FreeBSD/Linux Kernel Cross Reference
sys/crypto/openssl/ossl_poly1305.c

     /*
      * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
      *
      * Licensed under the OpenSSL license (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
      */
     
    #include <sys/libkern.h>
    #include <sys/malloc.h>
    
    #include <opencrypto/cryptodev.h>
    #include <opencrypto/xform_auth.h>
    
    #include <crypto/openssl/ossl.h>
    #include <crypto/openssl/ossl_poly1305.h>
    
    #define POLY1305_ASM
    
    /* From crypto/poly1305/poly1305.c */
    
    /* pick 32-bit unsigned integer in little endian order */
    static unsigned int U8TOU32(const unsigned char *p)
    {
        return (((unsigned int)(p[0] & 0xff)) |
                ((unsigned int)(p[1] & 0xff) << 8) |
                ((unsigned int)(p[2] & 0xff) << 16) |
                ((unsigned int)(p[3] & 0xff) << 24));
    }
    
    /*
     * Implementations can be classified by amount of significant bits in
     * words making up the multi-precision value, or in other words radix
     * or base of numerical representation, e.g. base 2^64, base 2^32,
     * base 2^26. Complementary characteristic is how wide is the result of
     * multiplication of pair of digits, e.g. it would take 128 bits to
     * accommodate multiplication result in base 2^64 case. These are used
     * interchangeably. To describe implementation that is. But interface
     * is designed to isolate this so that low-level primitives implemented
     * in assembly can be self-contained/self-coherent.
     */
    int poly1305_init(void *ctx, const unsigned char key[16], void *func);
    void poly1305_blocks(void *ctx, const unsigned char *inp, size_t len,
                         unsigned int padbit);
    void poly1305_emit(void *ctx, unsigned char mac[16],
                       const unsigned int nonce[4]);
    
    void Poly1305_Init(POLY1305 *ctx, const unsigned char key[32])
    {
        ctx->nonce[0] = U8TOU32(&key[16]);
        ctx->nonce[1] = U8TOU32(&key[20]);
        ctx->nonce[2] = U8TOU32(&key[24]);
        ctx->nonce[3] = U8TOU32(&key[28]);
    
        /*
         * Unlike reference poly1305_init assembly counterpart is expected
         * to return a value: non-zero if it initializes ctx->func, and zero
         * otherwise. Latter is to simplify assembly in cases when there no
         * multiple code paths to switch between.
         */
        if (!poly1305_init(ctx->opaque, key, &ctx->func)) {
            ctx->func.blocks = poly1305_blocks;
            ctx->func.emit = poly1305_emit;
        }
    
        ctx->num = 0;
    
    }
    
    #ifdef POLY1305_ASM
    /*
     * This "eclipses" poly1305_blocks and poly1305_emit, but it's
     * conscious choice imposed by -Wshadow compiler warnings.
     */
    # define poly1305_blocks (*poly1305_blocks_p)
    # define poly1305_emit   (*poly1305_emit_p)
    #endif
    
    void Poly1305_Update(POLY1305 *ctx, const unsigned char *inp, size_t len)
    {
    #ifdef POLY1305_ASM
        /*
         * As documented, poly1305_blocks is never called with input
         * longer than single block and padbit argument set to 0. This
         * property is fluently used in assembly modules to optimize
         * padbit handling on loop boundary.
         */
        poly1305_blocks_f poly1305_blocks_p = ctx->func.blocks;
    #endif
        size_t rem, num;
    
        if ((num = ctx->num)) {
            rem = POLY1305_BLOCK_SIZE - num;
            if (len >= rem) {
                memcpy(ctx->data + num, inp, rem);
                poly1305_blocks(ctx->opaque, ctx->data, POLY1305_BLOCK_SIZE, 1);
                inp += rem;
                len -= rem;
           } else {
               /* Still not enough data to process a block. */
               memcpy(ctx->data + num, inp, len);
               ctx->num = num + len;
               return;
           }
       }
   
       rem = len % POLY1305_BLOCK_SIZE;
       len -= rem;
   
       if (len >= POLY1305_BLOCK_SIZE) {
           poly1305_blocks(ctx->opaque, inp, len, 1);
           inp += len;
       }
   
       if (rem)
           memcpy(ctx->data, inp, rem);
   
       ctx->num = rem;
   }
   
   void Poly1305_Final(POLY1305 *ctx, unsigned char mac[16])
   {
   #ifdef POLY1305_ASM
       poly1305_blocks_f poly1305_blocks_p = ctx->func.blocks;
       poly1305_emit_f poly1305_emit_p = ctx->func.emit;
   #endif
       size_t num;
   
       if ((num = ctx->num)) {
           ctx->data[num++] = 1;   /* pad bit */
           while (num < POLY1305_BLOCK_SIZE)
               ctx->data[num++] = 0;
           poly1305_blocks(ctx->opaque, ctx->data, POLY1305_BLOCK_SIZE, 0);
       }
   
       poly1305_emit(ctx->opaque, mac, ctx->nonce);
   
       /* zero out the state */
       OPENSSL_cleanse(ctx, sizeof(*ctx));
   }
   
   static void
   ossl_poly1305_init(void *vctx)
   {
   }
   
   static void
   ossl_poly1305_setkey(void *vctx, const uint8_t *key, u_int klen)
   {
           MPASS(klen == 32);
           Poly1305_Init(vctx, key);
   }
   
   int
   ossl_poly1305_update(void *vctx, const void *buf, u_int len)
   {
           Poly1305_Update(vctx, buf, len);
           return (0);
   }
   
   static void
   ossl_poly1305_final(uint8_t *digest, void *vctx)
   {
           Poly1305_Final(vctx, digest);
   }
   
   struct auth_hash ossl_hash_poly1305 = {
           .type = CRYPTO_POLY1305,
           .name = "OpenSSL-Poly1305",
           .hashsize = POLY1305_HASH_LEN,
           .ctxsize = sizeof(struct poly1305_context),
           .blocksize = POLY1305_BLOCK_SIZE,
           .Init = ossl_poly1305_init,
           .Setkey = ossl_poly1305_setkey,
           .Update = ossl_poly1305_update,
           .Final = ossl_poly1305_final,
   };
   
   _Static_assert(sizeof(struct poly1305_context) <=
       sizeof(struct ossl_hash_context), "ossl_hash_context too small");

Cache object: af97f426b391641cbb0b6392ce324c7d