/mac80211/michael.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Michael MIC implementation - optimized for TKIP MIC operations
+ * Copyright 2002-2003, Instant802 Networks, Inc.
+ */
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <linux/ieee80211.h>
+#include <asm/unaligned.h>
+
+#include "michael.h"
+
+static void michael_block(struct michael_mic_ctx *mctx, u32 val)
+{
+ mctx->l ^= val;
+ mctx->r ^= rol32(mctx->l, 17);
+ mctx->l += mctx->r;
+ mctx->r ^= ((mctx->l & 0xff00ff00) >> 8) |
+ ((mctx->l & 0x00ff00ff) << 8);
+ mctx->l += mctx->r;
+ mctx->r ^= rol32(mctx->l, 3);
+ mctx->l += mctx->r;
+ mctx->r ^= ror32(mctx->l, 2);
+ mctx->l += mctx->r;
+}
+
+static void michael_mic_hdr(struct michael_mic_ctx *mctx, const u8 *key,
+ struct ieee80211_hdr *hdr)
+{
+ u8 *da, *sa, tid;
+
+ da = ieee80211_get_DA(hdr);
+ sa = ieee80211_get_SA(hdr);
+ if (ieee80211_is_data_qos(hdr->frame_control))
+ tid = ieee80211_get_tid(hdr);
+ else
+ tid = 0;
+
+ mctx->l = get_unaligned_le32(key);
+ mctx->r = get_unaligned_le32(key + 4);
+
+ /*
+ * A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC
+ * calculation, but it is _not_ transmitted
+ */
+ michael_block(mctx, get_unaligned_le32(da));
+ michael_block(mctx, get_unaligned_le16(&da[4]) |
+ (get_unaligned_le16(sa) << 16));
+ michael_block(mctx, get_unaligned_le32(&sa[2]));
+ michael_block(mctx, tid);
+}
+
+void michael_mic(const u8 *key, struct ieee80211_hdr *hdr,
+ const u8 *data, size_t data_len, u8 *mic)
+{
+ u32 val;
+ size_t block, blocks, left;
+ struct michael_mic_ctx mctx;
+
+ michael_mic_hdr(&mctx, key, hdr);
+
+ /* Real data */
+ blocks = data_len / 4;
+ left = data_len % 4;
+
+ for (block = 0; block < blocks; block++)
+ michael_block(&mctx, get_unaligned_le32(&data[block * 4]));
+
+ /* Partial block of 0..3 bytes and padding: 0x5a + 4..7 zeros to make
+ * total length a multiple of 4. */
+ val = 0x5a;
+ while (left > 0) {
+ val <<= 8;
+ left--;
+ val |= data[blocks * 4 + left];
+ }
+
+ michael_block(&mctx, val);
+ michael_block(&mctx, 0);
+
+ put_unaligned_le32(mctx.l, mic);
+ put_unaligned_le32(mctx.r, mic + 4);
+}