Commit 14bb100b authored by Andy Polyakov's avatar Andy Polyakov
Browse files

modes/ocb128.c: address undefined behaviour warning. 



Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3526)
parent f83409a6

crypto/modes/ocb128.c

+58 −58
Original line number Diff line number Diff line
@@ -274,8 +274,7 @@ int CRYPTO_ocb128_aad(OCB128_CONTEXT *ctx, const unsigned char *aad, 
{

    u64 i, all_num_blocks;

    size_t num_blocks, last_len;

    OCB_BLOCK tmp1;

    OCB_BLOCK tmp2;

    OCB_BLOCK tmp;



    /* Calculate the number of blocks of AAD provided now, and so far */

    num_blocks = len / 16;
@@ -284,7 +283,6 @@ int CRYPTO_ocb128_aad(OCB128_CONTEXT *ctx, const unsigned char *aad, 
    /* Loop through all full blocks of AAD */

    for (i = ctx->blocks_hashed + 1; i <= all_num_blocks; i++) {

        OCB_BLOCK *lookup;

        OCB_BLOCK *aad_block;



        /* Offset_i = Offset_{i-1} xor L_{ntz(i)} */

        lookup = ocb_lookup_l(ctx, ocb_ntz(i));
@@ -292,11 +290,13 @@ int CRYPTO_ocb128_aad(OCB128_CONTEXT *ctx, const unsigned char *aad, 
            return 0;

        ocb_block16_xor(&ctx->offset_aad, lookup, &ctx->offset_aad);



        memcpy(tmp.c, aad, 16);

        aad += 16;



        /* Sum_i = Sum_{i-1} xor ENCIPHER(K, A_i xor Offset_i) */

        aad_block = (OCB_BLOCK *)(aad + ((i - ctx->blocks_hashed - 1) * 16));

        ocb_block16_xor_misaligned(&ctx->offset_aad, aad_block, &tmp1);

        ctx->encrypt(tmp1.c, tmp2.c, ctx->keyenc);

        ocb_block16_xor(&ctx->sum, &tmp2, &ctx->sum);

        ocb_block16_xor(&ctx->offset_aad, &tmp, &tmp);

        ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);

        ocb_block16_xor(&tmp, &ctx->sum, &ctx->sum);

    }



    /*
@@ -310,14 +310,14 @@ int CRYPTO_ocb128_aad(OCB128_CONTEXT *ctx, const unsigned char *aad, 
        ocb_block16_xor(&ctx->offset_aad, &ctx->l_star, &ctx->offset_aad);



        /* CipherInput = (A_* || 1 || zeros(127-bitlen(A_*))) xor Offset_* */

        memset(&tmp1, 0, 16);

        memcpy(&tmp1, aad + (num_blocks * 16), last_len);

        ((unsigned char *)&tmp1)[last_len] = 0x80;

        ocb_block16_xor(&ctx->offset_aad, &tmp1, &tmp2);

        memset(tmp.c, 0, 16);

        memcpy(tmp.c, aad, last_len);

        tmp.c[last_len] = 0x80;

        ocb_block16_xor(&ctx->offset_aad, &tmp, &tmp);



        /* Sum = Sum_m xor ENCIPHER(K, CipherInput) */

        ctx->encrypt(tmp2.c, tmp1.c, ctx->keyenc);

        ocb_block16_xor(&ctx->sum, &tmp1, &ctx->sum);

        ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);

        ocb_block16_xor(&tmp, &ctx->sum, &ctx->sum);

    }



    ctx->blocks_hashed = all_num_blocks;
@@ -335,9 +335,6 @@ int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx, 
{

    u64 i, all_num_blocks;

    size_t num_blocks, last_len;

    OCB_BLOCK tmp1;

    OCB_BLOCK tmp2;

    OCB_BLOCK pad;



    /*

     * Calculate the number of blocks of data to be encrypted provided now, and
@@ -366,8 +363,7 @@ int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx, 
        /* Loop through all full blocks to be encrypted */

        for (i = ctx->blocks_processed + 1; i <= all_num_blocks; i++) {

            OCB_BLOCK *lookup;

