[PATCH 3.4 03/25] crypto: authenc - Find proper IV address in ablkcipher callback

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tom Lendacky <thomas.lendacky@amd.com>

commit fc019c7122dfcd69c50142b57a735539aec5da95 upstream.

When performing an asynchronous ablkcipher operation the authenc
completion callback routine is invoked, but it does not locate and use
the proper IV.

The callback routine, crypto_authenc_encrypt_done, is updated to use
the same method of calculating the address of the IV as is done in
crypto_authenc_encrypt function which sets up the callback.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 crypto/authenc.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -368,9 +368,10 @@ static void crypto_authenc_encrypt_done(
 	if (!err) {
 		struct crypto_aead *authenc = crypto_aead_reqtfm(areq);
 		struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
-		struct ablkcipher_request *abreq = aead_request_ctx(areq);
-		u8 *iv = (u8 *)(abreq + 1) +
-			 crypto_ablkcipher_reqsize(ctx->enc);
+		struct authenc_request_ctx *areq_ctx = aead_request_ctx(areq);
+		struct ablkcipher_request *abreq = (void *)(areq_ctx->tail
+							    + ctx->reqoff);
+		u8 *iv = (u8 *)abreq - crypto_ablkcipher_ivsize(ctx->enc);
 
 		err = crypto_authenc_genicv(areq, iv, 0);
 	}