From: Andre Noll <maan@tuebingen.mpg.de>
Date: Sun, 28 Aug 2016 13:35:53 +0000 (+0200)
Subject: openssl: Use EVP API for AES.
X-Git-Tag: v0.5.7~12^2~1
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=698178774b857a8959fe70e360ae6ff755eacf8e

openssl: Use EVP API for AES.

opensssl-1.1 no longer exports AES_set_encrypt_key() and
AES_ctr128_encrypt(). Applications are supposed to use the high-level
EVP interface instead.

Fortunately, the EVP library functions necessary for our use of
the AES_ctr128 stream cipher are available in openssl version 1.0.1
and above, so switching to the EVP API makes the code work with all
versions >= 1.0.1.
---

diff --git a/crypt.c b/crypt.c
index 610d2057..06ae6265 100644
--- a/crypt.c
+++ b/crypt.c
@@ -260,27 +260,18 @@ int pub_encrypt(struct asymmetric_key *pub, unsigned char *inbuf,
 	return ret < 0? -E_ENCRYPT : ret;
 }
 
-struct aes_ctr_128_context {
-	AES_KEY key;
-	unsigned char ivec[AES_CRT128_BLOCK_SIZE];
-	unsigned char ecount[AES_CRT128_BLOCK_SIZE];
-	unsigned int num;
-};
-
 struct stream_cipher {
 	bool use_aes;
 	union {
 		RC4_KEY rc4_key;
-		struct aes_ctr_128_context aes;
+		EVP_CIPHER_CTX *aes;
 	} context;
 };
 
 struct stream_cipher *sc_new(const unsigned char *data, int len,
 		bool use_aes)
 {
-	int ret;
 	struct stream_cipher *sc = para_malloc(sizeof(*sc));
-	struct aes_ctr_128_context *aes;
 
 	sc->use_aes = use_aes;
 	if (!use_aes) {
@@ -288,17 +279,17 @@ struct stream_cipher *sc_new(const unsigned char *data, int len,
 		return sc;
 	}
 	assert(len >= 2 * AES_CRT128_BLOCK_SIZE);
-	aes = &sc->context.aes;
-	ret = AES_set_encrypt_key(data, AES_CRT128_BLOCK_SIZE * 8 /* bits */,
-		&aes->key);
-	assert(ret == 0);
-	memcpy(aes->ivec, data + AES_CRT128_BLOCK_SIZE, AES_CRT128_BLOCK_SIZE);
-	aes->num = 0;
+	sc->context.aes = EVP_CIPHER_CTX_new();
+	EVP_EncryptInit_ex(sc->context.aes, EVP_aes_128_ctr(), NULL, data,
+		data + AES_CRT128_BLOCK_SIZE);
 	return sc;
 }
 
 void sc_free(struct stream_cipher *sc)
 {
+	if (!sc)
+		return;
+	EVP_CIPHER_CTX_free(sc->context.aes);
 	free(sc);
 }
 
@@ -332,25 +323,29 @@ static void rc4_crypt(RC4_KEY *key, struct iovec *src, struct iovec *dst)
 	((char *)dst->iov_base)[len] = '\0';
 }
 
-static void aes_ctr128_crypt(struct aes_ctr_128_context *aes, struct iovec *src,
+static void aes_ctr128_crypt(EVP_CIPHER_CTX *ctx, struct iovec *src,
 		struct iovec *dst)
 {
-	size_t len = src->iov_len;
+	int ret, inlen = src->iov_len, outlen, tmplen;
 
 	*dst = (typeof(*dst)) {
 		/* Add one for the terminating zero byte. */
-		.iov_base = para_malloc(len + 1),
-		.iov_len = len
+		.iov_base = para_malloc(inlen + 1),
+		.iov_len = inlen
 	};
-	AES_ctr128_encrypt(src->iov_base, dst->iov_base, len,
-		&aes->key, aes->ivec, aes->ecount, &aes->num);
-	((char *)dst->iov_base)[len] = '\0';
+	ret = EVP_EncryptUpdate(ctx, dst->iov_base, &outlen, src->iov_base, inlen);
+	assert(ret != 0);
+	ret = EVP_EncryptFinal_ex(ctx, dst->iov_base + outlen, &tmplen);
+	assert(ret != 0);
+	outlen += tmplen;
+	((char *)dst->iov_base)[outlen] = '\0';
+	dst->iov_len = outlen;
 }
 
 void sc_crypt(struct stream_cipher *sc, struct iovec *src, struct iovec *dst)
 {
 	if (sc->use_aes)
-		return aes_ctr128_crypt(&sc->context.aes, src, dst);
+		return aes_ctr128_crypt(sc->context.aes, src, dst);
 	return rc4_crypt(&sc->context.rc4_key, src, dst);
 }