            OCB_BLOCK *inblock;

            OCB_BLOCK *outblock;

            OCB_BLOCK tmp;



            /* Offset_i = Offset_{i-1} xor L_{ntz(i)} */

            lookup = ocb_lookup_l(ctx, ocb_ntz(i));
@@ -375,16 +371,19 @@ int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx, 
                return 0;

            ocb_block16_xor(&ctx->offset, lookup, &ctx->offset);



            /* C_i = Offset_i xor ENCIPHER(K, P_i xor Offset_i) */

            inblock =

                (OCB_BLOCK *)(in + ((i - ctx->blocks_processed - 1) * 16));

            ocb_block16_xor_misaligned(&ctx->offset, inblock, &tmp1);

            memcpy(tmp.c, in, 16);

            in += 16;



            /* Checksum_i = Checksum_{i-1} xor P_i */

            ocb_block16_xor_misaligned(&ctx->checksum, inblock, &ctx->checksum);

            ctx->encrypt(tmp1.c, tmp2.c, ctx->keyenc);

            outblock =

                (OCB_BLOCK *)(out + ((i - ctx->blocks_processed - 1) * 16));

            ocb_block16_xor_misaligned(&ctx->offset, &tmp2, outblock);

            ocb_block16_xor(&tmp, &ctx->checksum, &ctx->checksum);



            /* C_i = Offset_i xor ENCIPHER(K, P_i xor Offset_i) */

            ocb_block16_xor(&ctx->offset, &tmp, &tmp);

            ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);

            ocb_block16_xor(&ctx->offset, &tmp, &tmp);



            memcpy(out, tmp.c, 16);

            out += 16;

        }

    }
@@ -395,6 +394,8 @@ int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx, 
    last_len = len % 16;



    if (last_len > 0) {

        OCB_BLOCK pad;



        /* Offset_* = Offset_m xor L_* */

        ocb_block16_xor(&ctx->offset, &ctx->l_star, &ctx->offset);
@@ -402,14 +403,13 @@ int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx, 
        ctx->encrypt(ctx->offset.c, pad.c, ctx->keyenc);



        /* C_* = P_* xor Pad[1..bitlen(P_*)] */

        ocb_block_xor(in + (len / 16) * 16, (unsigned char *)&pad, last_len,

                      out + (num_blocks * 16));

        ocb_block_xor(in, pad.c, last_len, out);



        /* Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*))) */

        memset(&tmp1, 0, 16);

        memcpy(&tmp1, in + (len / 16) * 16, last_len);

        ((unsigned char *)(&tmp1))[last_len] = 0x80;

        ocb_block16_xor(&ctx->checksum, &tmp1, &ctx->checksum);

        memset(pad.c, 0, 16);           /* borrow pad */

        memcpy(pad.c, in, last_len);

        pad.c[last_len] = 0x80;

        ocb_block16_xor(&pad, &ctx->checksum, &ctx->checksum);

    }



    ctx->blocks_processed = all_num_blocks;
@@ -427,9 +427,6 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx, 
{

    u64 i, all_num_blocks;

    size_t num_blocks, last_len;

    OCB_BLOCK tmp1;

    OCB_BLOCK tmp2;

    OCB_BLOCK pad;



    /*

     * Calculate the number of blocks of data to be decrypted provided now, and
@@ -455,10 +452,10 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx, 
                    (size_t)ctx->blocks_processed + 1, ctx->offset.c,

                    (const unsigned char (*)[16])ctx->l, ctx->checksum.c);

    } else {

        OCB_BLOCK tmp;



        /* Loop through all full blocks to be decrypted */

        for (i = ctx->blocks_processed + 1; i <= all_num_blocks; i++) {

            OCB_BLOCK *inblock;

            OCB_BLOCK *outblock;



            /* Offset_i = Offset_{i-1} xor L_{ntz(i)} */

            OCB_BLOCK *lookup = ocb_lookup_l(ctx, ocb_ntz(i));
@@ -466,17 +463,19 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx, 
                return 0;

            ocb_block16_xor(&ctx->offset, lookup, &ctx->offset);



            memcpy(tmp.c, in, 16);

            in += 16;



