git: d55df8dcf7ec - main - crypto: Move CBC handling into enc_xform_aes_cbc.

The branch main has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=d55df8dcf7ecb7f12bb113b3cdcf91c7d5640352

commit d55df8dcf7ecb7f12bb113b3cdcf91c7d5640352
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2021-12-16 21:47:44 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2021-12-16 21:47:44 +0000

    crypto: Move CBC handling into enc_xform_aes_cbc.
    
    Add an IV to the context that is initialized by the reinit hook.
    Encrypt and decrypt operations handle cipher block chaining along with
    updating the IV saved in the context.
    
    Reviewed by:    markj
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D33487
---
 sys/opencrypto/xform_aes_cbc.c | 44 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 37 insertions(+), 7 deletions(-)

diff --git a/sys/opencrypto/xform_aes_cbc.c b/sys/opencrypto/xform_aes_cbc.c
index 38b7aeb33ec2..b2a45e595fda 100644
--- a/sys/opencrypto/xform_aes_cbc.c
+++ b/sys/opencrypto/xform_aes_cbc.c
@@ -53,15 +53,21 @@ __FBSDID("$FreeBSD$");
 #include <crypto/rijndael/rijndael.h>
 #include <opencrypto/xform_enc.h>
 
+struct aes_cbc_ctx {
+	rijndael_ctx key;
+	char iv[AES_BLOCK_LEN];
+};
+
 static	int aes_cbc_setkey(void *, const uint8_t *, int);
 static	void aes_cbc_encrypt(void *, const uint8_t *, uint8_t *);
 static	void aes_cbc_decrypt(void *, const uint8_t *, uint8_t *);
+static  void aes_cbc_reinit(void *, const uint8_t *, size_t);
 
 /* Encryption instances */
 const struct enc_xform enc_xform_aes_cbc = {
 	.type = CRYPTO_AES_CBC,
 	.name = "AES-CBC",
-	.ctxsize = sizeof(rijndael_ctx),
+	.ctxsize = sizeof(struct aes_cbc_ctx),
 	.blocksize = AES_BLOCK_LEN,
 	.ivsize = AES_BLOCK_LEN,
 	.minkey = AES_MIN_KEY,
@@ -69,30 +75,54 @@ const struct enc_xform enc_xform_aes_cbc = {
 	.encrypt = aes_cbc_encrypt,
 	.decrypt = aes_cbc_decrypt,
 	.setkey = aes_cbc_setkey,
+	.reinit = aes_cbc_reinit,
 };
 
 /*
  * Encryption wrapper routines.
  */
 static void
-aes_cbc_encrypt(void *key, const uint8_t *in, uint8_t *out)
+aes_cbc_encrypt(void *vctx, const uint8_t *in, uint8_t *out)
 {
-	rijndael_encrypt(key, in, out);
+	struct aes_cbc_ctx *ctx = vctx;
+
+	for (u_int i = 0; i < AES_BLOCK_LEN; i++)
+		out[i] = in[i] ^ ctx->iv[i];
+	rijndael_encrypt(&ctx->key, out, out);
+	memcpy(ctx->iv, out, AES_BLOCK_LEN);
 }
 
 static void
-aes_cbc_decrypt(void *key, const uint8_t *in, uint8_t *out)
+aes_cbc_decrypt(void *vctx, const uint8_t *in, uint8_t *out)
 {
-	rijndael_decrypt(key, in, out);
+	struct aes_cbc_ctx *ctx = vctx;
+	char block[AES_BLOCK_LEN];
+
+	memcpy(block, in, AES_BLOCK_LEN);
+	rijndael_decrypt(&ctx->key, in, out);
+	for (u_int i = 0; i < AES_BLOCK_LEN; i++)
+		out[i] ^= ctx->iv[i];
+	memcpy(ctx->iv, block, AES_BLOCK_LEN);
+	explicit_bzero(block, sizeof(block));
 }
 
 static int
-aes_cbc_setkey(void *sched, const uint8_t *key, int len)
+aes_cbc_setkey(void *vctx, const uint8_t *key, int len)
 {
+	struct aes_cbc_ctx *ctx = vctx;
 
 	if (len != 16 && len != 24 && len != 32)
 		return (EINVAL);
 
-	rijndael_set_key(sched, key, len * 8);
+	rijndael_set_key(&ctx->key, key, len * 8);
 	return (0);
 }
+
+static void
+aes_cbc_reinit(void *vctx, const uint8_t *iv, size_t iv_len)
+{
+	struct aes_cbc_ctx *ctx = vctx;
+
+	KASSERT(iv_len == sizeof(ctx->iv), ("%s: bad IV length", __func__));
+	memcpy(ctx->iv, iv, sizeof(ctx->iv));
+}