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From 2887a5c8f9a385b3ebee12b98f68e7d1f9cc0ea0 Mon Sep 17 00:00:00 2001
From: Eneas U de Queiroz <cote2004-github@yahoo.com>
Date: Wed, 28 Nov 2018 11:26:27 -0200
Subject: [PATCH 6/7] 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)
(cherry picked from commit b5015e834aa7d3f0a5d7585a8fae05cecbdbb848)
--- a/crypto/engine/eng_devcrypto.c
+++ b/crypto/engine/eng_devcrypto.c
@@ -47,10 +47,12 @@ static int cfd;
struct cipher_ctx {
struct session_op sess;
-
- /* to pass from init to do_cipher */
- const unsigned char *iv;
int op; /* COP_ENCRYPT or COP_DECRYPT */
+ unsigned long mode; /* EVP_CIPH_*_MODE */
+
+ /* to handle ctr mode being a stream cipher */
+ unsigned char partial[EVP_MAX_BLOCK_LENGTH];
+ unsigned int blocksize, num;
};
static const struct cipher_data_st {
@@ -87,9 +89,9 @@ static const struct cipher_data_st {
{ NID_aes_256_xts, 16, 256 / 8 * 2, 16, EVP_CIPH_XTS_MODE, CRYPTO_AES_XTS },
#endif
#if !defined(CHECK_BSD_STYLE_MACROS) || defined(CRYPTO_AES_ECB)
- { NID_aes_128_ecb, 16, 128 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
- { NID_aes_192_ecb, 16, 192 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
- { NID_aes_256_ecb, 16, 256 / 8, 16, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
+ { NID_aes_128_ecb, 16, 128 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
+ { NID_aes_192_ecb, 16, 192 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
+ { NID_aes_256_ecb, 16, 256 / 8, 0, EVP_CIPH_ECB_MODE, CRYPTO_AES_ECB },
#endif
#if 0 /* Not yet supported */
{ NID_aes_128_gcm, 16, 128 / 8, 16, EVP_CIPH_GCM_MODE, CRYPTO_AES_GCM },
@@ -146,6 +148,8 @@ static int cipher_init(EVP_CIPHER_CTX *c
cipher_ctx->sess.keylen = cipher_d->keylen;
cipher_ctx->sess.key = (void *)key;
cipher_ctx->op = enc ? COP_ENCRYPT : COP_DECRYPT;
+ cipher_ctx->mode = cipher_d->flags & EVP_CIPH_MODE;
+ cipher_ctx->blocksize = cipher_d->blocksize;
if (ioctl(cfd, CIOCGSESSION, &cipher_ctx->sess) < 0) {
SYSerr(SYS_F_IOCTL, errno);
return 0;
@@ -160,8 +164,11 @@ static int cipher_do_cipher(EVP_CIPHER_C
struct cipher_ctx *cipher_ctx =
(struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
struct crypt_op cryp;
+ unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
#if !defined(COP_FLAG_WRITE_IV)
unsigned char saved_iv[EVP_MAX_IV_LENGTH];
+ const unsigned char *ivptr;
+ size_t nblocks, ivlen;
#endif
memset(&cryp, 0, sizeof(cryp));
@@ -169,19 +176,28 @@ static int cipher_do_cipher(EVP_CIPHER_C
cryp.len = inl;
cryp.src = (void *)in;
cryp.dst = (void *)out;
- cryp.iv = (void *)EVP_CIPHER_CTX_iv_noconst(ctx);
+ cryp.iv = (void *)iv;
cryp.op = cipher_ctx->op;
#if !defined(COP_FLAG_WRITE_IV)
cryp.flags = 0;
- if (EVP_CIPHER_CTX_iv_length(ctx) > 0) {
- assert(inl >= EVP_CIPHER_CTX_iv_length(ctx));
- if (!EVP_CIPHER_CTX_encrypting(ctx)) {
- unsigned char *ivptr = in + inl - EVP_CIPHER_CTX_iv_length(ctx);
+ ivlen = EVP_CIPHER_CTX_iv_length(ctx);
+ if (ivlen > 0)
+ switch (cipher_ctx->mode) {
+ case EVP_CIPH_CBC_MODE:
+ assert(inl >= ivlen);
+ if (!EVP_CIPHER_CTX_encrypting(ctx)) {
+ ivptr = in + inl - ivlen;
+ memcpy(saved_iv, ivptr, ivlen);
+ }
+ break;
+
+ case EVP_CIPH_CTR_MODE:
+ break;
- memcpy(saved_iv, ivptr, EVP_CIPHER_CTX_iv_length(ctx));
