From fa5846e58b2caecbb33460a7d6f78b02719d312e Mon Sep 17 00:00:00 2001 From: Richard Levitte Date: Wed, 15 Oct 2003 09:00:18 +0000 Subject: [PATCH] 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 . The unnecessary memcpy() was found as an effect of investigating that error. --- crypto/aes/aes_cbc.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) 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); } } } -- 2.25.1