Latest update.

providers/implementations/ciphers/cipher_chacha20_hw.c

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+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+/* chacha20 cipher implementation */
+
+#include "cipher_chacha20.h"
+
+static int chacha20_initkey(PROV_CIPHER_CTX *bctx, const uint8_t *key,
+                            size_t keylen)
+{
+    PROV_CHACHA20_CTX *ctx = (PROV_CHACHA20_CTX *)bctx;
+    unsigned int i;
+
+    if (key != NULL) {
+        for (i = 0; i < CHACHA_KEY_SIZE; i += 4)
+            ctx->key.d[i / 4] = CHACHA_U8TOU32(key + i);
+    }
+    ctx->partial_len = 0;
+    return 1;
+}
+
+static int chacha20_initiv(PROV_CIPHER_CTX *bctx)
+{
+    PROV_CHACHA20_CTX *ctx = (PROV_CHACHA20_CTX *)bctx;
+    unsigned int i;
+
+    if (bctx->iv_set) {
+        for (i = 0; i < CHACHA_CTR_SIZE; i += 4)
+            ctx->counter[i / 4] = CHACHA_U8TOU32(bctx->oiv + i);
+    }
+    return 1;
+}
+
+static int chacha20_cipher(PROV_CIPHER_CTX *bctx, unsigned char *out,
+                           const unsigned char *in, size_t inl)
+{
+    PROV_CHACHA20_CTX *ctx = (PROV_CHACHA20_CTX *)bctx;
+    unsigned int n, rem, ctr32;
+
+    n = ctx->partial_len;
+    if (n > 0) {
+        while (inl > 0 && n < CHACHA_BLK_SIZE) {
+            *out++ = *in++ ^ ctx->buf[n++];
+            inl--;
+        }
+        ctx->partial_len = n;
+
+        if (inl == 0)
+            return 1;
+
+        if (n == CHACHA_BLK_SIZE) {
+            ctx->partial_len = 0;
+            ctx->counter[0]++;
+            if (ctx->counter[0] == 0)
+                ctx->counter[1]++;
+        }
+    }
+
+    rem = (unsigned int)(inl % CHACHA_BLK_SIZE);
+    inl -= rem;
+    ctr32 = ctx->counter[0];
+    while (inl >= CHACHA_BLK_SIZE) {
+        size_t blocks = inl / CHACHA_BLK_SIZE;
+
+        /*
+         * 1<<28 is just a not-so-small yet not-so-large number...
+         * Below condition is practically never met, but it has to
+         * be checked for code correctness.
+         */
+        if (sizeof(size_t) > sizeof(unsigned int) && blocks > (1U << 28))
+            blocks = (1U << 28);
+
+        /*
+         * As ChaCha20_ctr32 operates on 32-bit counter, caller
+         * has to handle overflow. 'if' below detects the
+         * overflow, which is then handled by limiting the
+         * amount of blocks to the exact overflow point...
+         */
+        ctr32 += (unsigned int)blocks;
+        if (ctr32 < blocks) {
+            blocks -= ctr32;
+            ctr32 = 0;
+        }
+        blocks *= CHACHA_BLK_SIZE;
+        ChaCha20_ctr32(out, in, blocks, ctx->key.d, ctx->counter);
+        inl -= blocks;
+        in += blocks;
+        out += blocks;
+
+        ctx->counter[0] = ctr32;
+        if (ctr32 == 0) ctx->counter[1]++;
+    }
+
+    if (rem > 0) {
+        memset(ctx->buf, 0, sizeof(ctx->buf));
+        ChaCha20_ctr32(ctx->buf, ctx->buf, CHACHA_BLK_SIZE,
+                       ctx->key.d, ctx->counter);
+        for (n = 0; n < rem; n++)
+            out[n] = in[n] ^ ctx->buf[n];
+        ctx->partial_len = rem;
+    }
+
+    return 1;
+}
+
+static const PROV_CIPHER_HW_CHACHA20 chacha20_hw = {
+    { chacha20_initkey, chacha20_cipher },
+    chacha20_initiv
+};
+
+const PROV_CIPHER_HW *PROV_CIPHER_HW_chacha20(size_t keybits)
+{
+    return (PROV_CIPHER_HW *)&chacha20_hw;
+}
+