+ default: /* should not happen */
+ return 0;
}
- }
#else
cryp.flags = COP_FLAG_WRITE_IV;
#endif
@@ -192,17 +208,74 @@ static int cipher_do_cipher(EVP_CIPHER_C
}
#if !defined(COP_FLAG_WRITE_IV)
- if (EVP_CIPHER_CTX_iv_length(ctx) > 0) {
- unsigned char *ivptr = saved_iv;
+ if (ivlen > 0)
+ switch (cipher_ctx->mode) {
+ case EVP_CIPH_CBC_MODE:
+ assert(inl >= ivlen);
+ if (EVP_CIPHER_CTX_encrypting(ctx))
+ ivptr = out + inl - ivlen;
+ else
+ ivptr = saved_iv;
+
+ memcpy(iv, ivptr, ivlen);
+ break;
+
+ case EVP_CIPH_CTR_MODE:
+ nblocks = (inl + cipher_ctx->blocksize - 1)
+ / cipher_ctx->blocksize;
+ do {
+ ivlen--;
+ nblocks += iv[ivlen];
+ iv[ivlen] = (uint8_t) nblocks;
+ nblocks >>= 8;
+ } while (ivlen);
+ break;
+
+ default: /* should not happen */
+ return 0;
+ }
+#endif
+
+ return 1;
+}
- assert(inl >= EVP_CIPHER_CTX_iv_length(ctx));
- if (!EVP_CIPHER_CTX_encrypting(ctx))
- ivptr = out + inl - EVP_CIPHER_CTX_iv_length(ctx);
+static int ctr_do_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
+ const unsigned char *in, size_t inl)
+{
+ struct cipher_ctx *cipher_ctx =
+ (struct cipher_ctx *)EVP_CIPHER_CTX_get_cipher_data(ctx);
+ size_t nblocks, len;
- memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), ivptr,
- EVP_CIPHER_CTX_iv_length(ctx));
+ /* initial partial block */
+ while (cipher_ctx->num && inl) {
+ (*out++) = *(in++) ^ cipher_ctx->partial[cipher_ctx->num];
+ --inl;
+ cipher_ctx->num = (cipher_ctx->num + 1) % cipher_ctx->blocksize;
+ }
+
+ /* full blocks */
+ if (inl > (unsigned int) cipher_ctx->blocksize) {
+ nblocks = inl/cipher_ctx->blocksize;
+ len = nblocks * cipher_ctx->blocksize;
+ if (cipher_do_cipher(ctx, out, in, len) < 1)
+ return 0;
+ inl -= len;
+ out += len;
+ in += len;
+ }
+
+ /* final partial block */
+ if (inl) {
+ memset(cipher_ctx->partial, 0, cipher_ctx->blocksize);
+ if (cipher_do_cipher(ctx, cipher_ctx->partial, cipher_ctx->partial,
+ cipher_ctx->blocksize) < 1)
+ return 0;
+ while (inl--) {
+ out[cipher_ctx->num] = in[cipher_ctx->num]
+ ^ cipher_ctx->partial[cipher_ctx->num];
+ cipher_ctx->num++;
+ }
}
-#endif
return 1;
}
@@ -249,6 +322,7 @@ static void prepare_cipher_methods(void)
{
size_t i;
struct session_op sess;
+ unsigned long cipher_mode;
memset(&sess, 0, sizeof(sess));
sess.key = (void *)"01234567890123456789012345678901234567890123456789";
@@ -266,9 +340,12 @@ static void prepare_cipher_methods(void)
|| ioctl(cfd, CIOCFSESSION, &sess.ses) < 0)
continue;
+ cipher_mode = cipher_data[i].flags & EVP_CIPH_MODE;
+
if ((known_cipher_methods[i] =
EVP_CIPHER_meth_new(cipher_data[i].nid,
- cipher_data[i].blocksize,
+ cipher_mode == EVP_CIPH_CTR_MODE ? 1 :
+ cipher_data[i].blocksize,
cipher_data[i].keylen)) == NULL
|| !EVP_CIPHER_meth_set_iv_length(known_cipher_methods[i],
cipher_data[i].ivlen)
@@ -278,6 +355,8 @@ static void prepare_cipher_methods(void)
| EVP_CIPH_FLAG_DEFAULT_ASN1)
|| !EVP_CIPHER_meth_set_init(known_cipher_methods[i], cipher_init)
|| !EVP_CIPHER_meth_set_do_cipher(known_cipher_methods[i],
+ cipher_mode == EVP_CIPH_CTR_MODE ?
+ ctr_do_cipher :
cipher_do_cipher)
|| !EVP_CIPHER_meth_set_ctrl(known_cipher_methods[i], cipher_ctrl)
|| !EVP_CIPHER_meth_set_cleanup(known_cipher_methods[i],
|
