From: Richard Levitte <levitte@openssl.org>
Date: Wed, 15 Oct 2003 09:00:18 +0000 (+0000)
Subject: Correct serious bug in AES-CBC decryption when the message length isn't
X-Git-Tag: OpenSSL_0_9_7d~87
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=fa5846e58b2caecbb33460a7d6f78b02719d312e;p=oweals%2Fopenssl.git

Correct serious bug in AES-CBC decryption when the message length isn't
a multiple of AES_BLOCK_SIZE.
Optimize decryption of all complete blocks in AES-CBC by removing an
unnecessary memcpy().

The error was notified by James Fernandes <jf210032@exchange.DAYTONOH.NCR.com>.
The unnecessary memcpy() was found as an effect of investigating that error.
---

diff --git a/crypto/aes/aes_cbc.c b/crypto/aes/aes_cbc.c
index 86b27b10d6..0a28ab8d34 100644
--- a/crypto/aes/aes_cbc.c
+++ b/crypto/aes/aes_cbc.c
@@ -91,21 +91,20 @@ void AES_cbc_encrypt(const unsigned char *in, unsigned char *out,
 		}			
 	} else {
 		while (len >= AES_BLOCK_SIZE) {
-			memcpy(tmp, in, AES_BLOCK_SIZE);
 			AES_decrypt(in, out, key);
 			for(n=0; n < AES_BLOCK_SIZE; ++n)
 				out[n] ^= ivec[n];
-			memcpy(ivec, tmp, AES_BLOCK_SIZE);
+			memcpy(ivec, in, AES_BLOCK_SIZE);
 			len -= AES_BLOCK_SIZE;
 			in += AES_BLOCK_SIZE;
 			out += AES_BLOCK_SIZE;
 		}
 		if (len) {
 			memcpy(tmp, in, AES_BLOCK_SIZE);
-			AES_decrypt(tmp, tmp, key);
+			AES_decrypt(in, tmp, key);
 			for(n=0; n < len; ++n)
-				out[n] ^= ivec[n];
-			memcpy(ivec, tmp, AES_BLOCK_SIZE);
+				out[n] = tmp[n] ^ ivec[n];
+			memcpy(ivec, in, AES_BLOCK_SIZE);
 		}			
 	}
 }