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eng_devcrypto: fix ctr mode
Make CTR mode behave like a stream cipher. Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com> Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/7585)
This commit is contained in:
Eneas U de Queiroz
Richard Levitte
parent
6d99e23839
commit
b5015e834a
@ -47,10 +47,12 @@ static int cfd;
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struct cipher_ctx {
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struct session_op sess;
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/* to pass from init to do_cipher */
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const unsigned char *iv;
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int op; /* COP_ENCRYPT or COP_DECRYPT */
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unsigned long mode; /* EVP_CIPH_*_MODE */
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/* to handle ctr mode being a stream cipher */
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unsigned char partial[EVP_MAX_BLOCK_LENGTH];
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unsigned int blocksize, num;
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};
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static const struct cipher_data_st {
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@ -87,9 +89,9 @@ static const struct cipher_data_st {
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{ NID_aes_256_xts, 16, 256 / 8 * 2, 16, EVP_CIPH_XTS_MODE, CRYPTO_AES_XTS },
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#endif
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#if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_AES_ECB)
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{ NID_aes_128_ecb, 16, 128 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
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{ NID_aes_192_ecb, 16, 192 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
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{ NID_aes_256_ecb, 16, 256 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
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{ NID_aes_128_ecb, 16, 128 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
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{ NID_aes_192_ecb, 16, 192 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
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{ NID_aes_256_ecb, 16, 256 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
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#endif
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#if 0 /* Not yet supported */
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{ NID_aes_128_gcm, 16, 128 / 8, 16, EVP_CIPH_GCM_MODE, CRYPTO_AES_GCM },
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@ -146,6 +148,8 @@ static int cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
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cipher_ctx->sess.keylen = cipher_d->keylen;
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cipher_ctx->sess.key = (void *)key;
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cipher_ctx->op = enc ? COP_ENCRYPT : COP_DECRYPT;
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cipher_ctx->mode = cipher_d->flags & EVP_CIPH_MODE;
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cipher_ctx->blocksize = cipher_d->blocksize;
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if (ioctl(cfd, CIOCGSESSION, &cipher_ctx->sess) < 0) {
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SYSerr(SYS_F_IOCTL, errno);
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return 0;
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@ -160,8 +164,11 @@ static int cipher_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
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struct cipher_ctx *cipher_ctx =
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(struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
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struct crypt_op cryp;
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unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
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#if !defined(COP_FLAG_WRITE_IV)
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unsigned char saved_iv[EVP_MAX_IV_LENGTH];
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const unsigned char *ivptr;
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size_t nblocks, ivlen;
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#endif
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memset(&cryp, 0, sizeof(cryp));
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@ -169,19 +176,28 @@ static int cipher_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
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cryp.len = inl;
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cryp.src = (void *)in;
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cryp.dst = (void *)out;
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cryp.iv = (void *)EVP_CIPHER_CTX_iv_noconst(ctx);
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cryp.iv = (void *)iv;
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cryp.op = cipher_ctx->op;
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#if !defined(COP_FLAG_WRITE_IV)
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cryp.flags = 0;
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if (EVP_CIPHER_CTX_iv_length(ctx) > 0) {
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assert(inl >= EVP_CIPHER_CTX_iv_length(ctx));
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if (!EVP_CIPHER_CTX_encrypting(ctx)) {
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unsigned char *ivptr = in + inl - EVP_CIPHER_CTX_iv_length(ctx);
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ivlen = EVP_CIPHER_CTX_iv_length(ctx);
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if (ivlen > 0)
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switch (cipher_ctx->mode) {
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case EVP_CIPH_CBC_MODE:
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assert(inl >= ivlen);
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if (!EVP_CIPHER_CTX_encrypting(ctx)) {
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ivptr = in + inl - ivlen;
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memcpy(saved_iv, ivptr, ivlen);
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}
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break;
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memcpy(saved_iv, ivptr, EVP_CIPHER_CTX_iv_length(ctx));
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case EVP_CIPH_CTR_MODE:
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break;
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default: /* should not happen */
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return 0;
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}
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}
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#else
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cryp.flags = COP_FLAG_WRITE_IV;
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#endif
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@ -192,21 +208,78 @@ static int cipher_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
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}
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#if !defined(COP_FLAG_WRITE_IV)
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if (EVP_CIPHER_CTX_iv_length(ctx) > 0) {
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unsigned char *ivptr = saved_iv;
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if (ivlen > 0)
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switch (cipher_ctx->mode) {
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case EVP_CIPH_CBC_MODE:
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assert(inl >= ivlen);
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if (EVP_CIPHER_CTX_encrypting(ctx))
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ivptr = out + inl - ivlen;
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else
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ivptr = saved_iv;
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assert(inl >= EVP_CIPHER_CTX_iv_length(ctx));
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if (!EVP_CIPHER_CTX_encrypting(ctx))
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ivptr = out + inl - EVP_CIPHER_CTX_iv_length(ctx);
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memcpy(iv, ivptr, ivlen);
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break;
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memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), ivptr,
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EVP_CIPHER_CTX_iv_length(ctx));
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}
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case EVP_CIPH_CTR_MODE:
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nblocks = (inl + cipher_ctx->blocksize - 1)
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/ cipher_ctx->blocksize;
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do {
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ivlen--;
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nblocks += iv[ivlen];
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iv[ivlen] = (uint8_t) nblocks;
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nblocks >>= 8;
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} while (ivlen);
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break;
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default: /* should not happen */
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return 0;
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}
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#endif
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return 1;
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}
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static int ctr_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
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const unsigned char *in, size_t inl)
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{
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struct cipher_ctx *cipher_ctx =
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(struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
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size_t nblocks, len;
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/* initial partial block */
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while (cipher_ctx->num && inl) {
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(*out++) = *(in++) ^ cipher_ctx->partial[cipher_ctx->num];
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--inl;
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cipher_ctx->num = (cipher_ctx->num + 1) % cipher_ctx->blocksize;
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}
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/* full blocks */
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if (inl > (unsigned int) cipher_ctx->blocksize) {
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nblocks = inl/cipher_ctx->blocksize;
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len = nblocks * cipher_ctx->blocksize;
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if (cipher_do_cipher(ctx, out, in, len) < 1)
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return 0;
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inl -= len;
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out += len;
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in += len;
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}
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/* final partial block */
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if (inl) {
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memset(cipher_ctx->partial, 0, cipher_ctx->blocksize);
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if (cipher_do_cipher(ctx, cipher_ctx->partial, cipher_ctx->partial,
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cipher_ctx->blocksize) < 1)
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return 0;
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while (inl--) {
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out[cipher_ctx->num] = in[cipher_ctx->num]
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^ cipher_ctx->partial[cipher_ctx->num];
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cipher_ctx->num++;
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}
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}
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return 1;
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}
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static int cipher_ctrl(EVP_CIPHER_CTX *ctx, int type, int p1, void* p2)
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{
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EVP_CIPHER_CTX *to_ctx = (EVP_CIPHER_CTX *)p2;
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@ -249,6 +322,7 @@ static void prepare_cipher_methods(void)
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{
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size_t i;
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struct session_op sess;
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unsigned long cipher_mode;
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memset(&sess, 0, sizeof(sess));
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sess.key = (void *)"01234567890123456789012345678901234567890123456789";
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@ -266,9 +340,12 @@ static void prepare_cipher_methods(void)
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|| ioctl(cfd, CIOCFSESSION, &sess.ses) < 0)
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continue;
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cipher_mode = cipher_data[i].flags & EVP_CIPH_MODE;
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if ((known_cipher_methods[i] =
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EVP_CIPHER_meth_new(cipher_data[i].nid,
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cipher_data[i].blocksize,
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cipher_mode == EVP_CIPH_CTR_MODE ? 1 :
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cipher_data[i].blocksize,
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cipher_data[i].keylen)) == NULL
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|| !EVP_CIPHER_meth_set_iv_length(known_cipher_methods[i],
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cipher_data[i].ivlen)
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@ -278,6 +355,8 @@ static void prepare_cipher_methods(void)
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| EVP_CIPH_FLAG_DEFAULT_ASN1)
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|| !EVP_CIPHER_meth_set_init(known_cipher_methods[i], cipher_init)
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|| !EVP_CIPHER_meth_set_do_cipher(known_cipher_methods[i],
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cipher_mode == EVP_CIPH_CTR_MODE ?
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ctr_do_cipher :
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cipher_do_cipher)
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|| !EVP_CIPHER_meth_set_ctrl(known_cipher_methods[i], cipher_ctrl)
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|| !EVP_CIPHER_meth_set_cleanup(known_cipher_methods[i],
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