[openssl-dev] Possible bug in crypto/evp/e_aes.c:aes_cbc_cipher

[Andy Polyakov]

Hi,

> I'was tracking a segfault in EVP_OpneUdate and stumbled on following:
> 
> static int aes_cbc_cipher(EVP_CIPHER_CTX *ctx,unsigned char *out,
> 	const unsigned char *in, size_t len)
> {
> 	EVP_AES_KEY *dat = (EVP_AES_KEY *)ctx->cipher_data;
> 
> 	if (dat->stream.cbc)
> 		(*dat->stream.cbc)(in,out,len,&dat->ks,ctx->iv,ctx->encrypt);
> 	else if (ctx->encrypt)
> 	 CRYPTO_cbc128_encrypt(in,out,len,&dat->ks,ctx->iv,dat->block);
> 	else
> 	 CRYPTO_cbc128_encrypt(in,out,len,&dat->ks,ctx->iv,dat->block); 
> 
> 	return 1;
> }
> 
> 
> I think that the second call to CRYPTO_cbc128_encrypt  should be actually to
> CRYPTO_cbc128_decrypt.

Yes, it's a typo, and it was fixed in development branches. One
naturally wonders how did it work? The truth is that that call is never
made, because dat->stream.cbc is always initialized. At least was so far.