            /* P_i = Offset_i xor DECIPHER(K, C_i xor Offset_i) */

            inblock =

                (OCB_BLOCK *)(in + ((i - ctx->blocks_processed - 1) * 16));

            ocb_block16_xor_misaligned(&ctx->offset, inblock, &tmp1);

            ctx->decrypt(tmp1.c, tmp2.c, ctx->keydec);

            outblock =

                (OCB_BLOCK *)(out + ((i - ctx->blocks_processed - 1) * 16));

            ocb_block16_xor_misaligned(&ctx->offset, &tmp2, outblock);

            ocb_block16_xor(&ctx->offset, &tmp, &tmp);

            ctx->decrypt(tmp.c, tmp.c, ctx->keydec);

            ocb_block16_xor(&ctx->offset, &tmp, &tmp);



            /* Checksum_i = Checksum_{i-1} xor P_i */

            ocb_block16_xor_misaligned(&ctx->checksum, outblock, &ctx->checksum);

            ocb_block16_xor(&tmp, &ctx->checksum, &ctx->checksum);



            memcpy(out, tmp.c, 16);

            out += 16;

        }

    }
@@ -487,6 +486,8 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx, 
    last_len = len % 16;



    if (last_len > 0) {

        OCB_BLOCK pad;



        /* Offset_* = Offset_m xor L_* */

        ocb_block16_xor(&ctx->offset, &ctx->l_star, &ctx->offset);
@@ -494,14 +495,13 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx, 
        ctx->encrypt(ctx->offset.c, pad.c, ctx->keyenc);



        /* P_* = C_* xor Pad[1..bitlen(C_*)] */

        ocb_block_xor(in + (len / 16) * 16, (unsigned char *)&pad, last_len,

                      out + (num_blocks * 16));

        ocb_block_xor(in, pad.c, last_len, out);



        /* Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*))) */

        memset(&tmp1, 0, 16);

        memcpy(&tmp1, out + (len / 16) * 16, last_len);

        ((unsigned char *)(&tmp1))[last_len] = 0x80;

        ocb_block16_xor(&ctx->checksum, &tmp1, &ctx->checksum);

        memset(pad.c, 0, 16);           /* borrow pad */

        memcpy(pad.c, out, last_len);

        pad.c[last_len] = 0x80;

        ocb_block16_xor(&pad, &ctx->checksum, &ctx->checksum);

    }



    ctx->blocks_processed = all_num_blocks;
@@ -515,15 +515,15 @@ int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx, 
int CRYPTO_ocb128_finish(OCB128_CONTEXT *ctx, const unsigned char *tag,

                         size_t len)

{

    OCB_BLOCK tmp1, tmp2;

    OCB_BLOCK tmp;



    /*

     * Tag = ENCIPHER(K, Checksum_* xor Offset_* xor L_$) xor HASH(K,A)

     */

    ocb_block16_xor(&ctx->checksum, &ctx->offset, &tmp1);

    ocb_block16_xor(&tmp1, &ctx->l_dollar, &tmp2);

    ctx->encrypt(tmp2.c, tmp1.c, ctx->keyenc);

    ocb_block16_xor(&tmp1, &ctx->sum, &ctx->tag);

    ocb_block16_xor(&ctx->checksum, &ctx->offset, &tmp);

    ocb_block16_xor(&ctx->l_dollar, &tmp, &tmp);

    ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);

    ocb_block16_xor(&tmp, &ctx->sum, &ctx->tag);



    if (len > 16 || len < 1) {

        return -1;
@@ -549,7 +549,7 @@ int CRYPTO_ocb128_tag(OCB128_CONTEXT *ctx, unsigned char *tag, size_t len) 
    CRYPTO_ocb128_finish(ctx, NULL, 0);



    /* Copy the tag into the supplied buffer */

    memcpy(tag, &ctx->tag, len);

    memcpy(tag, ctx->tag.c, len);



    return 1;

}