From: Michael Brown <mcb30@ipxe.org>
Date: Thu, 27 Sep 2012 00:37:06 +0000 (+0100)
Subject: [crypto] Allow in-place CBC decryption
X-Git-Tag: v1.20.1~1639
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=09d45ffd7991e6b64a76d86f338a2f0973527be6;p=thirdparty%2Fipxe.git

[crypto] Allow in-place CBC decryption

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/crypto/cbc.c b/src/crypto/cbc.c
index 28d38b2db..9bf0e8b49 100644
--- a/src/crypto/cbc.c
+++ b/src/crypto/cbc.c
@@ -88,13 +88,15 @@ void cbc_encrypt ( void *ctx, const void *src, void *dst, size_t len,
 void cbc_decrypt ( void *ctx, const void *src, void *dst, size_t len,
 		   struct cipher_algorithm *raw_cipher, void *cbc_ctx ) {
 	size_t blocksize = raw_cipher->blocksize;
+	uint8_t next_cbc_ctx[blocksize];
 
 	assert ( ( len % blocksize ) == 0 );
 
 	while ( len ) {
+		memcpy ( next_cbc_ctx, src, blocksize );
 		cipher_decrypt ( raw_cipher, ctx, src, dst, blocksize );
 		cbc_xor ( cbc_ctx, dst, blocksize );
-		memcpy ( cbc_ctx, src, blocksize );
+		memcpy ( cbc_ctx, next_cbc_ctx, blocksize );
 		dst += blocksize;
 		src += blocksize;
 		len -= blocksize;